132 SOURCES OF HEAT AND COLD. 



intense chemical reaction, is a collateral, rather than a necessary con- 

 sequence of it. 



"As an example in which caloric is rendered sensible, by the 

 method in question, the inflammation of turpentine by a mixture of 

 nitric acid, with sulphuric acid, may be adduced." 



" The inflammation of alcohol, or oil of turpentine, by means of 

 a chlorate and sulphuric acid, as represented by this figure, affords 

 another exemplification perfectly in point." 



" About as much chlorate of potash as may be piled upon a half 

 c'ent, being deposited in a heap, in the inflammable liquid, and con- 

 centrated sulphuric acid being poured upon the heap, the liquid is in- 

 flamed." 



" As portions of the liquid are sometimes projected into the air, in 

 a state of inflammation, it is expedient, for the security of the opera- 

 tor, to have the glass, used to convey the acid, fastened to the end of 

 a rod." 



(df.) Electricity and Galvanism. The modes of excitement are 

 peculiar ; generally they are well known, but they belong either to a 

 different science, or to a different part of this science. 



The applications of the heat evolved in this way, are extremely 

 useful to the chemist ; the power is conveyed, conveniently, into and 

 through the interior of vessels, and thus gives us a furnace heat with- 

 out its inconveniences. The heat is mild or intense at pleasure ; no 

 heat, probably not even that of lightning, exceeds that produced by 

 electrical and galvanic arrangements. The decomposing powers con- 

 nected with common and galvanic electricity, produce the most curi- 

 ous and important results, dividing the material world between the 

 opposite poles, but this part of the subject is not appropriate to the 

 present topic. The facts and the instruments relating to Galvanism 

 are reserved for another place, except that I shall introduce here 

 from Dr. Hare, an instrument equally simple and useful. 



