Re: Large cities at time of contact Re: diseases and immunity
Philip Deitiker (pdeitik@bcm.tmc.edu)
Wed, 03 Jul 1996 15:50:04 GMT
Sisial@ix.netcom.com wrote:
>Philip Deitiker wrote:
>> Why do you say this (gee , do i really want to get in this argument).
>> The quality of the aztec glass knives was quite superb.
>I do not doubt the quality of the craftsmanship. That was not my point.
>Are you saying that an entire industry was built around the production of glass
>blades? Distinct from the production of flint and jade blades?
probably a subspecialization, from what I recall five or six
individuals where used to mine, select, and preprocess the pieces
before shipment for further processing by one or 2 individuals in the
metropolis.
>> As far as glass knives are concerned, they are still
>> being used in the feild of tissue preparation for electron microscopy
>> since they produce a much sharper edge and maintain the edge longer
>> than metal and I would consider them a 'high tech' thing, than high
>> tech production of knife is little different from what aztecs did.
>> So although they are less maliable than metal the quality of the edge
>> must also be taken into consideration. I might add the quality is no
>> different in manufactored glass than in natural glass once one begins
>> to chip the glass (except for tempered glass which can't reliable be
>> chipped).
I forgot to mention that glass edges are also used in analytical
balances.
>I do not see how you could possibly believe this. There is a big difference
>between manufactured glass and volcanic glass. For a start, manufactured glass is
>missing the impurities inherent in volcanic glass (ie obsidian is only 70% silica
>vs 72% just in common soda-lime glass, almost 100% in fused silica glass). The
>structure of manufactured glass is more uniform than that found in volcanic glass
>(due to the controled processes of manufacturing, ie even cooling. Because of
>uneven cooling, obsidain often contains quartz or feldspar crystals which weaken
>the structure of the glass).
The issue is that although most deposits are not going to be of good
quality (on average) if one is careful one can find pieces which are
highly silicate enriched and in some areas cooled properly. The rate
of cooling in natural pieces is going to depend on size and
surrounding insulation. Manufactored glass, from what I've seen is
cooled over about 12-24 hours, which is part of the range of cooling
in natural pieces. So I'de have to say if an industry was specialized
enough to know where to look and how to discern, say, from several
tons of deposit, which few pounds of pieces where most reliable and
learned how to make refined and useful impliments, kudoos to them.
>These are only the most obvious difference.
>The modern blades you mention are likely to be a form of fused silica glass. This
>is in no way comparable to volcanic glass. The edges of the blade are also likely
>to be laser cut.
Sorry, the glass blades for sectioning have been traditionally made
via encouraged fracturing (laser technology is out of the $ range for
most biological work) really not much different than the aztecs did.
Take just about any piece of glass irregardless of quality but
definable as glass and your going get a very sharp edge. Glass edges
differ from metal edges because metal polishing produces microscopic
ridges which incourage tearing as apposed to slicing. I could have
easily used a section of a new aztec knife for sectioning and get high
quality sections. Loan me one for a few years and I'de be happy to
give a demonstration (grin).
As far as the sectioning knives are concerned and how they compare
with the aztec knifes the desire is pretty much the same, what one
desires is to begin the fractoring process at the right angle to get
an edge within a small acute angular range. Too acute and the blade is
brittle, to steep and its cutting capacity is diminshed. For
sectioning its easy becasue only an inch or so is required, for the
aztecs a blade of a foot or so relatively strait and maintaining its
angle must have taken great skill to obtain.
>This produces a far more reliable blade than chipping. Basically,
>your Comparison of such fused silica blades to chipped volvanic glass is like
>comparing surgical steel to cold beaten chalcopyrite (no matter how expertly
>crafted).
Based upon what I've seen of the knives and what I've seen with the
sectioning knives the quality is comparable (FWIW), and may have been
a good reason for use in those sacrifices, the more fine the edge the
less tearing which is going to occur, and less pain.
>> BTW glass is not a stone, it is an amorphous homogenouous
>> solid with properties comparable to plastic at very low temperatures.
>This is about like comparing birds to ducks. Glass is a term which defines
>molecular structure. When it comes down to it, glass constitutes a supercooled
>liquid rather than a solid. Stone refers to any concreted earthy or mineral
>matter. Glass does qualify as a stone.
>But, this is beside the point. Volcanic glass was treated as any other stone. The
>processes used for the manufacture of glass tools was the same as the processes
>used for the manufacture of silicate tools.
You really beleive this? Esoterically yes, but functionally I think
one has to understand the behavior of glass in order to get a desired
result.
>> Of course it wasn't common, but it is representative of their quest
>> for more refined technologies. I think you might say it was a pinnacle
>> of their technologies, used principally by the top guys.
>While I have not seen any Aztec glass blades,
Then maybe you should, before you talk, they are quite impresive.
You'll see what I mean about sharpness.
> I have seen their work with jade and
>flint.
When glass fractures it gives much longer strait edges as apposed to
flint. flint may be preferable for short instruments, but glass is
preferable for longer instruments.
Philip
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