STONE AGE TECHNOLOGY AND ESTIMATING THE AGE OF SUCH ITEMS
I joined the US Navy in 1944 and was sent to
Boot Camp at Great Lakes, IL, just North of Chicago.
This was the first time I had been outside the state of Florida
since moving there from Louisiana at age 2 years. Some of my shipmates
from New York and other big Northern cities soon picked up on my rustic
ways and I was asked more than once what people did for amusement in those
small jerkwater towns where, as rumor had it, many of them rolled up the
sidewalks after dark. This
attitude was a bit puzzling to me because I couldn’t recall ever being
bored for a lack of something interesting to do.
Boot Camp was, as intended, very stressful with many demands being
imposed on the body and spirit at all times and when the occasion did
arise when I could fantasize about being allowed a few days off when Boot
Camp was over, visiting my favorite arrowhead hunting grounds was a high
Gainesville, Florida, my hometown, could never be
mistaken for a jerkwater, but it was usually a pretty sleepy place.
The main industry was the University of Florida, but there was also
a creosote plant and a mattress factory and a couple of lumber mills.
Beer was available on tap and in bottles, but the county was dry so
far as legal whiskey and wine was concerned.
Illegal supplies of these beverages were readily available,
however, at premium prices and from a number of suppliers.
The main entertainment centers in 1944 were 3 air conditioned
indoor movie theaters downtown and 2 drive-in theaters on the outskirts of
town. A couple of “Night Clubs” with live dance music, beer and dining were
also in business outside the city limits.
These were required to close shop around midnight, perhaps as late
as 1AM. They were decidedly
very far above and beyond my limited budget.
around with my buddies, Snubby Bailey and Billy Hartman mainly, hunting
for arrowheads and camping out with them was my first choice for
entertainment when I had a few hours or more to spend in idle pursuits.
I also managed to see a movie on many Saturday nights.
There were times when we would leave our jobs at 6PM on Saturday,
ride our bicycles to one or another prime hunting ground, and set up a
camp nearby with a tarp, bedrolls, firewood, beans and coffee.
We could hunt for arrowheads until dusk, around 8:30PM, and then
ride back to town to catch the last picture show after 9:30PM.
The newsreel, cartoon, and short features, plus the main event
would usually last until around midnight.
But we were young and foolish in those days, so when we returned to
our camp we would build a fire and put on a pot of coffee and shoot the
bull until perhaps 2:30AM. There was no alarm clock in the morning, except a distended
bladder, and the sun was usually high in the sky when we finally got up
and made breakfast. A can of
beans and the leftover coffee was more than adequate.
Snubby usually had major chores to do at home, like mowing the
lawn, and he went to the evening church services as well, but there was
plenty of time to walk up and down the furrows if we were camped near a
farmer’s field or to make a serious pass over the open ground wherever
we happened to be.
parents were quite accustomed to my random comings and goings and we could
usually transact whatever business we had between the time I came home
late Sunday afternoon and bedtime. On many occasions I would have time to wander into the
backwoods near my home before sundown.
The scene did not change very much over time, but I always found it
interesting… the water level in the swamps and the canal… the birds
and snakes and other creatures.
I was always on the alert for snakes and arrowheads back there, but
unless the earth was free of vegetation there was little chance of finding
artifacts of any kind. There
was a network of fire-gaps, deep furrows perhaps 8 feet wide made by a
tractor, throughout the forest and I have several choice specimens found
while wandering along these trails. In
time my buddies and I came to believe that almost any bare patch of earth
as large as 5 acres or more anywhere in Florida would yield at least some
evidence of Pre-Columbian human habitation to our sharp eyes.
(See row 2 items 5, 6, 7, 8, &9.
Item 13 row 2 was found by my mother in her garden… the only one
found there… after she had farmed there for 20 + years).
interest in arrowheads began when I was around 5 years old in 1931 - 32.
My folks had recently moved to the place that was to be my home
until I joined the Navy in 1944. This place was roughly midway between
Gainesville and Fairbanks, some 6 miles down the road toward Waldo.
It could fairly be said that we lived “out in the sticks”.
Our nearest neighbors lived ¼ mile away across the Waldo Road and
the railroad tracks. On our
side of the road our nearest neighbors were roughly a mile away.
The terrain on our side of the road was a mostly pine forest and
palmetto thicket with half-a-dozen cypress swamps, each covering perhaps
an acre or two up to some 20 - 30 acres.
The Little Hatchet Creek drained the forest and the largest swamps
into Newnan’s Lake, some 3 miles to the East.
A network of canals had been dug to facilitate the drainage of the
smaller swamps into the creek.
The purpose was to minimize the amount of standing water in the
swamps and thus the breeding grounds for mosquitoes.
However, judging from the size of the swarms of mosquitoes that
were always present, I would guess that the effort was wholly ineffective.
But, of course, I had no way to compare what the situation might
have been without these measures.
In any event the pinewoods and palmetto thickets
near home and the canal through my mother’s garden were exciting places
to explore. One day while
walking along the top of the ridge beside this canal I saw a large white
object about 5 inches long, pointed and very symmetrical, on top of a dirt
pedestal about 2 inches above the surrounding earth.
The heavy rains on the sandy soil tend to produce such formations
around any hard object. I had
no idea what it was, but I was very excited to find it.
I picked it up and ran for home as fast as I could manage. My father told me that it was an Indian Arrowhead and that
the Indians, who had once lived hereabouts, made them of stone and used
them for hunting game. He
went on to explain that the Indians were very wise in the ways of the
forest. They knew all of the
habits of the wild animals there and made their living by hunting and
fishing with only the most primitive tools and methods.
I was very excited by his description of the Indian way of life and
I thought that I could want for nothing more than to live as they did in
the backwoods and to learn all about the fish and the habits of the wild
no longer have that first arrowhead, but for an idea of what it was like,
look at No. 7 from the left in the 2nd row from the top in the
picture, Figure 1.)
In time I gained total access to the backwoods and
the creeks and I was always on the sharp lookout for another arrowhead,
but it was perhaps 2 years before I found another one.
I had better luck finding petrified shark’s teeth in the Little
Hatchet Creek, as I have described elsewhere.
the meanwhile my father found work as a surveyor on the Florida Barge
Canal project. There he found
a dozen or so arrowheads as well as a number of beautiful limestone
fossils. I shared these
treasures with Mrs. Carl Stengle. Her
husband was a larger-than-life gentleman who owned the flying school and a
grass landing strip for light aircraft across the Waldo Road from my home.
When I wasn’t fishing in the creeks or the deeper holes in the
canal or potting about in the woods, I was generally hanging around with
Carl and/or his employees and the student fliers.
when I was roughly 8 - 9 years old Mrs. Stengle took me to the University
of Florida museum with my shoebox full of arrowheads and fossils… all in
packing material to keep them from rubbing against each other.
She was very encouraging with regard to my interest in science and
hoped that the people at the museum would inspire me further.
I learned, instead, that arrowheads were “as common as dirt”
and all but worthless to archaeologists.
Likewise the shark teeth and the fossils.
One of the archaeologists mentioned in passing that things might be
different if, somehow, it was possible to tell how old the arrowheads
were. But, alas, there was
simply no way.
old man, one Richard O’Malley, a friend of my family, had told me that
the shark teeth were known to be roughly 25 million years old.
Geologists knew this, he told me, from studies of the layers of
sediment. The rivers and streams washed mud and silt down to the ocean
every year, he said, and it settled out on the bottom of the ocean.
Then, after millions of years, the ocean bottom was forced upward
in places forming the dry land, like Florida for example.
