imprd^ed SUdi7ig'Rod Eudiometer and of the Volumescope. 175 



is perfectly consistent with the theory of volumes, and much 

 more consonant with my experiments, than that recommended 

 by the celebrated author of that admirable theory. 



The late Professor Dana ingeniously reconciled Gay-Lus- 

 sac's statement, with the theory of volumes, by suggesting that 

 one half-volume of oxygen may take one volume of the nitric 

 oxide, and another half-volume of oxygen two volumes. 



\ vol. oxygen takes 1 vol. oxide, and forms nitrous acid. 



\ ■ 2 — oxide,and forms hypo-nitrous acid. 



■ Deficit due to oxygen gas 



as 1 to 3. This result is evidently dependent 



upon the contingencies which may prevent nitrous acid from 

 being the predominant product. I have accordingly found it 

 precarious in at least 100 experiments, accurately made with 

 the sliding-rod eudiometer, of which an engraving and de- 

 scription will be found in the Philosophical Magazine, vol. Ixvii. 

 page 29 *. 



Application of the Volumescope to the Analysis of Carbonic 

 Oxide, or to that of Olefiant Gas, so as to show that the Re- 

 sidt corifirms the Theory of Volumes. 



Carbonic oxide requiring for its saturation half its bulk of 

 oxygen ; in order to analyse it in the apparatus last described, 

 after the preliminary preparations mentioned as necessary, in 

 case of the gaseous elements of water, introduce two volumes 

 of carbonic oxide, and one of oxygen gas, and ignite the pla- 

 tina wire. A feeble explosion will take place, and one volume 

 will disappear. To complete the analysis, by means of a fun- 

 nel screwed on to the cock inserted into the perforation in the 

 mahogany block at the top of the eudiometer, lime-water may 

 be introduced, and thus all the carbonic acid, generated by 



• 1 will here mention the mode of operating with that instrument which 

 I find preferable. The receiver being filled with water and immersed in 

 the pneumatic cistern, the apex A being just even with the surface of the 

 water, by drawing out the rod of the eudiometer, take into the tube 100 

 measures of atmospheric air and transfer them to the receiver. Next take 50 

 measures of nitric oxide from a bell as above described, and add them to the 

 air in the receiver, without allowing the gas to have any contact with the 

 water, which is not inevitable. Wash the mixture with a jet of water, which 

 is easily produced from the apex of the instrument, and draw the whole of 

 the residual gas into the tube, continuing to draw out the rod till 150 gra- 

 duations appear. In the next place eject the residual gas from the instru- 

 ment; the number of graduations of the rod which remain on the outside 

 of the tube shows the deficit i)roduccd by the absorption of the oxygen 

 and nitric oxide in the state of nitrous acid. If of this deficit, oncthird 

 be ascribed to the atmos{)heric oxygen, the result will agree very nearly 

 with those obtained by exploding ^atmospheric air and hydrogen, in the 

 f amo proportion, in tiie uliding-rou eudiometer, 



the 



