332 Dr, Harems new Galvanic Apparatus y Theory, ^c. [May, 



which supposes it to be electricity alone. The finest needle is 

 competent to discharge the product of the most powerful machines 

 without detriment, if received gradually as generated by them. 

 Platina points, as small as those which were melted like wax in 

 my experiments, are used as tips to lightening rods without 

 injury, unless in sudden discharges produced under pecuHar 

 circumstances.* 



The following experiment I conceive to be very unfavourable 

 to the idea that galvanic ignition arises from a current of elec- 

 tricity. 



A cylinder of lead, of about a quarter of an inch diameter, and 

 about two inches long, was reduced to the thickness of a com- 

 mon brass pin for about three-quarters of an inch. When one 

 end was connected with one pole of the apparatus, the other 

 remained ' suspended by this filament ; yet it was instanta- 

 neously fused by contact with the other pole. As all the calo- 

 rific fluid which acted upon the suspended knob must have 

 passed through the filament by which it hung, the fusion could 

 not have resulted from a pure electrical current, which would 

 have dispersed the filament ere a mass 50 times larger had been 

 perceptibly affected. According to my theory, caloric is not 

 separated from the electricity until circumstances very much 

 favour a disunion, as on the passage of the compound fluid 

 through charcoal, the air, or a vacuum. In operating with the 

 deflagrator, I have found a brass knob of about five-tenths of 

 an inch in diameter, to burn on the superficies only ; where 

 alone, according to my view, caloric is separated so as to act on 

 the mass. Having, as mentioned in the memoir on my theory of 

 galvanism, found that four galvanic surfaces acted well in one 

 recipient, I was tempted, by means of the 80 coils, to extend 

 that construction. It occurred to me that attempts of this kind 

 had failed i'rom using only one copper for each zinc plate. The 

 zinc had always been permitted to react towards the negative as 

 well as the positive pole. My coils being surrounded by copper, 

 it seemed probable, that if electro-caloric were, as I had sug- 

 gested, carried forward by circulation arising from galvanic pola- 

 rity, this might act within the interior of the coils, yet not be 

 exerted between one coil and another. 



I had accordingly a trough constructed with a partition along 

 the middle, so as to receive 40 coils on one side, and a like num- 

 ber on the other. This apparatus, when in operation, excited a 

 sensation scarcely tolerable in the backs of the hands. Inter- 

 posed charcoal was not ignited as easily as before, but a most 

 intense ignition took place on bringing a metallic point connected 

 with one pole of the series into contact with a piece of charcoal 

 fastened to the other. It did not take place, however, so spee- 

 dily as when glasses were used ; but soon after the ignition was 

 effected, it became even more powerful than before. A cylinder 



• See Adams's Electricity, on Points. 