Then the yearly floods washed out new channels for the Little
Hatchet Creek, and we could clearly see the various layers in the banks of
the creek. The monstrous
teeth, as large as O’Malley’s hand, I had found in the nearby gravel
beds was further proof that this place had once been at the bottom of the
lack of enthusiasm shown by professional archaeologists with regard for my
arrowheads and fossils did nothing to dampen my interest in them.
The arrowheads were, to me, pure works of art while the shark teeth
and limestone fossils were also things of beauty and a reminder of the Age
of The Earth and the Grandeur of Time.
Baer was Carl’s foremost flight instructor and my strong mentor for
several years in the late 1930s. He was very alert to events in Europe and while many of the
adults I knew were in favor of “Peace At Any Price” with regard to
Europe’s War, The Duke saw that our involvement was inevitable and there
was no time to be lost in preparing for it. One time I was walking with
him near the hangar when I found a beautiful arrowhead where he had just
missed stepping on it. I
gathered it up and expressed great excitement over the find.
The Duke was less than enthusiastic and he used the occasion to
give me a serious lecture regarding vital matters.
The reason, he said, why we never saw any of the people who made
such artifacts was that Stone Age technology could not compete with modern
machinery. People like us,
who had guns and airplanes and all the rest, had essentially wiped out
those who could not adapt. Now
we were up against people in Germany and Japan and elsewhere who were dead
set onto wiping us out with their advanced technology, and we would surely
go the way of the Indians if we didn’t rise up to the challenge.
The Duke said that he didn’t know any worthwhile person who was
interested in rocks. Flying
and engines and lubrication and weather and navigation and everything to
do with flying was where the action was.
Those who devoted their time to such matters would be the winners
while those who spent their time with rocks and fossils would be the
few days later I swapped all of my arrowheads and fossils to Jimmy Tyler
on the school grounds and got in exchange a crystal set radio with
headphones and a number of car parts that he and his brothers had filched
from an auto-wrecking yard near their home. The radio did not work at first, but after considerable
fiddling with it I eventually managed to hear my brother play with The
Orange Grove String Band over the local radio station.
A few days later I was sick over my foolishness, but that was like
crying over spilt milk and I soon moved on.
I never held this misfortune against The Duke, perhaps because I
knew that he had only my welfare in mind, but also because he still had a
lot to teach me that I very much wanted to learn.
months later I was walking along the dirt road toward the hangar to visit
The Duke when I saw a large arrowhead some 40 ft away on the ridge of
earth across the ditch beside the road.
(The present day passenger terminal at the Gainesville Municipal
Airport is very near the place). The
ditch was full of water and heavy blackberry thickets on both sides made
getting to the artifact a non-trivial problem.
I went along the road until there was a break in the obstacles and
made my way back to the spot.
This piece, Figure 2, was a little over 4 inches
long and the point was unusually sharp when I picked it up. By the time I made my way back to the road a backwoods dirt
farmer I knew slightly came along and asked me, “What you got there,
boy?” “Arrowhead,” I
answered. “Lemme see
that,” he said, holding out his hand for it.
I handed it to him. “Naw,
boy.” He said, examining the piece, “that’s a Devil Stone and
them’s bad luck.” With
that he slammed the piece against his ax and threw the pieces into the
woods. Then he went on his
way. I was mad as hell, but I
was only 11 years old and not able to do anything about it.
I was vaguely familiar with this backwoods
superstition, but over time I came upon a fuller explanation of the
matter. Another version held
that arrowheads were formed where lightening struck the ground and might
even be a magnet for further lightening strikes… certainly bad luck for
the holder, if true. Still
another bit of lore told how they marked the spot where The Devil had made
water. The Devil was also widely given credit for prehistoric
fossils, like the dinosaurs, etc. There
were many who believed that the Earth could not be much older than 4000
years. A famous Minister and
Bible Scholar had once determined the exact moment of creation based on
Bible accounts, including the lives of the descendents of Adam & Eve
where the “begats” are listed. Those
devoted to this account believed that The Devil planted prehistoric
fossils and arrowheads for men to find with the intent of inspiring them
to reject outright, or at least question, the Biblical accounts of
I scoured the pinewoods and palmetto thickets
where this man had thrown the pieces of my arrowhead at every opportunity.
I finally found one piece a month or two later and when I examined
the broken cross section I was electrified by what I saw.
The center of the broken section, see Figure 3,
was a light purple color while all around the surface area the color was a
pale brown to a more or less uniform depth of roughly one millimeter.
It seemed extremely likely to me that the whole artifact had been
this purple color when it was new. I
had no idea how color in stone came about and my first idea was that
water, or something, had penetrated the surface and somehow bleached out
the color. I also considered
another possible effect based on my folks ongoing firewood project, both
for their own use and for sale to others.
They rarely, if ever, cut down a living tree because there was
always one or more in the woods near our home that had been killed by
lightening or blown over by high winds.
My mother and father would cut one or more of these trees into
stove wood length blocks using a crosscut saw and then split the blocks to
the right size using an ax. They
would then assign to me the task of stacking the sticks in an open
structure for the sun and wind to dry.
I had long since noticed how the sticks from the center of the tree
were always noticeably wetter than were the sticks from the outer edges.
I attributed this to the outward migration of the sap, mostly
water, and the subsequent evaporation of the moisture into the atmosphere
when it reached the surface. Perhaps,
I guessed, whatever is responsible for the purple color in my arrowhead is
likewise migrating to the surface and either being washed off there by
rainwater or simply evaporating into the atmosphere.
In any case, the appearance of the lightly colored strip of more or
less uniform width around the outside surface took a lot of time, and the
wider the strip, the longer the passage of time since the surface was
created and the tool was new. If
I could ever figure it all out, perhaps there was a way, after all, to
determine the age of arrowheads. I
fully realized that such a project was far and away beyond my capability
at the time, but perhaps that would not always be the case.
I put the piece of the arrowhead away in my room until, a few
months later, I found the other half.
Other matters took precedence for me now and this arrowhead was put
away and almost forgotten.
I started hanging out with Snubby Bailey and his
friend, Billy Hartman, around the time I turned 13 years old. Mr. & Mrs. Bert Reames had recently taken me under their
wing as an apprentice in their typewriter repair shop and I soon learned
that Snubby was a dishwasher at the coffee shop 2 doors away. I knew Snubby before this because my sister had a room in his
mother’s boarding house. Now
we had frequent occasions to meet in the common alley behind our places of
employment. Billy Hartman was
in Snubby’s Boy Scout troupe. I
joined the Scouts as well in response to Snubby’s urging and the 3 of us
started hanging out at Snubby’s house, before and after Scout meetings
at first, and then on a more regular basis.
Snubby’s older brother was an Eagle Scout and Snubby was intent
on this goal as well. In
order to move up in the ranks, one had to earn merit badges.
One way to earn a merit badge was to make a collection… stamps,
coins, leaves, insects, butterflies, seeds… almost anything.
To make a long story short, the 3 of us eventually
fell into arrowhead collecting and camping out on our own, without any
involvement of the Boy Scouts. Snubby
was still in the habit of documenting his collecting projects and urged
the practice onto Billy and me… with only limited success.
Said documentation included making a 3 x 5 inch file card for each
artifact identified by number and with an account of when and where the
artifact had been collected, an outline drawing, and any other relevant
later a college professor harangued me into resuming the practice and for
a very short while I tried, but I was too busy, or uninterested, or
whatever. By this time I had
recovered the item in Figure 2. and scribed #325 on it in sequence with my
effort at the time, but the numbers on my arrowheads are completely
meaningless. Even at my age,
77, I remember finding almost every one I own, the place, the time, the
circumstances, the weather and such, even though my short term memory is
the pitts these days. I’m
not at all sure what a card file catalog could do for my heirs or their
successors in ownership of my collection.
Hopefully this account of my interest in the age will be useful.
