VOL. LXVIII.] PHILOSOPHICAL TRANSACTIONS. 465 



a description of this new instrument, which I had received from his royal high- 

 ness the archduke Ferdinand, a very little while after Mr. Volta liad invented it. 



It is true, that Father Beccaria had a long while ago excited an electricity, 

 almost perpetual, by 2 panes of glass, one placed on the other, each having 

 but one metal coating, and joined together so that no metal was placed between 

 the 2 glasses. These 2 glasses being applied to a prime conductor of an elec- 

 trical machine, so as to receive a charge in the same way as one glass coated on 

 both sides is to be charged, afford numberless sparks from both coatings, after 

 the 2 glasses have been discharged in the common way, by making a communi- 

 cation between the 2 coatings. 



In order to produce these sparks, the 2 glasses must be separated from each 

 other, so as to avoid touching the coatings in the moment of separation. Each 

 of the coatings will give a spark, which may be repeated after having replaced the 

 1 glasses one on the other. After the 2 glasses have been thus joined again, 

 and touched after their conjunction, another spark is obtained from both after 

 their separation ; and these sparks may be thus repeated almost ad infinitum ; so 

 that these 2 glasses, once excited, seem to be an unexhausted source of elec- 

 trical sparks. Father Beccaria calls this experiment electricitas vindex. Whe- 

 ther this denomination be a proper one to convey some idea of what is under- 

 stood by it, I will not now endeavour to determine. The same father Beccaria 

 had also found, that the coating of a glass, alter being discharged, was able to 

 give new signs of electricity, when taken oft" by means of silk strings. Some 

 other experiments were made, many years ago, by Mr. Cigna of Turin, and 

 by some other electricians, which have a great deal of similarity with the 

 electrophore. 



But as the inventors of these experiments did not adapt them as an electrical 

 machine, they do not diminish at all, in my opinion, the honour which Mr. 

 Volta deserves, for having enriched the electrical apparatus with a very simple 

 and handy machine, continually ready to excite as strong an electricity as is re- 

 quisite for the more ordinary purposes. The novelty and simplicity of the 

 machine could not but strike every electrician ; I cannot express how much I 

 was pleased with the first sight of it, and with what eagerness I set about endea- 

 vouring to understand the nature of it. I analyzed it in various ways : I com- 

 pared it with Father Beccaria's electricitas vindex, with an ordinary coated glass, 

 and coated resinous electrics. 



Some electricians, puzzled with the strange phenomena which it affords, 

 thought it over-turned entirely the almost universally received theory of Dr. 

 Franklin, and that it could not be understood but by establishing new principles. 



After considering the matter maturely, I thought that these phenomena, 



VOL. XIV. 3 O 



