TRANSACTIONS OF SECTION B. 503 



Section B.— CHEMICAL SCIENCE. 



President of the Section— Joseph Henry Gilbert, 

 Ph.D., F.R.S., F.C.S., F.L.S. 



[For Dr. Gilbert's Address see page 607.] 



THURSDAY, AUGUST 26. 

 The following Eeports and Papers were read : — 



1. Report of the Committee on the Best Means for the Development of Light 

 from Coal Qas of different qualities. Fart JI.— See Reports, p. 241. 



2. On some Uelations between the Atomic Volumes of Certain Elements and 



the Heats of Formation of some of their Compounds. By "Walter 

 Weldon, F.'B.S.E. 



3. On the Influence of Water on the Union of Carlonic Oxide ivith Oxygen 



at High Temperatures. By Haeoi-d B. Dixon, M.A., F.C.S. 



When a spark from a Leyden jar is passed through a mixture of two volumes 

 of carbonic oxide and one volume'of oxygen, which has heen thorouglily dried, no 

 explosion is caused. It is very difficult to dry the gases thoroughly enough to 

 prevent the explosion under atmospheric pressure ; but by a reduction of pressure 

 it is easy to show that a mixture of dry gases will not explode under the influ- 

 ence of the spark, which mixture readily explodes on addition of a minute trace of 

 moisture. It was found that, when the pressure in a dried eudiometer was gra- 

 dually increased until the passage of the sparlc caused the gases to combine, the 

 disc of flame passed quite slowly down the tube, whereas when the tube was satu- 

 rated with moisture the flame travelled too quickly to be followed by the eye. 

 Some of the mixture sealed up in a glass tube with anhydrous phosphoric acid 

 under atmospheric pressure, would not explode on passing a succession of sparks 

 through it. On opening the sealed end under water, the spark caused the gases to 

 unite. Into a similar tube containing anhydrous phosphoric acid, a piece of potash 

 was fused to the glass ; when filled with the mixture and sealed up, the gases 

 would not combine on passing the spark. On gently lieating the potash wfth a 

 Bun.sen flame, the spark caused an explosion. 



It was found that a small admixture of dry carbonic acid with the gases 

 had no effect in determining the explosion. Neither dry nitrogen nor dry cyanogen 

 had any effect, while the smallest admixture of hydrogen or ether vapour caused 

 the gases to explode on passing a spark. From these experiments it appears 

 probable that the oxidation of carbonic oxide is really caused by the alternate re- 

 duction and oxidation of water molecules, according to the equations: — 



(1) CO + up = CO., + II., 



(2) 2H,, + 0., = 2H.,0. 



A comparatively small number of water molecules suffices to determine the explo- 

 sion ; but the explosion gains in intensity the greater the nmnber of water molecules 

 present. It was shown by experiments at 52° C. that the force of the explosion was 



