18 M E M I R ON THE 



above described, drove a musket-ball through seven white pine boards, of about 

 an inch inthickness. One hundred and ten grains of gunpowder caused the ball 

 to pass through eight boards of the same target. Two cylinders of gun-cotton of 

 the same size, that is to say, twenty-five grains in weight each, caused a musket 

 to burst. The iron of the musket, judging from its coarse crystalline texture, does 

 not appear to be of the best quality. 



These results seem to show, that while the force of gun-cotton, in guimery, is 

 to that of gunpowder as four to one, the ratio of the quantity of gas generated by 

 the former, to that generated by the latter, is as three to one 



The greater quickness of the deflagration of the gun-cotton may be the cause, 

 in part, of this diversity of ratio. Another cause may be, a more thorough com- 

 bustion. Of a large discharge of gunpowder, some portion escapes unburnt ; in 

 the case of gun-cotton, in the form employed in the experiments above mentioned, 

 none escapes. 



SUMMARY. 



It is an old and well accredited maxim in chemistry, to which there are but few 

 exceptions, that fluidity is requisite to chemical reaction. The fluid state, of which 

 the necessity is thus asserted, is with few exceptions attained only through water, 

 or heat, or both. In truth, however, when it is considered that without heat there 

 could be no fluidity, heat may be viewed as the sole solvent. As respects the 

 induction of the state requisite to chemical reaction, we may consider the solution 

 in which water is the ostensible agent, or igneous fusion in which it is absent, as 

 the only means of bringing the atoms of solids into the state requisite for chemi- 

 cal reaction, through which decompositions and recompositions are effected. 



It is well known that the affinities which prevail among the same set of bodies 

 when liquefied by aqueous solution, may be the opposite of those which they exert 

 when indebted to heat solely, for liquefaction. Thus there is scarcely any acid which 

 will not displace silicic or boric acid from alkaline bases when in aqueous solution, 

 yet when salts, consisting in part of the most energetic acids, are lused with silicic 

 or boric acid, decomposition ensues in consequence of the union of the acids last- 

 mentioned, with the bases ignited with them. 



The sulphates, carbonates, or hydrates of potash, soda, and of some other bases, 

 are per se indecomposable at any heat at which their bases cannot be volatilized ; 

 yet the nitrates of the same bases, are decomposed at the temperature of 

 incandescence. It follows that if a nitrate be exposed to igneous fusion 

 with any substance consisting more or less, of hydrogen, carbon, or sulphur, and 

 the oxygen of the nitrate will, by forming water with the hydrogen, carbonic acid 