Who knows? Sorry ‘bout ‘dat… but not very sorry.
After a couple of years scouring the farms and
vacant lands around the edges of Payne’s Prairie we were always on the
lookout for new hunting grounds. One
time a fellow high school band member invited me to go fishing with him on
Biven’s Arm… an appendage of the Prairie, in his boat.
Rowing around the far side from his dock I saw a patch of ground,
perhaps 5 acres, adjacent to the water and almost devoid of vegetation.
I had never been to this part of the countryside before and
reckoned this place to be an ideal hunting ground for artifacts.
As soon as I had the opportunity I went to the land registry and
looked at the maps and ownership records there.
There was a 2-rut dirt road that I had never noticed before off the
highway leading back to the place. I
rode my bicycle there and met an old man sitting on his porch who answered
to the name listed in the registry. I
told him that I had noticed his farm while fishing on Biven’s Arm and,
with his permission, I would very much like to see if I could find any
arrowheads there. He was
quite talkative and seemed to be very grateful to have someone to listen
to him. “Yup,” he said,
“we used to call ‘em ‘Thunderbolts’.
What makes ‘em is where lightenin’ strucks the ground.
Yup. I used to turn
‘em over with the plow all the time when I started farmin’ here, but I
ain’t seen one in years. Them
University Professors used to come out here all the time and pick ‘em
up. ‘Thunderbolts’ is
what they used to call ‘em. Where lightenin’ strucks the ground is what makes ‘em.
But I ain’t seen one in years ‘cause them University Professors
done been out here and done got every one.
You can go on back there and look if you is a mind to, but you
ain’t gonna find none, ‘cause them University Professors done got
every one. ‘Thunderbolts
they call ‘em. That’s
‘cause they’re made where lightenin’ strucks the ground.”
I thanked him very much for this information and
walked back toward the water. Some
100 – 200 feet from his house I found the item shown here in Figure 4.
I found several more pieces there that day, halves
and fragments, and over the next year or so over a dozen whole, or almost
whole, arrowheads as well as numerous fragments and a number of potsherds.
I rarely saw the old farmer on these visits and I never shared
these finds with him because I had no desire to show him up as wrong in
any way. I noticed
right away that one wing of this arrowhead was broken, as well as the
shank, and the color pattern in the exposed section of the wing was
similar to that I had seen in Figure 3.
See Figure 5., below. I
assumed that the wing had been broken recently, perhaps by the horse or
the plow during the course of farming, while the shank had probably been
broken when the piece was more or less new.
I also assumed that the artifact had been the dark brown color seen
in the center of the broken wing when it was new.
It occurred to me that I could probably verify this assumption by
breaking the piece, but I was horrified by the very thought because I
still saw these artifacts as works of art to be taken at face value and
not as items with which to play out one’s scientific curiosity.
In 1953 I was a raw graduate engineer working at
my first job since college, at Bell Telephone Labs.
My assignment was to run, fetch, and carry for one Rudi Kompfner,
the inventor of the Traveling Wave Tube (TWT) and the Backward Wave
Oscillator (BWO). Rudi was a
very impressive person, indeed. He
once went to some effort to spell out for me the sin of “duplication of
effort”, as applied to the case of government financed research.
No one wanted to spend good money to re-invent the wheel, he said.
I’d had this lecture before in college, along with the counter
argument that many important discoveries had been made by revisiting old
and well-established theories. There was also the widespread doctrine that all new
knowledge, no matter how seemingly irrelevant at the time, would most
likely prove to be useful, if not vital, sooner or later. I was reminded
of the farmer who assured me that “them University Professors had done
got every one of them thunderbolts” off his farm.
I told Rudi of this incident and brought the two artifacts I had
showing surface related color patterns to show him.
I also related how a professional archaeologist had once told me
“there was no way to find the age of an arrowhead”.
It was my guess, however, that these color patterns somehow held
that secret. Rudi was duly
impressed, but he suggested that reducing the evidence before us to a
convincing evaluation of the age of the artifact was a daunting challenge,
indeed. A simple Cost To
Benefits estimate was not very inspiring.
Like, Who Cares? Even if I could see a clear path toward reducing the
evidence, which I emphatically could not, I was wholly preoccupied by more
pressing matters. My
supervisor was constantly on my case for results on the projects he had
assigned to me and I was anxious to learn everything I could about the
underlying principles of those matters.
The age of arrowheads would have to wait for yet another day.
The matter became a hot topic in my mind several
years later when I was working in the vacuum tube industry at Varian
Associates in Palo Alto, California.
The details are spelled out in “Finding The Age”, a memo on the
Web Site referred to earlier. The
production line for a Backward Wave Oscillator (soon to be made obsolete
by Solid State technology) had come to a grinding halt due to the failure
of a routine machining operation and it fell my lot to get to the bottom
of it. The problem arose when
the order of a brazing operation and a machining operation was reversed.
To be specific, traces of Sulfur had been alloyed into the raw
metal stock with the intent of making it easier to machine, but a brazing
operation in a Hydrogen atmosphere furnace facilitated the removal of the
sulfur from a surface skin and a consequent hardening of the surface.
Once we found the cause of the immediate problem the fix was
obvious. We simply returned
to the old way of doing things, but the revelation that Sulfur was
involved created a great furor. It
is deeply embedded in vacuum tube lore that certain elements, Sulfur,
Chlorine, Iodine, Zinc, etc., and etc. were devastating to cathode health
and/or vacuum integrity and I was assigned to find the rate at which
Sulfur could be expected to enter the vacuum from the Stainless Steel body
of the BWOs.
I was overwhelmed at first, but a fellow Varian
employee, one Lewis Hall, a young man with a recent PhD in Physical
Chemistry, became my coworker and mentor on this project.
He derived Fick’s Laws of Diffusion for me (click on Fick’s
Laws at the website referred to earlier for a complete discussion) and I
noticed right away that these were identical in form to The Heat Equation. Lew pointed out that this was because the Heat Equation
describes the scattering (by diffusion) of heat energy in the form of
atomic motion throughout a solid, liquid, or gas in a manner exactly
analogous to the diffusion of trace atoms moving throughout a solid,
liquid, or gas by a process he called “Thermally Activated Random
The project came down to the measurement of the
diffusion parameters (the binding energy and vibration frequency) of
Sulfur in solid solution in the Stainless Steel we were using.
I prepared the samples and fired them at various temperatures for
various times in a Hydrogen atmosphere furnace. I also served as the machinist for the project, carefully
removing a thin skin from the surface of the various samples, before and
after firing, and taking the turnings to the chemistry department for
analysis. The chemists
determined the concentration of Sulfur in the chips, before and after
firing, while Lew analyzed the results using Fick’s Laws.
The data matched the theory remarkably well and we were soon in
possession of the diffusion parameters that proved to be independent of
the temperature, as well as the Sulfur concentration, as close as we could
We were concerned at the outset that perhaps the
diffusion parameters might depend significantly on the amount of Sulfur
present. Certainly the
hardness and/or toughness of the steel was so dependent, as I could
readily tell from the sound of the cutting operation as I removed the skin
for the chemists. But the
data was clear… if there was any such effect it was very minor.
I brought my arrowheads to Lew after this job was
over and asked his opinion regarding our ability to determine the age of
them in the light of what we had just done. He guessed that this would be
“a piece of cake” if we had the time and the money, but he was also
quick to point out some complications we might well run up against.
To begin with, he pointed out that the material we were looking at,
the stone, was much more like a glass than a solid and that the external
environment, like the relative humidity, could be an important factor.
For example, suppose the moisture in the air was slightly acid and
altered the glassy structure of the stone near the surface.
