VOLTAIC ACTION OF PHOSPHORUS, ETC. 297 



by the same means as described (42) ; they gave a very 

 decided deflection (the nitrogen representing zinc). This 

 deflection continues, the rise of liquid has been slow but 

 continuous, and the galvanometer feebly deflected. In the 

 turpentine experiment the rise is = 07 cubic inch, in the 

 cassia 0*5 ; the weights, however, from the irregularity of 

 absorption and evaporation, give no data as to the equivalent 

 consumption ; thus, the turpentine has lost 07 grain, the 

 cassia gained 0*05 grain. 



(48.) Alcohol and ether were tried in a similar manner, 

 and produced notable voltaic effects ; alcohol the most power- 

 ful probably, on account of its greater solubility in water. 



(49.) The rationale of the action in Experiments (43) and 

 (47) is curious. It seems that the platinum in the nitrogen 

 tube first decomposes the vapour of the hydrocarbons,* and 

 then the same platinum, with its associated plate, re-combines 

 the separated constituents with oxygen. In Experiment (43) 

 the decomposition takes place more quickly than the re-com- 

 position, as indeed would be expected from the absence of the 

 resistance of the electrolyte in the former case, and hence the 

 increase of gas in the nitrogen tube. 



(50.) The analogy of the action of the above volatile sub- 

 stances strengthens the position advanced (38), that solid 

 phosphorus should be regarded as volatile at ordinary tempe- 

 ratures, and sulphur when fused ; the whole of these experi- 

 ments also serve to introduce the galvanometer as a new and 

 delicate test, and in some cases a measurer of volatilisation. 



(51.) As the gas battery was shown in the former paper, 

 which I had the honour to communicate to the Society, to 

 give us the power of introducing gases which had been pre- 

 viously untried as voltaic excitants, and to ascertain their 

 electro-chemical relations, it has, by the means detailed in this 

 paper, opened a field for ascertaining the voltaic relations and 

 quantitative electro-chemical combinations of solid and liquid 

 substances, which from their physical characteristics had not 

 hitherto been recognised in lists of the voltaic relations of 



* I use this word here and in the title to avoid periphrasis ; it is not quite 

 correct as applied to some of these bodies. 



