Hare'^s JVew Galvanic Jlpparatus, Theory, fyc. 107 



stantly fused at the end on being brought in contact with 

 some mercury communicating with the other. When two 

 cylinders of charcoal having hemispherical terminations 

 were fitted into the brass cylinders and brought nearly into 

 contact, a most vivid ignition took place, and continued 

 after they were removed about a half or three quarters of 

 an inch apart, the interval rivalling the sun in brilliancy. 

 The igneous fluid appeared to proceed from the positive 

 side. The charcoal in the cylinder soldered to the latter 

 would be intensely ignited throughout when the piece con- 

 nected with the negative pole was ignited more towards 

 the extremity approaching the positive. The most intense 

 action seems to arise from placing a platina wire of about 

 the eighth of an inch diameter, in connexion with the posi- 

 tive pole, and bringing it in contact with, and afterwards- 

 removing it a small distance apart from a piece of charcoal 

 (fresh from the fire) affixed to the other pole. 



As points are pre-eminently capable of carrying off (with- 

 out being injured) a current of the electrical fluid, and very 

 ill qualified to conduct caloric ; while by facilitating radia- 

 tion, charcoal favours the separation of caloric from the 

 electricity which does not radiate ; this result seems consist- 

 ent with my hypothesis, that the fluid as extricated by Vol- 

 ta's pile is a compound of caloric and electricity;* but not 



* According (o the theory here alluded to, the galvanic fluid owes its 

 properties to caloric and electricity; the former predominating in propor- 

 tion lo tlie siz.e of the pairs, the latter in proportion to the number, being in 

 both cases excited by a powerful acid. Hence in batteries which combine 

 both qualifications sufficiently, as in all those intervening between Chil- 

 dren's large pairs of two feet eight inches by six feet, and the 2000 four- 

 inch pairs of the Royal Institution, Ihe phenomena indicate the presence of 

 both fluids. In De Luc's column, where the size of the pairs is insignifi- 

 cant, and the energy of interposed agents feeble, we see electricity evolved 

 without any appreciable quantity of caloric. In the calorimolor where 

 we iiave size only, the number being the lowest possible, we are scarcely 

 able to detect the presence of electricity. 



When the fluid conlains enough electricity to give a projectile power ad- 

 equate to pass through a small space in the air, or through charcoal, which 

 impedes or arrests the caloric, and favours its propensity to radiate, this 

 principle heat is evolved. This accounts for the evolution of intense heat 

 under those circumstances, which rarify the air, so that the length of the jet 

 from one pole to the other may be extended after its commencement. 

 Hence the portions of the circuit nearest to the intervening charcoal, or 

 heated space, are alone injured ; and even non-conducting bodies, as 

 quartz, introduced into it are fused, and hence a very large wire may be 

 melted by the fluid, received through a small wire imperceptibly affected. 



See Silliman's Journal, No. 6, Vol. I. Thomson's Annal?, Pept, 1S1<?. 

 Tslloch's Philosophical Magazine. October. 1S19. 



