IO 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I43 



smaller than the smallest specimen were prepared for use in the sam- 

 ple and reference beam of the spectrophotometer. A blank correction 

 was determined by measuring the absorbance with the masks in posi- 

 tion previous to mounting the specimens. 



2.0- 



1.5- 



1.0- 



< 



0.5- 



Absorption Spectra 



■ Martha's Vineyard Tektite 

 Georgia Tektite 



1000 1500 



Wavelength in Millimicrons 



2500 



Fig. 2. — Absorption spectra of the Empire, Ga., and Martha's Vineyard, Mass., 



tektite specimen. 



The curves in figure 2 are essentially identical. The greater ab- 

 sorption of the Martha's Vineyard slice can be attributed to sample 

 thickness, suggesting that these two materials adhere to Lambert's 

 law and have the same extinction coefficient. 



SPECTROGRAPHIC AND CHEMICAL ANALYSES 



Semiquantitative spectrographic analyses of both tektites are shown 

 in table 3. Assuming that this type of analysis is within a factor of 

 only 2 of the correct value, one can say that the analyses of both speci- 



