64 HISTORY OF GALVANISM. 



the negative electricity. Although flame is a 

 conductor of galvanism, it does not conduct it so 

 perfectly as metals. No effect is produced when 

 flame is interposed between the extremities of 

 the pile. Flame is, however, a very different sub- 

 stance according to the body from which it is pro- 

 cured : the above observation refers to the flame 

 of a hydro-carbon on s body. The flame of sul- 

 phur insulates both the poles ; and that of phos- 

 phorus insulates the positive, and conducts the 

 negative influence. Phosphorus must therefore 

 be placed in the fifth class of bodies ; and perfectly 

 dry soap is also a negative conductor. 

 Soapane- The author gives an account of a number of 

 experiments that he performed on this latter sub- 

 stance, many of which are curious and original. 

 Hard soap, when perfectly dry, if applied to either 

 end of the galvanic pile, conducts all the electri- 

 city from that extremity into the ground, and 

 there appears to be no perceptible difference in its 

 action upon the two extremities. If wires be 

 connected with each end, and be made to ter- 

 minate in a prism of hard dry soap, which is 

 kept insulated, the circuit will not be completed ; 

 but if this soap be uninsulated, by establishing a 

 communication with the ground, an electrometer 

 connected with the positive pole manifests a great 

 degree of divergence, while one on the negative 

 pole loses all signs of it. " Consequently," M. 

 Erman observes, " the soap which insulates the 

 positive effect, is a perfect conductor for the ne- 



