134 EULOGY OX ALEXANDER VOLTA. N 



stance, to the pile we are iu deb ted for the first decomposition of a great 

 number of alkalies and earths which were before considered as simple 

 substances; it is by it that all those bodies have become oxides; that 

 chemistry now possesses metals, such as potassium, which can be 

 kneaded by the fingers like wax, and will float on the surface of the water, 

 because lighter than it ; and are spontaneously kindled, diffusing the 

 brightest light. 



This would be the place to introduce all that is mysterious, I should 

 say almost incomprehensible, in the decompositions effected by the 

 voltaic pile ; to dwell upon the separate disengagements, completely 

 distinct, of the two disunited gaseous elements of a liquid, on the precipita- 

 tions of the constituentsolid principles of the same saline molecule, which 

 are affected by the particles of the fluid dissolving at great distances from 

 each other; on the strange, wild commotions that these different phe- 

 nomena s(^med to involve ; but time fails me. However, before finish- 

 ing this picture, I will remark that the pile is not merely a means of 

 analysis ; that if, by considerably changing the electrical affinities of 

 the elements of bodies, it often leads to their complete separation, its 

 power, delicately managed, has become, on the contrary, in the hands 

 of one of our fellow-members, the regenerative principle of a large num- 

 ber of combinations almost endless in nature and which art, up to this 

 time, knew not how to imitate. 



I will add a few more words still, to point out the different modifica- 

 tions undergone by the i>ile since passing from the hands of its illustri- 

 ous inventor. 



The characteristic feature of the pile consists of a large number of 

 pairs, or, binary combinations, of dissimilar metals. These metals are 

 usually copper and zinc; and these elements, the copper and zinc of 

 each pair, can be soldered together. 



The pairs follow in the same order. Thus when zinc is below in the 

 first, it is indispensably necessary it should be below in all the others. 

 Finally the pairs must be separated by a liquid conductor of electricity. 

 Now, who cannot see how easy it is to fulfill these conditions without 

 siqjerposing the elements, without forming them into a pile? This first 

 arrangement, which, by the way, was the origin of the name of the api^a- 

 ratus, has been changed. The pairs are not now vertical, but succeed 

 each other so as to form as a whole a horizontal parallelopiped. Each 

 of them is immersed in a trough containing a liquid, which is a decided 

 improvement over the merely moist pieces of pasteboard or cloth used 

 in the beginning. 



Apparatus have been constructed by several physicists under the 

 denomination of dry pile, which only comparatively maybe so called, as 

 strictly speaking they do not deserve the name. The best known, those 

 of Professor Zamboni, are composed of several thousands of disks of 

 paper, tinned on one side and covered on the other by a thin layer of 

 X^ulverized oxide of manganese, which is rendered adhesive by means 



