KEW THEORY OF MIXED GASES. 267 



\Jt, All the gafes, whatever may be their denfity or the Condufions. 



Expan" 

 gafes. 



quantity of water they hold in folution, and all vapors, equally Ex P a "fionof 



dilate by the fame degrees of heat. 



2d, The augmentation of volume which each of the perma- Augmentation 

 nent gafes receives, from the temperature of melting ice to oi voIumc * 

 that of boiling water, is equal to y ^ *^ 3 of the primitive vo- 

 lume, if judged by the thermometer divided into 80 parts, and 

 i6-£,§7 °f tne f ame volume, if by the centigrade thermo- 

 meter. 



It remains, in order to complete this courfe of experiments, Future experi- 

 to determine the law of the dilatation of gafes and vapors, in me nts on the 



1 r • . ^ • ,-,•..,* , ,aws of dictation 



order to alcertam the coefficient or dilatation for any degree at at other tempe- 



a known heat, and to be affured of the real progrefs of the ra *ures. 



thermometer. I (hall employ myfelf on thefe new refearches; 



and when they are terminated, I (hall have the honour of 



communicating them to the Inftitute. 



VII. 



New Tlieory of the Conftitution of mixed Gafes elucidated. In a 

 Letter from Mr. J. Dalton. 



To Mr. NICHOLSON. 



SIR, Manchejler, Nov. 18, 1802. 



J.N a paper of mine which you had the goodnefs to publifli in New theory of 

 your Journal for 1801 (Quarto Series, V. 241), I announced the conftitution 

 a new theory of the conftitujtion of the atmofphere. This has fphere 

 fince been published on a more enlarged fcale, and elucidated 

 by a plate, &c. in the Memoirs of the Literary and Philofo- 

 phical Society of Manchefter, Vol. V. Part 2. Notwithftand- 

 ing this, I am informed by fome of my chemical friends, that 

 they do not clearly underftand the hypothefis itfelf, and confe- not clearly un- 

 quently are not able to judge of its merits or defects : And a derftood « 

 late writer (Dr. Thomfon), in his Syftem of Chemiftry, Vol. 

 III. Page 270, fpeaking of the uniform diftuiion of the differ- 

 ent gafes of the atmofphere, makes the following obfervation : 

 •' Even Mr. Dalton's ingenious fuppofition, that they neither 

 " attraft nor repel each other, would not account for this equal 

 " diftribution ; for, undoubtedly, on that fuppofition, they 



94 would 



