Prof. Graham on the Law of the Diffusion of Gases. 35 1 



any other point is as the sine of the angle which the radius 

 drawn to that point makes with the above plane. 



If an electrized point influence an electrized sphere, the in- 

 fluence at any point is as a constant quantity minus another 

 quantity which varies inversely as the cube of the distance 

 from the influencing point. 



April 10, 1833. R. MURPHY. 







LVHI. On the Law of the Diffusion of Gases. By Thomas 

 Graham, Esq. M.A. F.R.S. Ed., Professor of Chemistry in 

 the Andersonian University, Glasgow. 



[Concluded from p. 276.] 



13. Carbonic Oxide. 

 SPECIFIC gravity, 0*9722, &c. as in the case of nitrogen. 

 •^ Gas prepared by the action of sulphuric acid on crystal- 

 lized oxalic acid, well washed with caustic ley. 



On 803 measures carbonic oxide and vapour, a contraction 

 of 11 measures in fifty hours, 12 measures in eighty-nine hours, 

 12 measures in ninety-seven hours; or 803 became 791. The 

 diffusion was slower than usual, from the plug having been 

 partially wetted in filling the instrument with gas. 



— — = 1*0149 = diffusion-volume of carbonic oxide, bv ex- 



803 J 



periment. 



1*0140 = diffusion- volume of carbonic oxide, by 

 theory. 



In the case of the last three gases, when the experiment was 

 performed over water in a diffusion- tube, with free exposure to 

 the dry atmosphere, instead of any contraction ensuing, a po- 

 sitive expansion generally occurred, which was to be attributed 

 to the return air, which was comparatively dry, being expanded 

 after entering the receiver. 



1 4. Carburetted Hydrogen of Marshes. — Specific gravity, 

 0*555. Diffusion-volume, 1*3414. 



In an experiment with this gas, deducting a small quantity 

 of air which it contained, 252 measures were replaced by 187 

 air. 



—— = 1*344 = diffusion-volume, by experiment. 



1*341 = diffusion-volume, by theory. 

 These are all the permanent gases which could conveniently 

 be submitted to diffusion. Vapours cannot be rigidly exa- 

 mined, as they are all condensible in the pores of the stucco. 

 The following Table exhibits a summary of the results : 



