74 The Theory of Exphjions, 



The moft fimple principles of natural knowledge teach na 

 tliat atmofpheric air cannot pafs from its permanently aeri- 

 form ftatc to that of fluid or folid, by any degree of cold with 

 which we are acquainted. Admitting this to be true, there 

 is no longer any ground of furprife in feeing the burfting of 

 hodies which refift the force of freezing water. The air, a 

 fluid of permanent clafticitv, being compreflVd, and forced 

 to give way to the particles of water, which cold, or the at- 

 traclive pouqr of the atoms of bodies, draws violently toge- 

 ther, it follows that the ice, into which the water is con- 

 verted, muft break alunder, in order to afford a palTage to 

 this aerifomi fubftancCj which cold can neither condenfe nor 

 jnake folid, and rrtuft rend and fliiver, with a cracking noife, 

 the veflTels no longer able to hold it. 



This theory is rendered probable, and (Irengthened, by a 

 facl which I have obferved myfelf, viz. that the fats, fuch as 

 hog's fat, 8cc. fettle confiderably down in the veflels in which 

 they are condenfed. I have alfo noticed cavities in the in- 

 terior parts of fuch mafles of fat. Now, this (hrinking of vo-. 

 lumc, and thefc cavities in fat, undoubtedly, can only arife 

 from the extrication of atmofpheric air iji the proccfs of con- 

 denfation. Independently of this faft, which every body is 

 ready to atteft, there is not a Canadian peafant who is igno- 

 rant that the cavities found in a niafs of ice were formed by 

 air, and contain it. Thefefacls, therefore, prove that, in the 

 c<>n2;eIation of water, the atmofpheric air which exifts in the 

 inteHViees of the particles of water is forced to detach, or fet 

 itfelf at liberty, as foon as cold converts them into ice. 



On this principle it is eafy to explain the rending and 

 fplitting of trees, with a cracking noile, during the frofts of 

 winter; the burjlling of Hones in the moment of the conver- 

 fion of the water contained in them into ice ; and the break- 

 inc, as well as the lofs of the primitive perpendicularity of 

 V alls which had been built during the autumnal feafon. 



According to the Academy Del Chnento, it appears to be 

 demonlh-ativcly true, that frozen water occupies more bulk 

 than fluid water. This opinion fcems to clafli with all facl 

 and analogy : for we confider it as afcertained, that the fpe- 

 ciiic gravity of ice is greater than that of water; that is to fay, 



' "^ ^ tha^ 



