MICA AND THE MICA MINES. 



661 



found in Siberia, "but these are exceptional. The average block 

 is little larger than the page of a magazine, and is generally less 

 than six inches in thickness. It separates very readily into sheets 

 parallel to the base of the prism. It is estimated that this cleav- 

 age may be carried so far that it would take three hundred 

 thousand of the mica plates to make an inch. It is needless to 

 say, however, that such a thickness is not suitable for service in 

 stoves and furnaces. The mica is generally split into plates vary- 

 ing from about one eighth to one sixty-fourth of an inch in thick- 

 ness. In preparing these plates for market, the first step is to 

 cut them into suitable sizes. Women are frequently employed in 

 this work, and do it as well as, if not better than the men. The 

 cutter sits on a special bench which is provided with a huge pair 

 of shears, one leg of which is firmly fixed to the bench itself, 

 while the movable leg is within convenient grasp. It is requisite 

 that the shears shall be sharp and true, for otherwise they will 

 tear the mica. 



The patterns according to which the mica is cut are arranged 

 in a case near at hand. They are made of tin, wood, or paste- 

 board, according to the preference of the establishment. Gener- 

 ally they are simple rectangles, varying in size from about four 

 square inches to eighty. The following table, taken from actual 

 use, will give some idea of the numerous sizes cut, and of the the- 

 oretical prices which correspond to them. The actual prices are 

 at present about forty per cent less : 



