and of charcoal 

 with no metal. 



Volta's account 

 of his own the- 

 ory. 



Dr. Van Marum 

 charges a large 

 battety by gal- 

 vanifm. 



Dr. Prieftley's 

 experiments. 



Galvanifm faid 

 not to a& on 

 water under oij j 



rflSTORY O* GALVANISM. 



which contains no metal, and which confifts folely Of pieces of 

 charcoal, which have their different fides expofed to the a&ion 

 of different fluids. 



In the fame volume there is an account of a paper written 

 by Volta himfelf ; but from the opinions which are advanced 

 in it, we may conclude that he was unacquainted with many 

 of the moll interefting circum (lances which had been obferved 

 in this country, refpe&ing the operations of the apparatus ori- 

 ginally difcovered by hknfelf. 



In the 40th volume of the Annales de Chimie, is a letter 

 from Dr. Van Marum to Sig. Volta, containing an account of 

 experiments performed in order to compare the effects of the 

 galvanic pile with thofe of the great Teylerian machine at 

 Haarlem. Both (Ingle jars and batteries were charged by 

 means of the galvanic pile, and in all cafes they were charged 

 to the fame degree of intent] ty with that which the pile itfelf 

 indicated to an electrometer. When the zinc was at the top 

 of the pile, and communicated with the intide of the jar, the 

 electricity of the infide was found to be pofitive, and when the 

 pile was reverfed, it was negative. It was found that the 

 fhocks given by the battery charged from the electrical ma- 

 chine, were not perceptibly different from thofe given by the 

 battery when charged to an equal intenfity by the pile. By 

 conftru&ing a pile of large plates of zinc and copper, he was 

 enabled to fufe thick iron wires ; he even fucceeded in fufing 

 a wire of platina. He found that piles which confift of the 

 fame number of plates, but of different diameters, give equal 

 intenfities and equal (hocks; yet thofe with the larger plates 

 he found to be confiderably more powerful in fufing metals. 



In the firft volume of Nicholfon's Journal, N. S. is a letter 

 from Dr. Prieftley on the pile of Volta. It contains a number 

 of interefting experiments performed by this venerable philo- 

 fopher, principally with a view of eftablifhing his favourite hy- 

 pothefis of phlogifton, to which he (till adheres. Some of the 

 fads which he notices had been previoufly obferved in Engr 

 land, though from his remote (ituation he had not the opportu- 

 nity of becoming acquainted with them. He interpofed four 

 glafles of water between the two ends of the pile ; the glafles 

 were connected by means of filver wires, and the ufual opera- 

 tions went on at the legs of the wires; but it was found that 

 when one of the portions of water had its furface covered with 



oil, 