This might have a significant effect on the color independent of
the concentration of the trace atoms we presumed to be responsible for
those colors. We both knew
that the color of everyday glass ware was critically dependent on the
concentration and species of trace atoms dissolved within, but the details
of the physics was not clear to either of us.
Since we had no way to know how the environment might have changed
over the time period in question, there could be considerable uncertainty
in the results if this was an important factor.
On the other hand, he said, the color patterns we were looking at
were probably very complex and this could ultimately work to our advantage
once we had a complete theory in hand.
Suppose, he suggested, that the color was a result of several
factors such as the glassy structure, the species of trace elements, the
external environment, relative humidity, temperature, acidity, etc., and
etc. It would be a major
chore, to be sure, to come up with a theory for all of these factors, and
their interactions with each other, but modern technology was full of such
complex situations that had been fully mastered.
In a worst case scenario, Lew suggested, a complete theory could
very well lead us to a very narrow range of time lapses consistent with
all of the findings. On the
other hand we might also find that the physics was fairly simple, as we
had found in the case of Sulfur in Stainless Steel.
Lew and I took the arrowheads and our speculations
to nearby Stanford University and the Archaeology Department there.
These people were very interested and suggested that if we could
come up with a scheme to routinely and reliably measure the age of stone
tools that would be a very valuable breakthrough event for them, indeed.
The physics, however, was wholly outside the range of the expertise
of anyone in the department and, most likely, in the whole of archaeology.
On the way back to Varian, Lew and I reckoned that there would be
no enthusiasm on the part of management there for the kind of study
necessary to yield results. Certainly
we were both far too busy working on vacuum tube production yield problems
to get involved. The age of
arrowheads would have to wait for yet a while.
In 1961 I transferred from Pilot Production to
Central Research. CR had
recently embarked on a wide-ranging program to develop and exploit certain
“exotic” materials such as Yttrium-Iron-Garnet (YIG), Lanthanum
Tri-Fluoride (LaF3), and all manner of Semi-Conductors.
During the course of a casual discussion with one of the people I
played bridge with I learned of his project to measure the magnetic
properties of YIG, which was being produced in one of the labs on site.
It struck me that there was a simpler way to go about this and, to
make a long story shorter, I was invited to join CR to develop the
instrument I had in mind. This
effort was successful and I soon found opportunities to work on other
instruments to measure various properties of materials, some “exotic”
and others not so exotic, some even mundane.
I was also given some supervisory duties over the CR Machine Shop
and Electronics Shop. These
facilities built hardware and electronic equipment in support of the
various research projects. There
were more or less a half dozen PhD Senior Scientists in CR with
independent, but somehow related, projects underway.
Most of these had to do with Solid State Physics, Lasers, and
One of my first “Properties Of Materials”
instrumentation tasks was to measure the thermal conductivity of LaF3.
I had always been interested in Heat Transfer as one of the central
problems that must be seriously addressed before any vacuum electronics
device can become commercially viable.
As J. R. Pierce (a major luminary in the vacuum tube firmament)
once put it, “those who solve the Wave Equation tend to get all the
glory while those who solve the Heat Equation are the ones who make it all
work”. Major number
crunching computer power had recently become available to us in CR in the
form of FORTRAN programming as well as Tymeshare IBM 360 Basic, so I was
able to perform experiments on fairly complex thermal networks and use the
computer to reduce the data and come up with the desired results by
implication. In the specific
case of LaF3, I constructed an instrument with two Copper blocks, one a
heat source and one a heat sink. I
could measure and record, quite accurately, the temperature of each copper
block and, even more accurately, the temperature difference between them.
I could then insert a sample of LaF3 of almost any simple shape
between the blocks making thermal contact using a proprietary ‘thermal
grease’, heat one of the blocks slightly with a small torch, and then
record the cooling transient. There
were, of course, many different heat paths and at least several
impediments to heat flow between the two copper blocks, in addition to the
LaF3 sample, but once I had constructed a complete computer model of the
whole network it was fairly simple to sort out all of the relevant
parameters and arrive at a completely independent and reproducible value
for the contribution of the LaF3 alone.
Before claiming victory I also used this setup to compare my
results with some generally accepted values for the thermal conductivity
of some common materials such as Copper, Iron, Tungsten, Sapphire,
Beryllium Oxide (BeO), etc. I
was very gratified by the results. The
only material I was unable to characterize at all was Diamond.
The thermal conductivity of Diamond is very high indeed and unless
a favorably shaped sample is available the true value is apt to be lost
among the various inevitable uncertainties in such a measurement.
The complexity of this problem struck me as quite
similar to that of a worst-case scenario in sorting out all of the
important effects in determining the time involved creating the color
patterns I was looking at in my arrowheads.
Instruments to measure the dielectric and/or
magnetic properties of various materials were soon to follow. The coefficient of thermal expansion was of considerable
interest in some cases and a Laser Interferometer due to Sol Miller became
available early in the game and proved useful to this end.
Perhaps the most useful instrument we had in CR
for studying the basic structure of semiconductors and other solids was
the Laue Camera. This is a
relatively simple device although a detail description of its operation is
far beyond the scope of my argument here regarding the age of stone
artifacts. Abe Kaufman, who
held a PhD in Solid State Physics, was its master and he rejoiced in
explaining how it worked and what wonderful stuff one could learn from it.
When I was a graduate student in college I taught a course in Power
Transmission and was more or less familiar with the propagation of
electromagnetic waves in one and two dimensions and the nature of
constructive and destructive interference as between incident and
scattered waves. In the Laue
Camera we have a source of X-Rays with a wavelength on the order of 1
Angstrom (1E-10 Meters). This wavelength is comparable to the distances between the
atoms in most solids. The
X-Rays are made and confined within the source device except for a long
thin hole a fraction of a millimeter in diameter.
A highly collimated X-Ray beam emerges from this hole and is
directed toward a sample of the solid under study.
The atoms of the solid scatter the individual X-Rays in all
directions, but if the atoms are arranged in orderly 3-dimensional arrays,
as they are in most solids, the reflected X-Rays will reinforce each other
in phase in certain specific directions.
In all other directions the X-Rays interfere destructively and are
not detected. A photographic film sensitive to the X-Rays is placed where
it will be exposed only in an array of small spots, images of the
collimating hole. Abe was
able to look at such a film, a “Laue” as he called them, and tell at a
glance the crystal structure of the solid.
He explained to me that there were only a small number (14 if
memory serves) of possible crystal structures with names like Cubic, Body
Centered Cubic, Face Centered Cubic, Hexagonal, Spinel, etc.
(The DNA Double Helix is apparently one possibility).
By measuring the angles and distances between the spots on any
given Laue plate, Abe could tell the absolute distances, in Angstroms,
between the various planes in which the atoms had arranged themselves.
I gathered that a wide range of the properties of a solid could be
determined from its crystal structure.
I also learned from Abe that glass did not have a
crystal structure. I was
keenly interested in scientific (as opposed to artistic) glass blowing
ever since my days in college and took every opportunity I could to become
proficient at it. My first
mentors in glass blowing told me that glass was not a solid, but rather a
very viscous liquid. Two
simple demonstrations were offered to emphasize that conclusion.
In one case a horizontal length of glass tubing about ½ inch in
diameter and 4 ft long was supported at each end for several days.
It was then removed and placed on a flat surface.
When rolled along this surface it was quite apparent that the
tubing had a slight, but observable, bow in it that was not apparent at
the start. Another
demonstration had to do with the proper way to break glass tubing to the
desired length. A Diamond or
Tungsten Carbide tool was used to scratch, or score, the tubing at the
place where a break was desired. Applying
a sharp bending moment on either side of the score would, if done right,
result in a clean break at the desired place.
An experienced glass blower would, without thinking about it, pass
his thumb over the place where the glass was scored before applying
pressure. Failure to do this
would usually result in a less than clean break.
