50 FIRESIDE SCIENCE. 



which the coal is subjected. Heat is the great dis- 

 organizer which breaks up. or separates, the atoms 

 of carbon, hydrogen, nitrogen, sulphur, etc., and 

 forces them into new combinations. Most of these 

 substances are of a very remarkable character, and 

 largely employed in medicine and the arts. The 

 gaseous bodies are used for lighting, heating, bleach- 

 ing, etc. Ammonia is used for a great variety of 

 purposes, and is almost indispensable in some 

 processes or manufactures. Very nearly all the 

 ammonia consumed, amounting to many thousands 

 of pounds, is manufactured from the waste products 

 of gas-works, or indirectly from coal. Benzine, 

 benzoline, gasoleine, kerosolene, naphtha (all of 

 which may be included in the general term naph- 

 tha), are extremely light hydrocarbon liquids, of a 

 similar nature, but differing in density and volatil- 

 ity. Kerosolene, or rhigolene, is the lightest and 

 most volatile of all known liquids. It boils vio- 

 lently when exposed upon a warm day in summer. 

 Its specific gravity is 0.625. Benzine is employed 

 for making the beautiful aniline dyes, now so popu- 

 lar. The gorgeous rainbow tints derivable from 

 coal may be regarded as the stored-up sunshine of 

 a past geological epoch ; and the science and skill 

 of our advanced age have proved adequate for its 

 liberation or isolation. It is a curious fact that the 

 benzole obtained from petroleum cannot be con- 



