l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 143 



men are suggestive of the mold from which the Keene, N. H., bottle 

 must have been made. 



An argument commonly used to support a natural rather than arti- 

 ficial origin for tektites is based on the relatively high temperatures 

 required to melt glass of tektitic composition. We have difficulty at- 

 taining these temperatures today; therefore, we are apt to conclude 

 unjustifiably that these temperatures must have been unattainable in 

 the fairly recent past. However, there is evidence that leads one to 

 doubt this reasoning. An example is given in the studies of Hubbard, 

 Jenkins, and Krumrine (1952), in which they compare the properties 

 of modern commercial glasses to Amelung glasses. These antique 

 glasses were made in the large factory of Johann Friedrich Amelung 

 near Frederick, Md., in the years around 1800. Hubbard et al. re- 

 port that these old glasses ". . . had working temperatures con- 

 siderably higher than any of the modern commercial glasses studied, 

 with the exception of fused silica and Vycor." They further noted 

 considerable difficulty in working these glasses after heating to 

 I500°C, the highest temperature to which they cared to take Globar 

 furnaces. 



Glass has been a common item in commerce along the east coast 

 of the United States since the early Colonial period, and it is a 

 byproduct of many industrial and manufacturing operations. There 

 is a possibility that starting with the proper raw materials — perhaps 

 by accident — glass of the composition of the Georgia and Martha's 

 Vineyard tektites could have been formed in this still difficultly at- 

 tainable high-temperature range. Had Precambrian feldspar or other 

 geologically old materials been included among the raw materials 

 from which this peculiar glass was made, another difficulty could pos- 

 sibly be reconciled. Conceivably the mysterious process that formed 

 the glass could have produced a product that retained sufficient radio- 

 genic argon-40 to give the approximately 30-million-year ages that 

 have been reported in the literature for the Empire, Ga., specimen 

 (Reynolds, i960; Gentner and Zahringer, i960). Admittedly, this 

 suggestion is contrary to normal laboratory experience ; however, this 

 type of measurement as applied to tektites is too new to be accepted 

 without reservations. 



Two criteria are commonly accepted in defining and identifying 

 tektites. The first is that the specimens are of natural occurrence 

 within a given although perhaps not completely delineated geographic 

 area; the second is that they are glasses of an unusual range of 

 chemical compositions, exhibiting characteristic physical properties. 