The explanation offered to me was that the original score ruptured
the bonds between the atoms of the glass to a slight, but significant,
depth below the surface. Left
alone the glass would quickly heal itself, but passing the thumb over the
score, particularly after the thumb had been dampened with the tongue,
would allow some moisture to penetrate the rupture and prevent or deter
the healing. The deeper the
rupture the weaker the bonds and the glass would break cleanly where
desired. One of my tutors had
worked for years in the Neon Sign business before becoming a Master
Scientific Glassblower and he told me that most “tube benders” learned
this trick of the trade by osmosis, from seeing others do it, as opposed
to any specific guidance.
Further evidence of the liquid nature of glass was
offered to me during a recent discussion of this matter.
A tour guide had told my informant last summer while he was
visiting an ancient cathedral in Europe that the Holy Figures in a stained
glass window were sagging slightly, but perceptibly, due to this
characteristic of glass.
Another demonstration of the liquid nature of
glass may be found in the observation that broken glass may have some very
sharp edges when the break is fresh, but over time the edges become
noticeably less sharp. I
am familiar with some archaeological evidence to the effect that Obsidian
(a volcanic glass) knives had been used to open the skulls of some
Pre-Columbian people in Latin America.
The patients (victims?) had survived, as healing of the bone was
evident. The lore included a
statement to the effect that freshly broken Obsidian produced some of the
sharpest edges known. The
evidence for this must be considered anecdotal In lieu of careful study,
but in the early 1990s I served for a short while as a mentor to a college
student working on a degree in Forensic Science.
He was interested in developing a procedure for determining how
recently a piece of broken glass found at a crime scene had been broken.
The procedure we discussed was first to determine the viscosity of
the glass as a function of temperature and, from this information,
determine the bonding energy between the atoms making up the matrix of the
glass. We should then be able
to calculate the rate at which atoms at a sharp edge would migrate, by
self-diffusion, away from a sharp edge and toward the thicker parts, thus
rounding and reducing the sharpness of the edge. We proposed to measure the “sharpness” of an edge by
measuring the force require to sever a standard fiber… such as a strand
of spider web.
We also discussed another property of glass that
might be useful to a forensic scientist.
When light passes through glass any local stress tends to cause the
plane of polarization of the light to rotate.
The angle of rotation is roughly proportional to the degree of
stress. A polariscope
to observe this phenomenon is a basic instrument to be found in every
laboratory where scientific glassware is made. The polariscope is a very
simple device with two polarized windows on a common axis placed several
inches apart. Anyone who has
ever seen a 3-d movie is familiar with the polarized glasses that are
required to enjoy the full effect. The
screen is illuminated with two superimposed images.
The light is polarized so that one image is polarized 90 degrees
away from the polarization of the other image.
One window of the glasses will pass light of only one polarization
while the other window transmits only light polarized 90 degrees apart. Many people, once they get home, have placed the two windows
one against the other and noticed that the pair can become almost opaque
when the angle between the orientations is right.
The polariscope in the glass lab works on the same principle.
An incandescent light behind the first window emits photons of
every polarization. The first
window passes selectively only those photons of one polarity.
If the second window is orientated 90 degrees from the first, most
of the photons will be blocked there and the view looking into the second
window will be dark. When the
glass blower places his work between the windows he can readily see those
regions with localized internal stress.
An annealed piece of glassware will appear dark in this case. The
novice glassblower may soon notice that almost any piece of glass will
cause the polarization of light passing through it to shift perceptibly
due to any small pressure he may apply by hand.
The polariscope is a very sensitive instrument.
the course of glass blowing the heated portions are rarely allowed to cool
slowly after being worked and the finished product is apt to have a lot of
local stresses. These can
make the item more fragile during normal use than if the glass is free of
local stress. Thus an
annealing oven is also a basic requirement in a glass lab. When the glass
blower is done fashioning a piece of glassware the work is normally placed
in the annealing oven. In the
case of Pyrex type glass the oven temperature is brought slowly to around
400 DgC and then allowed to cool slowly to room temperature, the entire
cycle lasting perhaps 6 – 10 hours.
Most glass used to make vacuum tubes and chemical ware is worked
into shape at around 800 – 1000 DgC.
At the annealing temperature the work will not sag perceptibly, but
on the atomic scale each atom will find a location with respect to its
neighbors where the forces of attraction and repulsion are more or less in
balance and the energy stored in stress is a minimum.
When examined in a polariscope the stress free condition can be
In addition to having very sharp edges, freshly
broken glass has considerable localized stress on and near the fresh
surfaces. The forces on the
atoms on the freshly broken surface are greatly out-of-balance as compared
to the situation before the break. This
can readily be demonstrated by observing the polarization of light
reflected from a freshly broken surface.
As time goes on, however, the surface atoms will migrate (by
thermally activated random walk… self diffusion) into nearby positions
where the total stress energy is again minimized.
The time required depends on the atom-to-atom bonding energy, the
local viscosity, and the temperature.
Overnight in an annealing oven would probably do the trick, but at
room temperature at a crime scene my intuition tells me that several days
or weeks or perhaps months would be required before the surface stresses
would be undetectable. To my
knowledge, this research never got beyond the discussion stage as the
young man failed to show up for a regular appointment with me and never
answered any of my subsequent calls.
In the mid 1970s a man came to my office where I
had some arrowheads on display. He
invited me to his home to see his collection, which was spectacular,
indeed. Several walls were
covered with beautiful specimens numbering well over 2000 by my estimate. Most spectacular as well were the brilliant colors and near
perfect shapes. My host was a
geologist working for the US government and he had collected rocks from
around the world. His garage
was full of boxes of these rocks, along with a diamond saw and other gem
making tools. He had made, as
a hobby, all of the arrowheads on display, but not using the methods used
by the aborigines. He
selected from a small bin several blanks cut to the rough outline of an
arrowhead and then took me back to his indoor workshop where he could
finish the piece while watching TV or listening to music.
The most basic tools here were several items resembling large
nails, tipped by Diamond or bits of Tungsten-Carbide, as well as some
rubber sole ‘footies’, such as those I had seen people wear around a
swimming pool. I was about to
get my first lesson in how arrowheads might be made for sale to the
tourist trade in the North Western USA. The blank was placed on the footie, which has just the right
hardness-softness to allow the removal of a single flake without excess
shock to the rest of the piece. Using
a pointed carbide tipped nail, my host applied pressure to the edge of the
blank and a narrow flake in length roughly the width of the blank was
produced. After a dozen or so
flakes were thus made, he removed the work from the footie and dumped the
flakes into a small tray. He
mentioned that these flakes were razor sharp and that he had lost well
over a pint of blood while learning these techniques.
The blank had taken on the look of a real arrowhead where the
flakes had been removed. Perhaps
10 – 15 minutes from the start, my host had a finished piece that would
fool almost anyone except for the fact that the edges were very sharp and
all surfaces were brightly colored.
He said that professional forgers for the tourist trade had a
number of ways to “age” their works.
He preferred the beauty of the raw works and did not age them, but
he showed me a homemade rock tumbler he used for other purposes such as
polishing gemstones. It was a
simple device using a small electric motor to drive a shaft made of
concrete re-bar. An old tire
suspended on this would rotate at just the right speed for tumbling rocks
in a slurry of slightly abrasive sand.
Before I left his hospitality, my host gave me a blank and the
necessary facilities and I made the item shown as #3 in Figure 7., below. The edges are still slightly sharp today in 2004.
A client, who told me that she bought them for $1 each at a
roadside stand in South Dakota, gave the other items, #1 & #2 to me.
While the sharpness of the edges and the general
patina on the surface of stone tools may enable us to distinguish
counterfeits from the real thing, these factors are of little or no use
when it comes to determining the passage of centuries.
