236 Proceedings of the British Association. 



tion of the first gas battery constructed with platina wire sealed into 

 glass tubes in pairs, — hydrogen being put into one tube, and oxygen 

 into the other. An arrangement of this kind being connected with a 

 voltameter, it was found that exactly the same quantity of gases was 

 eliminated in the tubes of that instrument as combined in the tubes of 

 the battery. Experiments have been made with a view of ascertaining 

 if other gases might be used in the battery, and it was discovered that 

 a great variety of gases might be so used. Prof. Grove then pointed 

 out how perfectly any eudiometric analyses might be carried on with 

 the gas battery, provided some attention were paid to a few sources 

 of error. A form of the instrument as hitherto constructed by Prof. 

 Grove was described, for the purpose of avoiding the absorption 

 of atmospheric air by the fluid in the cells of the battery. A more 

 recent construction of the battery was next described, in which 

 many of the imperfections of the former instruments were removed, 

 and a combination of several pairs of gas tubes are connected in one 

 compact body. Another advantage arising from this battery is the 

 really constant condition of it ; once charged it appears that the action 

 will go on for years, requiring nothing more than occasionally, at 

 long intervals, adding a little zinc to the acidulated solution in the 

 cells, for the purpose of supplying the loss of hydrogen in the tubes. 

 The results of long experiment have shown, that the most invariable 

 action may be calculated on for years ; and that, by this instrument, 

 experiments requiring for a long period the constant flow of a galvanic 

 current may be most effectually carried out. Some experiments on 

 the combination of phosphorus and sulphur with oxygen in the battery 

 were then named ; and it was found, that any body capable of volati- 

 lization gave a galvanic action with oxygen in the other tube. Cam- 

 phor, alcohol, ether, and other bodies proved the constancy of this 

 effect. It was then stated, that in all cases it had been found that 

 chemical action and voltaic action were convertible into each other. 



'On the Action of Gases on the Prismatic Spectrum,' by Dr. 

 Miller. — Referring, in the first instance, to the experiments of Sir 

 D. Brewster, on the changes produced on the fixed lines of the 

 prismatic spectrum by various absorptive media, Dr. Miller proceeded 

 to explain his method of examining the subject. The light, being 

 passed through a longitudinal slit in a plate of metal, was received 



