IQC) CONSTITUTION OF MIXED GASES. 



another in fpirit of turpentine, which will enable you to falisfy 

 yourfelf and your readers whether thefe folutions deferve to he 

 placed in the clq/i qf varnijhes, and remain 



Your raoft obliged fervant, 



T. SHELDRAKE. 



No. 5, Montague-Street, - 

 * Rujfel-Square, 



IV. 



Reply to Mr, Dalton, on the Confiitution of Mixed Gafes^ 

 By Mr, JoHii GovGH» 



CJiarafter of 

 Mr. Dalton*s 

 reply. 



Mr. D.'t de- 



monftration rc- 

 Tiewed. 



To Mr. NICHOLSON. 



SIR, MiddleJkiWy Oa. 16, 1804. 



1 DID not attack Mr. Dalton's opinions openly, until he had 

 invited roe to do it ; the attempt has been made on my part 

 purfuant to his requefl: ; and he has replied, but in a manner 

 which feems better calculated to amufe the fuperficial reader, 

 than to convince the reafoner : For he treats the fubjecl, 

 fometimes with acrimony, and fometimes with ridicule ; in 

 the mean time his arguments are but few, and thefe appear to 

 be negligently condu6led. A bare infpedion of his own letter 

 will fupport the two firft charges, and I will now enter upon 

 the defence of the third. 



Mr. Dalton begins by pronouncing the diftin^ions which I 

 make betwixt a mechanical hypothefis and theory, to be nu- 

 gatory ; notwithfianding the caufes of thefe diriin6iions arc 

 fully llated in my Stridures. Now controverfy is of a nature 

 which always obliges a man to point out the fallacy or futility 

 of his opponent, when he can do it with fuccefs ; but this has 

 been negleded by Mr. D. in relation to my diftindlions, and I 

 leave him to draw the inference which refults from thefe ob- 

 fervations, 



Mr. D. proceeds, in the next place, to demonftrate the fun- 

 damental propofition of his hypothefis ; namely, the mutual 

 penetrability of gafes which do not attract nor repel each other. 

 For this purpofe he remarks, that oxigen repels oxigen, but 



not 