Or such is my opinion. Nevertheless
we cannot know too much physics when it comes to sorting out all of the
factors that may be at work in the formation of “weathering” rinds.
The surface chemistry, for example, is apt to be strongly dependent
on the surface stress energy. I
can imagine that the external environment, the rainfall, the soil pH,
decaying vegetation, etc. could alter the structure of the glassy surface
considerably over the first century or two with more vigor than I would
suspect after the surface stresses had annealed themselves.
When Lewis Hall and I first considered the
surface-related color patterns observable in two of my arrowheads, we had
just finished a study of the diffusion of trace elements in a solid by the
process of Thermally Activated Random Walk, following Fick’s Laws.
We assumed that something similar, although not necessarily an
exact analog, was responsible for the color changes we were looking at in
the arrowheads. We were both
aware of the glassy nature of the arrowhead material, but we guessed that
diffusion in glass was probably quite similar to diffusion in solids…
i.e. characterized by an activation energy and a frequency factor.
We were also quite familiar with the fact that faint traces of
elements, mostly metals, were universally used to produce color in glass.
Cobalt, for example, made some glass blue, while Chromium made some
glass red, and Uranium made some glass green.
We were also familiar with fluorescence.
In RADAR school in the US Navy, I learned that oscilloscope CRTs
(Cathode Ray Tubes) used various ‘phosphors’ to produce various
display features. For general
use we used a CRT with a green ‘low persistence’ screen.
The screen emitted green light when a stream of electrons (a
cathode ray) struck the phosphor. The light intensity decayed very rapidly as soon as the
electron beam was turned off. The
CRT used to display RADAR targets used a ‘high persistence’ phosphor
screen… roughly yellow in color. Any
spot excited by the electron beam continued to give off light long after
the beam was turned off. Those
screens also tended to glow in the dark long after all CRT power was
turned off. Fluorescent lights as well as an electron beam could also
excite the glow. Quite
clearly, the pattern of colors in my broken arrowheads could arise from a
variety of physical effects, most having to do with the properties of the
material (the glass) of which the arrowhead was made as well as the
species and distribution of trace elements.
A great deal of information is thus available to us if we could
study the fluorescence and the persistence of any light emitted by a
sample of rock found at an archaeological site when it was made a target
in a cathode ray device.
I have discussed this subject with several
professional archeologists over the years and I have heard the term
“weathering rinds” more than once.
It is quite apparent that I am not the first person to observe
these color patterns. It is
also quite apparent that they are widely believed to be due to the
external environment far more than any physical effects like random walk
within the artifact. This
being the case, it is easy to see why there might be a lack of enthusiasm
for any serious study of the phenomenon with the goal of determining the
age. The weather, the
climate, the pH of the soil in the precise locality where an artifact is
found is not knowable over any extended period of time.
At least it was not knowable before serious tree ring studies have
shed much light on the world’s climate over the past 7000 years.
(The microclimate of any locality is still apt to be a deep
mystery). Thus, if the
observed color patterns are exclusively a result of external factors, any
such study as I may propose is apt to be fruitless.
This was made clear to me early in the game when I
was introduced to the phenomenon of “Obsidian Hydration”. Obsidian artifacts tend to exhibit “weathering
rinds” under close observation. I
was once taken to a laboratory where a number of thin slices of obsidian
taken from several arrowheads were being studied.
These slices were perhaps 0.25 mm thick and were quite transparent.
The laboratory was well equipped to study, in fine grain, the
optical properties of these samples as a function of depth below the
technician, who seemed to be quite knowledgeable, explained to me that her
technique was useful for determining only the “relative” ages of
artifacts found in the same locality because of weather and other
variables (like soil pH) at distant sites.
She was wholly non-receptive to the idea that trace elements moving
outward by Thermally Activated Random Walk could possibly be a factor.
She was unable to give me an account of either the physics or
chemistry of Obsidian Hydration and I was never able to find any such
I was exposed to several lectures on the general
subject of Scientific Research during my college years. One of my professors in graduate school went to some effort
over an extended period of time to spell out his philosophy on the
subject. He drew an analogy
between discovery in the laboratory and discovery over land and sea.
Before Lewis & Clark made their famous trek over the unexplored
lands of the Northwest US, for example, they made a thorough study of the
maps and notes of those who had gone before.
Likewise, the alert investigator in matters electronic would be
well advised to study the writings of those who had been there and
published before he did anything on his own.
The people paying the bills would not be pleased to learn that they
were paying for re-inventing the wheel.
Duplication of effort be bad… very bad.
When I started working for Rudi Kompfner he was
intent on building an electron gun to produce a well-behaved hollow
electron beam. After he had
explained the benefits of such a device and his ideas for making it a
reality, he gave me a very rough sketch of what he had in mind with a few
critical dimensions and assigned the task of filling in the details to me.
I was to make the parts drawings and supervise their fabrication in
the machine shop and their assembly in the clean room.
After discussing the assembly details with George Helmke, the
Master Tube Tech, and submitting a number of drawings to the shop, I got a
copy of Pierce’s book on Electron Beams and started studying it.
Kompfner took note of this and during a coffee break we got into a
general discussion of his philosophy of research.
He told me of his first day on the job after he had been hired by
an architectural firm… his degree being in architecture.
His boss gave him a rough sketch of a structure and asked him to
piece out the details and make working plans for its construction.
After studying this assignment he sat looking at a blank vellum on
the drafting board for too long. An
old hand, sensing his dilemma, came over and suggested that he start by
drawing a baseline. This
done, the rest of the design seemed to gradually fall into place more or
less naturally. “Do
something”, he advised, “even if it is wrong.
The worst approach is to do nothing.”
Science, he said, is a self-correcting discipline.
Nature will give you the bad news soon enough.
Such is my experience as well.
He then told me his version of a story I’d heard
previously from others, about how he came to invent the TWT. The group he
was working with was developing and building Klystrons and Magnetrons for
wartime RADAR applications. In
those days Magnetrons were high power microwave vacuum tubes used mostly
as RADAR transmitters while Klystrons were useful in RADAR receivers.
Both were very narrow band devices operating at a single frequency
unless some facility had been incorporated to deform the vacuum envelope
somehow, by way of tuning it. This
made it relatively easy for an enemy to determine the frequency at which
you were operating. He could
then transmit back to you a “jamming” signal and thus defeat your
RADAR. The electronic
countermeasures war was underway. What
was needed was a “frequency agile” system.
The ideal system would be capable of changing the frequency of each
pulse while the receiver listening for echoes would track at that same
frequency. The enemy would
require several such incoming pulses before he could determine the proper
jamming frequency. By that
time, however, it would be too late.
R.K. recognized that an electronic device capable
of transmitting and receiving microwave signals over a wide band of
frequencies would be a very useful innovation and he began speculating to
himself how such a device could be made.
The most broadband device he knew of was a 2-wire transmission
line. If he could somehow
send an electron beam through the electric fields surrounding such a
transmission line, then perhaps something interesting might happen.
Unfortunately electron beams were not the right shape.
Perhaps if he wrapped the 2-wire transmission line in the form of a
helix and sent an electron beam down the center he might observe some
useful interaction. He ran this idea past his betters and was told that he was
crazy. These worthies had any
number of reasons why such an idea was utter garbage.
But the more he thought about it the more he was convinced that
something interesting … he couldn’t say precisely what… was apt to
take place. He quietly built
a crude experiment using a scrap oscilloscope gun to make a very crude
electron beam and he focused this beam down a crudely made helical
transmission line. He applied
a small signal into one end of the helix and observed a much larger signal
at the opposite end. This “amplification” was observed over a band of
frequencies as wide as the range of his test equipment.
