HEW OLEAGINOUS COMPOUNU, 337 



served in this state, through the medium of cither of the 

 above-mentioned solvents ; therefore the union of these two 

 bodies furnishes a very good illustration of the old chemical 

 law: — " Corpora non agunty nisisint soluta.^^ But, how- 

 ever, this axiom has now become obsolete, and rendered 

 totally inconsistent as to its general application, from our • 

 present and more refined laws of chemical affinity; yet^ 

 nevertheless, I think it may be considered in the present 

 combination as one fully applicable, because it illustrates 

 the formation of the compound. Indeed, I shall have whicli will not 

 occasion to show, by the following experiment, that, if the j^^ be in too 

 connecting medium or solvent of these two bodies be de- iarge propor- 

 stroyed by increasing the quantity of water, a subsequent 

 diminution of power of that medium as a solvent must inevit- 

 ably result; and the benzoic acid' will be precipitated in 

 crystals, while the camphor, the remaining constituent, will 

 rise to the surface of the fluid. 



Eooperiment 1. — Twenty grains of benzoic acid, and the FxpA. — Bf?n-» 

 same quantity of camphor, were mixed in half an ounce of^^J^^p^'^^^^'j'g, 

 alcohol, which readily dissolved them without the least solved in alco- 

 change; but immediately on the addition of the same Q^^^-add'ad **^*'^ 

 tity ©f water, the substance in question was produced, ac- 

 companied with a sensible evolution of caloric. This pro^^ 

 duction of heat, however, must be well known to depend 

 on the powerful attraction, which the alcohol and water 

 mutually exert to enter into chemical combination ; and 

 may be said to depend, according to Berthollet, on the 

 condensation of volume*. 



On allowing this solution to remain quiet, it gradually The fluid sepa,. 

 separated into two strata; the uppermost of which ^^s a^J^^^^ ^"^^ ^^° 

 spirituous solution of a pale yellow colour : and the lower 

 one was the new combination. 



The properties of the upper stratum are as follows : It-Froperties of 

 was of a pale yellow colour: (owing, no doubt, to aquan-^^'^"^^^^'^* 

 "tity of resin, which the acid contained, for if the acid bo 

 perfectly pure, both the oleaginous compound, and the so. 

 lution above it, are perfectly transparent.) It was acid, 

 and when exposed to a gentle heat in a retort, a spirituous 

 solution, containing a quantity of camphor, came over, 



* Berthollet, Chem. Stat. v. i. 

 Vol. X^J^VIII, Supplbment. ^ wMek 



