DIAMONDS AND DIAMOND CUTTING. 199 



American machinery is seen to be superior to the 

 Dutch. This we have already described. The 

 gem is adjusted in soft lead heaped conically in a 

 copper cup, ten times the capacity of those used 

 upon the cement sticks in cutting. The surface of 

 the wheel is charged with diamond dust mixed with 

 oil to the consistency of thin paste. The stone and 

 wheel thus arranged, the latter is made to revolve 

 at the rate of fifteen hundred revolutions a minute, 

 and the stone, placed in a heavy iron clamp, is in- 

 verted upon the wheel. Nothing but the diamond 

 touches the wheel, it being pressed down by the 

 weight of the iron clamp. A rather musical tone is 

 produced by the contact, which shows that the 

 wheel is doing its work, and that now a bright sur- 

 face will be produced upon the " table " exposed to 

 its action. When this is satisfactory, the operator 

 melts the lead, releases the gem, and readjusts it so 

 as to polish another of the faces, and in this way the 

 process goes on until the work is completed. To 

 attain this, however, the tables and faces are many 

 times exposed to the wheel, and it is not until the 

 most careful measurements and experiments are 

 made that the gem is pronounced satisfactory. Mr. 

 Morse has been intrusted with the manipulation of 

 some of the most costly diamonds ever brought to 

 this country, and in no instance have his labors re- 

 sulted in loss or failure, a circumstance which re- 

 flects much credit upon his ingenuity and skill. 



