HUNTINGTON. — DIAMONDS IN METEORITES. 209 



not break up, and Figure 2 is an exact reproduction of a drawing of 

 one of these crystals, traced through a camera lucida attached to a 

 microscope. The original specimen measured only a little over a 

 hundredth of an inch in diameter, but viewed through a two-thirds 

 objective it showed distinctly the hexakis octahedral planes, the curved 

 edges, striatums, etc. exactly as seen in the drawing. Unfortunately, 

 the print cannot show the adamantine lustre and clear water of the 

 crystal. 



A portion of the powder was sent to Mr. Kunz for the diamond- 

 cutting experiment, but it was tried at first hastily and without success. 



The author, however, was so sure of the nature of the material that 

 he repeated the experiment in company with Mr. Kunz, on Monday, 



Fig. 2. 



September 11, 1893, in the Tiffany Pavilion of the Mining Building 

 of the World's Columbian Exhibition. A newly planed wheel had been 

 provided, through the courtesy of Messrs. Tiffany & Co., but in order 

 to make the experiment doubly sure a diamond set for cutting was 

 placed in position on the wheel, and left there for a period of five 

 minutes, while the wheel was making twenty-five hundred revolutions 

 per minute. On removing the diamond it was found that there had 

 been no appreciable shattering of the edges by friction, and that it 

 would take a long time for its own powder to be produced in sufficient 

 quantity to have any effect. 



The wheel was then charged with the residue from the Canon 

 Diablo iron, mixed with oil in the usual way. The diamond immedi- 

 ately gave out a sharp hissing sound, making it apparent at once to 

 an expert that the material was cutting, and in a few minutes it was 

 found that a face had been ground down and polished. Two other 

 vol. xxix. (n. s. xxi.) 14 



