so Mechanical Philosophy. 



sion of the Galvanic principle was connected with 

 new discoveries and improvements, from various 

 quarters; these, however, for a considerable time, 

 were generally small and unimportant in their 

 nature. 



But among all the recent discoveries in Galvan- 

 ism, that made by Professor Volt a, in 1800, is 

 most rem.arkable in its nature, and most interest- 

 ing in its relations. His mode of constructing a 

 pile, for condensing, retaining, and communi- 

 cating a perpetual current of the Galvanic influence ^ 

 is generally known.'" The curious phenomena 

 which this pile exhibits; the connection which 

 these phenomena indicate with the principles both 

 of electricity and of chemistry; and the numerous 

 experiments and successive improvements in the 

 management of this Galvanic battery suggested by 

 Professor VoLTA ; by Messrs. Carlisle, Nichol- 

 son, Cruickshank, Davy, and others, of Great- 

 Britain; by Van Marum, of Holland; and by 



JB The pile of Volt a is thus formed. Take a number of plates ol silver, 

 an equal number of zinc, and the same number ,of pieces of card or ivoollen 

 cloth. Let these last be well soaked in ivater, or water saturated with com- 

 mon salt, or what is perhaps still better, with nitre. A file is then to be 

 formed of these substances, in the following manner. A piece of zinc, a 

 piece of silver, and a piece of wet cloth or card, are to be successively 

 placed on each other; then another piece of zinc, and so on in the order of 

 the first layer. In this manner, the pieces are to be arranged, or in any 

 other manner, provided a regular alternation be observed, until the requi- 

 site number shall be laid. The instrument is then fit for use. The 

 pieces of card should be somewhat less than the pieces of metal, and after 

 being well moistened, should be gently squeezed before they are applied, 

 that the superfluous moisture may not run down the pile, or insinuate 

 itself between the pieces of metal. 



The instrument constructed in this manner affords a perpetual current of 

 the Galvanic influence; and if one hand be applied to the lowest plate, and 

 another to the upper, a shock is felt, as often as the contact is repeated. 

 The shock received from this pile is somewhat like that given by a Leyden 

 phial; but more nearly resembles that given by a Torpedo, which animal 

 this apparatus also resembles in giving incessant shocks. The intensity of 

 the charge is, however, too small to make its way through the dry skin ; it 

 is therefore necessary that each hand should be well wetted, and a piece of 

 metal be grasped in each to make the touch; — and the larger the piece of 

 metal which is thus held In the hand, the stronger the shock. Garnett's 

 Annah of Fhilou vol. i. p. 10, (5tC. 



