MICA 363 



the present time the Nevada deposits are too isolated to war- 

 rant mining on an extensive scale. The completion, however, 

 of the railroad, which is being constructed from California 

 across Nevada and Arizona to Utah, will make these deposits 

 more available for commercial purposes. 



The uses of mica arc somewhat varied ; there are two forms 

 in which it is used, (1) sheet or plate mica and (2) scrap mica. 



Mica is cut into sheets of various sizes which are used for 

 stoves, lamp chimneys, incandescent lights, and in electrical 

 apparatus for insulation purposes. While the use of this 

 sheet mica for stoves has decreased very rapidly during the 

 past ten years, there has been a corresponding increase in its 

 use for electrical apparatus. It is also used in place of glass in 

 the manufacture of a great many novelties and in many re- 

 spects increases the usefulness of the articles made. There 

 was formerly a considerable demand for the larger sheets of 

 mica, but these have been replaced to some extent at the 

 present time by a manufactured product known as micanite, 

 which is made from very small, perfect pieces of mica rearrang- 

 ed and cemented together into larger sheets. For some pur- 

 poses these manufactured sheets are as satisfactory as the 

 natural ones and are, of course, much cheaper. 



The value of sheet or plate mica varies with the size of the 

 sheet and is from 2 cents to $3 per pomid. The values of from 

 2 to 5 cents per pound are for the small disks and rectangular 

 sheets that are cut by machinery and are used extensively in 

 electrical apparatus. The larger sheets are cut by hand and 

 considerable skill is required to cut the largest pattern possible 

 from the crude block of mica. 



The waste or scrap mica not suitable for cutting into 

 sheets of even the smallest size has a value when ground to a 

 flour, w^hich is used in the manufacture of wall papers, lubri- 

 cants, fireproofing material, artificial snow^, novelties, etc. 

 Coverings for boiler tubes and steam pipes are also manufac- 

 tured from particles of scrap mica which are not ground but 

 are broken into pieces of approximately the same general 

 dimensions, one half by one fourth of an inch. These are then 

 arranged w^ith their longer dimension and face parallel to the 

 length of a wire net coil, pressed into the shape of a pipe or tube, 