The implications were nothing short of stupendous and a new
industry was born, yet it was some time before the best theoreticians were
able to come up with a mathematical model to partially explain what was
R.K. went to some effort to tell me that he was
devoted to “Intuition” as a most powerful and vital attribute in
anyone aspiring to be an innovator in any technical field. Even after the
math people were able to tell him what was going on in the TWT, he was
much more comfortable with his intuitive understanding of the matter.
Intuition, he said, was mostly a consequence of having worked out
all of the simple problems related to a subject of interest. The solutions to the more complex problems could not then be
too far afield from this familiar territory.
I’d had a similar series of lectures from Jim Ebers, one of my
thesis advisors at Ohio State. Jim
was now at Bell Labs as well and I went to visit him several times while I
was working on Kompfner’s hollow beam electron gun.
Jim taught the course on Network Synthesis at OSU and he had
suggested more than once in class that many, if not most, synthesis
problems had no mathematical solution while intuition based on having
solved all of the simple network problems was perhaps the best way to go
in this field.
In due course the Hollow Beam gun was ready for
test. I reread Pierce after
this data was taken and found that his arguments meant one helluva lot
more sense to me afterward than they had the first time through. So much so that I made it a general principal, when embarking
on any new investigation, to do as much as I possibly could on my own
before studying the literature. I
found that the literature was a lot more meaningful and illuminating this
way. In some cases I was able
to avoid serious errors that the author had made before proceeding,
unaware that he was going down a dead end.
I was given another assignment before Kompfner’s Hollow Beam Gun
project was abandoned. I
don’t know the details, but another scientist in the group was also
working toward the same goal and may have had success first.
In any case, developments elsewhere eventually made both efforts
obsolete, or so I was told later. Such
is the nature of R&D.
The matter of sorting out all of the complex
physics that might be going on in weathering rinds may be as complex as
any problem in vacuum electronics, but my intuition tells me that it
ain’t so. So, what would I
tell some filthy rich patron who had nothing better to do with his money
than to fund scholarships for a bevy of graduate students intent on
earning the PhD in Material Science to get to the bottom of the matter?
To start with, I would want a well-equipped
Materials Laboratory staffed by a team of experts like those I worked with
in Central Research in the 1960s. This
would include the following people, or their like numbers, to serve as
mentors to the grad students:
Abe Kauffman, expert in Laue X-ray analysis and crystal structures.
Bob Fairman, chemist supreme.
Dewey Atchley, generalist with common sense and wide experience in
solid state and atomic physics.
Marcel Muller and Arden Sher, experts in Quantum Mechanics,
Fluorescence, and spectroscopy.
John Helmer, Auger Spectroscopy.
The grad students would, of course, do all of the
tedious legwork. There is no
cheaper source of labor than Graduate Students.
For starters I would need a supply of raw material
samples of the kind my arrowheads are made of.
The arrowheads themselves would not do, because I still see them as
works of art and I would need to know precisely what I was looking for
before I could bring myself to perform any experiment that might deface
them in any substantial way. After I retired from the vacuum electronics
industry at the end of 1996 I made a pilgrimage to Florida to visit
relatives and old friends and the old haunts where Snubby and Billy and I
used to find arrowheads. Lawns
and housing covered many of the sites while others were posted with
warnings of the danger of herds of wild bison.
I learned from the locals that the bison are wholly non-existent,
although flocks of wild turkeys and armadillos, unknown before 1950, are
quite common now. On or near
Jackson’s Farm, at the East edge of Payne’s Prairie, I found several
collectable artifacts along with numerous fragments that were, most
likely, debris left over from tool making.
There is no other way I can imagine to account for the abundance of
such material at this place. Limestone quarries and sinkholes where one
can find Chert nodules weighing some 50 - 100 pounds, more or less, are
common in the area and such objects are often found where the aborigines
probably left them as raw stock for making stone tools.
Figure 6. shows a broken section of a typical
sample of the Chert fragments to be found wherever arrowheads are found
around Gainesville. This one
is from Jackson’s Farm. It
is roughly 1-1/2 inches across and shown roughly full size in this cross
section. The “weathering rind” is clearly evident.
Almost every other fragment found at this site shows something
similar when broken. These
pieces have no artistic value to me and are thus ideal samples from which
to start taking data. For a
start, I would probably prepare a few thin slices through the cross
section shown as well as a number of cubes roughly 1 millimeter per side
from throughout the sample, being careful to keep a record of where, with
respect to the surfaces, each sample came from.
[Close examination of the rinds in Figure 6. shows
that they are not the same thickness on both sides.
This may or may not be consistent with the weather or climate
theory. It is quite
conceivable and perhaps likely that one side would be exposed directly to
the sun while the opposite side would be in contact with the cool earth
for long periods of time. Just
how this would affect the weathering rinds, assuming whatever scenario,
would need to be taken into account and just how this factor might play
out is not obvious to me at this time.]
“What kind of data should we take?” one may
ask. My intuition tells me
that the central regions of the sample shown in Figure 6 are similar, if
not identical, to the bulk of the Chert nodule from which is was taken. By some accounts from people bent on making and using
stone tools the way they imagine that the early people did, a wide variety
of fragments, as to sizes and shapes, result when a large nodule is
properly struck by a heavy cobble or hammer stone.
Many of the fragments have razor sharp edges and some are useful,
as is, for some tasks around the campfire without further work.
Film footage of archaeologists and their students butchering large
and small animals with such fragments have been shown on TV.
In some cases these people go on to demonstrate how arrowheads and
other tools can be made from the various fragments using small cobbles,
bone, or antlers to apply blows or pressure to remove flakes.
Some hobbyists have become sufficiently skilled in the “flint
knapping” arts to command premium prices from collectors for their work.
In one account someone gave me, an artifact forger made a fluted
“Folsom” Point for a collector with some credentials as an expert who
paid him $10,000 more or less. But
Chert nodules, I am told, are formed on the ocean
bottom in deep deposits of limestone… an aggregate of the shells of
clams, oysters, and other shellfish.
The varieties of such formations are almost endless, as I have
gathered by talking to several “Gemologists”.
Chert, Flint, Agate, Jade, Jasper, etc. and a wide variety of other
terms may be heard when experts talk about the raw materials from which
arrowheads are commonly made. The
distinctions may, or may not, be subtle.
In any event, these glassy formations suitable for making stone
tools tend to accumulate small traces of the various elements, metals
mostly, whose salts are often found in seawater.
Magnesium, Potassium, Bromine, Iodine, Boron, Iron, Aluminum…
perhaps the entire Periodic Table of elements… are often mentioned as
trace elements to be found in sea water as well as in Chert, Flint, etc.
Obsidian is also a very important raw material useful for making
stone tools. This glassy substance is of volcanic origin and may have
trace elements other than the ones commonly found in Chert, etc.
The glassy matrix can, most likely, be
characterized as to its atomic structure and chemical composition into one
or another familiar Gemstone types. Abe
K. could probably tell which just by looking.
The refractive index, viscosity, thermal conductivity, dielectric
constant and loss tangent, thermal expansion coefficient, etc., as well as
some other basic properties could, perhaps, be found in published tables
of such. The next step, after
characterizing the samples, is to study how these parameters vary with
time and temperature, as well as various external environments.
Recall that Lew Hall and I determined the binding energy and
vibration frequency of Sulfur in Stainless Steel by taking thin samples
from the surface of larger pieces before and after they had been fired in
a Hydrogen furnace at various temperatures for various times, and finding
the amount of Sulfur lost in each case by chemical analysis of the
shavings. In the case of millimeter cubes of stone, perhaps some
optical means could be devised to measure the loss of trace elements as a
result of heating. In the
case of thin sections perhaps the transparency with respect to
displacement from the surface could be measured as a function of
temperature if we have a large enough sample to begin with.
