304 THE AMERICAN MONTHLY [Sept. 



moji ground glass, some of the "Carbon dust" to be 

 secured direct from any trimmers of globe arc lights in 

 any town where the arc system is used. The minerals to 

 be studied are surfaced down on the emery slab, with the 

 aid of water and the "Carbon dust," the coarse scratches 

 to be removed by gentle rubbing on the same slab, and 

 the polish to be given by transferring a little of the pasty 

 liquid from the emery slab, to the ground surface of the 

 piece of glass; the specimen must then be rubbed with a 

 circular or straight motion until the polish comes iii? on 

 the specimen, which takes but a few moments to do. 



Auotlier way to give the finishing polish, is to proceed 

 as follows: secure a piece of window glass eight inches 

 by ten and pour a considerable quantity of the carbon 

 dust on the glass. Spread the same all over the glass; 

 next let all of the powder slide off of the glass, and tap 

 the glass to detach all that will fall off, it will then be 

 observed that there remains an exceedingly fine layer of 

 the dust on the glass, which dust must be brushed to- 

 gether by a small roll of cloth; this dust when deposited 

 on a piece of ground grass or a thin piece of smooth 

 sheet iron, is moistened with a drop of water and the 

 mineral to receive the polish is rubbed with circular or 

 straight motions until a sufficient polish is attained, 



A point is usually reached in polishing where a sort of 

 suction contact is noted, and the moisture disappears, 

 when the polishing force is acting best. Should the polish- 

 ing film become dry while polishing, breathe once or 

 twice on the dry film and the polishing force is revived, 

 as a very little moisture seems to be necessary all the time. 

 Any person who will make the simplest effort to follow 

 the above instructions will have success after an hour's 

 trial and will then have a key to an indefinite amount 

 of intellectual and scientific pleasure awaiting him in the 

 field of Micro-Mineralogy. 



