On the Atomic Theory. 83 



ture and arrangement of solid and fluid substances which I have 

 now described ; even glass, although hard and very brittle, pos- 

 sesses a considerable degree of elasticity, and is consequently very 

 sonorous. 



The ultimate divisions of ponderable matter are exceedingly 

 minute; but those of the imponderable elements, such as caloric, 

 the electric fluid, and light, are so beyond calculation. The ut- 

 most stretch of the human mind can no more estimate the size 

 of those })articles, than it can measure infinite space or duration^ 

 However, their divisibility is limited, notwithstanding their 

 amazing minuteness. Probably a single ultimate particle of 

 caloric bears the same proportion, in its size and weight, to a 

 particle of oxygen, as the latter does to our globe : hence arises 

 the impossibility of ascertaining the weight of that element; — it 

 is likely that a still greater proportion, as to bulk and weight, 

 exists between light and caloric. 



From tlie foregoing considerations we can readily conceive the 

 nature and structure of the calorific atmospheres which are in- 

 fluenced by particles, atoms, and molecules of ponderable mat- 

 ter. 



The caloric which solid bodies contain may he partly set free by 

 •mechanical means : — instance ; — when the malleable metals are 

 quickly hammered or rolled between cylinders, their temperature 

 is considerably increased. This is occasioned by the closer ap- 

 proximation of their particles, which diminishes their capacity 

 for caloric. The temperature of gases is exalted by sudden com- 

 pression on the same principle. 



When certain solid bodies are made to act on each other che- 

 mically, more or less caloric and light are set free : — for example, 

 when sugar and oxymuriate of potash are pulverized and mixed, 

 a drop of sulphuric acid will produce a very rapid and vivid de- 

 flagration, which will pass througli the whole mass, be it ever so 

 large. When a spark is thrown into a mixture of nitre and 

 charcoal a similar effect is produced. Although the foregoing 

 facts are strong proofs of the existence of caloric and light united 

 to solid Ijodies, they are not to be compared with the following ; 

 viz. nitre three ounces and a half, crude antimony two ounces, 

 brimstone one ounce, all reduced to fine powder and well mixed, 

 will deflagrate rajjidly when a small spark is thrown in ; or the 

 ignition may be commenced by means of two or three grains of 

 oxymuriate of potash and sugar laid on the surface, and a drop 

 of sulphuric acid suffered to fall on it. During the decomposi- 

 tion intense heat aud dazzling light are set free. In this process 

 the nitrous acid of the nitre is decomposed, its oxygen lujites to 

 the antimony and sulpinu- ; the new compounds tRus formed de- 

 manding less caloric than the nitre, the surplus is set at liberty. 

 F 2 There 



