886.]! 



NEW YORK ACADEMY OF SCIENCES, 



273 



'J'hico ]);uiics in the United States have machinery, such as is 

 used in tlie crystal-cutting works of the Oberstein district, and 

 are jirepai'ed to manufacture jierfect spheres of rock-crystal, from 

 furnished material, at tlie following average prices: 1 inch dia- 

 meter, ^1; 2 inches diameter, S5 to $8; 3 inches diameter, $15 to 



Largest crystal ball in the United States, 

 (j^a inches in diameter. 



Russian vase of rock-crystal, 

 5 inches high. 



$25; 4 inches diameter, $40 to 675; 5 inches diameter, 8125 to 

 $150; G inches diameter, 6200 to 1300; 7 inches diameter, 8300 

 to 1400. 



A crystal sphere 6f inches in diameter would lose in recutting, 

 in order to remove a "bulb of concussion,^' one-fourth of an 