The sample needs to be large enough to minimize surface effects
Perhaps 30 years ago I saw a TV presentation on
PBS regarding the work of an archaeologist studying Stone Age trade routes
in Europe. He was compiling a
“Flint” database… my
characterization. I gathered
that all “knappable” rock formations useful for tool making could be,
in his mind at least, classified as “Flint”.
He had made some effort to take “fingerprints” of various
Flints in terms of their colors as determined by the relative abundance of
the trace elements trapped within. Using
his intuition based on experience, he strongly suspected that a certain
tool found in one location was made of a Flint from a certain quarry
familiar to him some distance away. A
comparison of the color and trace element distribution as between the
artifact and the rocks from the quarry made for a compelling case in
support of his intuition. His
thesis, as I understood it, was that high quality Flint was traded all
across Europe by stone age people and that it should be possible to take
trace element fingerprints of at least the major known quarries and match
them with the trace element fingerprints of tools found elsewhere and
eventually map out some trade routes.
A comment toward the end of this presentation caught my attention. He said that the trace element fingerprint taken from the
center of a tool was apt to differ from the same fingerprint taken near
the surface of the tool. This
effect should be taken into account when someone was trying to compare
fingerprints with the database he was hoping to develop.
I made some telephone calls to get an address for the people who
had produced the video and wrote to them suggesting that further study of
the trace element distribution with respect to the surface of a tool
could, most likely, lead them to the age of the artifact.
I never got a reply. Nor
have I ever heard of any follow up with regard to the trace element
I was particularly encouraged while watching this
footage to learn that someone had gone to so much trouble to try and
understand such matters. In
particular I was encouraged to learn that there are people, other than
myself, who love to solve tough problems.
Truth be known, I am far less interested in the actual age of these
artifacts than I am in the general problem of a fundamental understanding
of what is going on with respect to these “weathering rinds”.
I am, of course, very interested to know the history of my species,
but the more general matter of problem solving for its own sake is my
underlying passion. My intuition still tells me that Thermally Activated
Random Walk with respect to the trace atoms that give rise to color will
prove most fruitful. My
intuition also tells me that degradation at the surface by external
factors will probably have an effect on the diffusion rates near the
surface, but there should be plenty of information further toward the
interior of the artifact. And
if it turns out that external factor are important then my intuition tells
me that that there are probably enough variables to lock down an elapse of
time consistent with all observations there as well.
The item shown in Figure 8., below, was found at
the same site as the specimen shown in Figure 6.
I see no evidence of “weathering rinds” in this piece.
What I see here is pure diffusion from a steady source of “red
stuff” on one face to the other 2 faces where escape to the external
environment takes place. I
have found a number of rocks with similar “veins”. I once asked a geologist how such formations came to be and
his answer made good sense to me. As
I understood him, many sedimentary aggregates tend to fracture when they
are still soft and foreign material moves in to fill the gap.
Then as the sediment hardens and becomes rock hard, the material in
these veins is trapped. When broken by a blow from a cobble, the break often follows
one side or another of the vein. In
this case it seems to me that the piece was broken so that the vein stuck
to the piece shown here and serves to keep the concentration of the “red
stuff” more or less constant at the face to which it is attached. If this scenario is responsible for what we see here it
should be relatively easy to determine how long the color pattern we see
has been in formation… once we measure the heat of diffusion of whatever
the “red stuff” in the glassy matrix is.
This parameter should not be too difficult to measure as there is
enough raw stock here to make a number of test samples for treatment at
elevated temperatures to accelerate the processes.
The matter of escape from the surface by a trace
atom reaching it deserves some mention here.
In the case of Hydrogen and Nitrogen, H2 and N2, in solution in
metals we find Seifert’s Law to hold true.
Seifert’s Law holds that the solubility of diatomic gases in
metals is proportional to the Square Root of the pressure in the gaseous
phase. This is true because
only atoms penetrate the bulk of a metal and equilibrium at the surface
comes about when the diatomic gas molecules are disassociated at the
surface to allow the individual atoms to find a place for themselves in
the metal lattice below the surface.
An atom of H1 or N1 diffusing to the surface must pair up with
another atom on the surface before recombination and desorption as a
molecule into the gas phase can occur.
The bonding energy between an atom of these gases and the metal
surface is so high that re-entry into the gaseous phase can happen only
when 2 atoms come together at the surface.
Even so, the statistics of random walk to the surface are far more
torturous than the statistics of pairing up and evolving as a molecule.
In the case of metallic atoms diffusing through the glassy matrix
of a stone tool, I would be very surprised if surface effects turned out
to be important in any way, but I would readily yield to any evidence to
I was a graduate student in 1950 working under an
assistantship in the Vacuum Tube Laboratory at Ohio State University.
My immediate supervisor was Prof. E. M. Boone who assigned me to
serve as run-fetch-and-carry for Dr. Oscar Heil.
Heil was a very colorful luminary in the vacuum electronics
firmament and, had Germany won WWII, he would have been credited with all
manner of inventions, including the klystron.
One day I called his attention to a faint glow in a small glass
vacuum tube… soon to become obsolete.
This brought forth an extended lecture on the permeability of glass
to Noble Gasses and assorted subjects, not necessarily related.
The earth’s atmosphere, I learned, was roughly 1% Argon… a
Noble Gas… the product of the radioactive decay of an isotope of
Potassium. If we assumed that
the Earth had no Argon in its atmosphere in the beginning, the time
required to accumulate the level we see today from the radioactive decay
of Potassium would be roughly 4 Billion Years.
This result was, by no means, universally accepted among top
scientists interested in such matters.
There were also traces of Helium, Neon, Xenon, and Radon… and
perhaps other Noble Gases… in the atmosphere due to similar radioactive
decay processes. Alert
observers in Germany had also noticed the same faint glow in operating
glass vacuum tubes and had studied the matter at great length a number of
years ago. The method
was simplicity itself. An
image of the glowing region was focused onto the input slit of an optical
monochromator… a spectrum analyzer… and the spectrum of the emitted
light was recorded. This
technique resulted in a wholly incontrovertible determination of the gas
species involved. These,
according to Heil, were all Noble Gases.
No Oxygen, no Nitrogen, no Hydrogen, none of the gases one would
expect to see if the vacuum envelope simply had a leak in it.
The only way these gases could get inside the vacuum was by
permeation directly through the glass.
Heil went on to tell me about a paper he had once
read of a formal investigation of the matter.
A commercial vacuum tube was not a convenient vehicle for this
study, so a thin wall glass enclosure was constructed with an electron gun
included so that the light of recombination of any ions formed within a
thin electron beam would be efficiently focused onto the slit of a
monochromator. The investigator could control the species and pressure
of the gas around the outside surface of the device.
I never saw this paper, in German, but according to Heil everything
that could be known regarding the permeation of Noble Gases through glass
In 1970 I was assigned to investigate the problem
of small klystrons being returned from our customers due to excess gas
levels. My studies completely
turned everything I had been told about Residual Gas on its head, as I
have written in the report on the following website:
My intuition tells me that newly broken surfaces
on flaked stone tools are sites of considerable stress at the atomic level
and extraordinarily active chemically as a consequence… at least until
those stresses are relieved by self-annealing or otherwise. Perhaps Noble
Gases from the atmosphere will be absorbed preferentially during this
period. Perhaps not. In any case it is well known that fully annealed glass will
absorb measurable quantities of Noble Gases from the atmosphere and that
these gases can find their way through a glass wall on the order of 1
millimeter thick, at room temperature, over a period of days, months, or
years. Anyone seriously
investigating the age of flaked stone tools through studying surface
phenomena would be well advised to consider this matter.
June 19, 2004