EXPLOSI VENESS OF NITRE. 19 



with the carbon, or sulphuric acid with the sulphur, cause the nitrate to be replaced 

 by a hydrate, a carbonate, or sulphate.* 



But as in every atom of nitrate, there are, independently of the base, five atoms 

 of oxygen, and since to convert hydrogen into water requires one atom, to convert 

 carbon into carbonic acid requires two atoms, and to effect an analogous change 

 in sulphur requires three atoms, it follows that for every atom of hydrogen there 

 will be four atoms of oxygen liberated, for every atom of carbon three atoms, and 

 for every atom of sulphur, two atoms. Each atom of oxygen is to the weight of 

 nitrate of potash as 8 to 102 ; hence there will be by hydrogen nearly 32 per cent., 

 by carbon nearly 24 per cent., by sulphur 16 per cent, of oxygen evolved to act 

 upon the excess of the contiguous combustible matter. Meanwhile it must be re- 

 collected that gum, sugar, starch, and lignin, (or fibre of wood, cotton, or linen) both 

 hydrogen and oxygen, exist in due proportion to generate water ; and besides 

 these compounds formed with oxygen, we have nitrogen to aid,t which is more in- 

 coercible than water or carbonic acid. Since at the heat produced by the com- 

 bustion of hydrogen or carbon, with pure oxygen, iron, the most tenacious of all 

 the materials at our command, is perfectly fusible, it is evident that by mechanism 

 we cannot restrain the expansive foi'ce of the gaseous products producible as 

 above represented. I believe, I may say, that water has never been confined under a 

 white heat. Yet the expansive force of liquid carbonic acid is at the freezing 

 point of water, thirty-six times as great as the pressure of this liquid at its boil- 

 ing point It has already been observed, that nitrogen, in expansive violence must 

 go beyond carbonic acid. It follows, that excepting the blow of a hammer, or the 

 force created by gravitation in falling bodies, we have no means by which we can 

 enable nitre, in the state of incandescent igneous fluidity, to come into close con- 

 tact, even for an i7istant, with masses of combustible matter, like those which it 

 was made to encounter in the store of Messrs. Crocker and Warren. 



It is to be presumed that it has been the want of this force which has caused 

 eflforts to produce explosions between nitre and combustibles, to fail ; and it is to 

 the presence of this force, where the fall of enormous masses of agglutinated 

 combustible matter upon incandescent liquified nitre, may be reiterated, that I 

 ascribe the destructive explosions, which, under such circumstances, have been so 

 prolific of impoverishment, mutilation, and death. 



* The powtji' of decomposing incandescent nitre by aqueous vapor, which was inferred by me to exis 

 in 1845, has since been fully vej-ided by the employment of this vapor by an American chemist, 

 Tilghman, to effect the decomposition of compounds containing potash, or other alkaline bases capable of 

 forming hydrates, per se, indecomposable by heat. (See Note, p. 10.) 



f Nitric acid consists of one atom of nitrogen as well as five of of oxygen. 



