ltJ26.) of t\e new Varieties of Carbon, i^ti '-' im 



This being premised, the next step in the inquiry is to ascer-* 

 tain what are the means, exclusive of crystallization, of reducing 

 a rarer to a denser form of matter. But two modes of doing 

 this are at present known ; viz. diminution of temperature ; and 

 the approximation of the molecules of bodies by mechanical 

 means, in which an evolution of caloric takes place. The pro- 

 duction of solid from aeriform matter by the combination of two 

 gaseous bodies, is not to be regarded as a third method of 

 effecting this ; for it is merely a case of the first mode just 

 mentioned ; the temperature at which the elements of the solid 

 which is formed are retained in the gaseous state, being insuffi- 

 cient to allow their combination to remain aeriform. The pro- 

 duction of solid carbonate of ammonia by the union of the 

 carbonic acid and ammoniacal gases, is a familiar illustration of 

 this process. 



Now, as already observed, there is every reason to believe, 

 that no definite distinction exists between the state of gas and 

 liquid, but that the only physical difference between the lightest 

 gas and the heaviest liquid, is in density ; the intermediate 

 degrees being supplied by vapours and liquids increasing ia 

 density in the most gradual manner. We know too that the 

 first result of the application of cold to a gas susceptible of 

 reduction to the liquid state, is its condensation ; we know that 

 this condensation goes on with the diminution of temperature, 

 until at length, when the process has been carried to a sufficient 

 extent, the result is the successive production of dense vapour 

 and of liquid. It affords no argument against what I am advanc- 

 ing, that the combined application of cold and pressure is in many 

 cases necessary to effect this ; for each successive stage in the 

 condensation is produced, with the one agent, by the abstraction 

 of caloric, and attended, with the other, by its evolution ; so 

 that the passage of latent into sensible heat takes place in the 

 same manner, and is as materially concerned in the process, as 

 would be the case, were either method to be employed exclu- 

 sively. 



With this train of consistent phfenomena before us, and with 



bodies ceases to conform to these rules, only in the moment of their transition from one 

 sta';e of aggregation to another." 



The reader, however, vrill not fail to perceive, that a circmidstance alluded to in the 

 last clause, is unfavourable to my opinion ; and as the statement is one of some import- 

 ance, and I am not quite satisfied of the accuracy of the foregoing translation, it may 

 be as well to subjoin the extract in the original German. 



" Die Compression tropfbar flilssiger Kiirper ist, so weit bis jetzt unsere Erfahrungen 

 reichen, demselben Gesetze unterworfen ; auch hier scheint Compression und Druck- 

 kraft im Verhaltniss zu stehen. Man kann daher annehmen, dass die zu tropfbaren 

 FlUssigkeiten uingewandelten Gase von Neuein anfangen dem niimlichen Gesetze z\x 

 folgen, welchem sie als Gase entsprachen. Auch ist es ziemlich wahrscheiiilich, dass 

 die in feste Korper umgewandelten FlUssigkeiten jenem Gesetze unterworfen sind. 

 Wenn sich diess durch weitere Versuche bestatigt, so kann ntian sagen, dass die Zusam- 

 menpressung eines Korpers nur allein in den Uebergangsmomenten aus einen Aggrega- 

 tions-Zustand in den andem aufhore Sich bach jenem Gesetze zu regeln." 



