120 COMPRESSIBILITY OF GASES. 



air, hydrogen, nitrogen, and carbon dioxide, is Boyle's 

 law exactly true. 



Second, That the deviations increase more rapidly 

 than the pressures increase. 



Third, That hydrogen is less compressible than the 

 law demands. 



Fourth,' That other gases are more compressible than 

 they would be if the law were general ; and, 



Fifth, That both carbon dioxide and air vary less at a 

 higher temperature — the former conforming to the law 

 almost exactly at 100° C. 



But even these trustworthy experiments were not des- 

 tined to long remain the last effort in this direction. It 

 afterwards apjjeared that they did not reveal the whole 

 truth. In fact, true as Regnault's results might be 

 within the limits of pressure which he employed, the 

 most natural inferences projected beyond those limits 

 could not be verified. The pressures employed ran up 

 to about thirty atmospheres. Air and other gases, ex- 

 cept hydrogen, became more and more compressible as 

 this limit was approached, — why should they not con- 

 tinue to do so when this limit was surpassed % Such 

 was generally conceded to be the fact. 



NATTERER 1 — 1850. 



But this inference was contradicted by the investiga- 

 tions of batterer, who in 1850 experimented with gases 

 under pressures enormously greater than had ever be- 

 fore been reached. By a powerful forcing pump nearly 

 three thousand atmospheres were brought into action. 

 Hydrogen, oxygen, nitrogen, air and nitrous oxide were 

 submitted to these tremendous pressures. Hydrogen 

 alone maintained its behavior the same as when treated 



1 Cooke in Chemical Physics, p. 299, gives a table of Natterer's results taken from 

 Leibig and Kopp, Jahresbericht Pur 1851, seite 88, to which he refers. For full results 

 the same author refers to Wien Acad. Ber. xii, 199. or Pogg. Ann. xciv, 436. 



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