Chemical Science. 169 



9. Prize Question ; Natural Philosophy. — 1. " ( To determine by 

 numerous experiments the density acquired by liquids, and espe- 

 cially mercury, water, alcohol, and sulphuric ether, by pres- 

 sures equivalent to the weight of many atmospheres. — 2. To 

 measure the effects of heat produced by these compressions." 

 The prize a gold medal of three thousand francs value. Memoires 

 received tillJan. 1, 182G. Royal Academy of Sciences, Paris. 



II. Chemical Science. 



1. On the Dry Voltaic Piles of M. Zamboni. — The following is 

 part of a report made by M. Ampere, on a memoir relative to the 

 above voltaic combinations. 



The energy of these dry piles ceases to diminish after two 

 years ; such, at least, M. Zamboni finds to be the case during 

 twelve years' experience. 



The diminution in the two first years varies according to the 

 manner in which the pile is constructed. 



The pile is more energetic in summer than in winter, both with 

 regard to the intensity produced, and the promptitude with which 

 it is manifested. 



The tinned paper, called silvered paper, with black oxide of 

 manganese, developes an electric force very superior to that ob- 

 tained when the paper is covered witli a thin leaf of copper ; the 

 latter is known under the name of gilt paper, (Dutch gold 

 paper.) 



A pile formed of discs of paper, tinned on one side, without 

 any interposing substance, produces electrical effects, which can 

 result only from the circumstance that the metallic leaf, glued 

 to the upper surface of the paper, touches it more intimately than 

 it does the lower surface of the paper belonging to the element 

 next placed above. 



M. Zamboni has examined whether in those piles, which he 

 calls binary, the action of the elements takes place as in those 

 which are composed of leaves of tin, covered with oxide of man- 

 ganese, or in the reverse order. He found that one or the other 

 of these results could be obtained at pleasure, by imbibing the 

 paper attached to the tin, with various substances. When oil 

 was used the action was opposed to that produced by oxide of 

 manganese ; when, on the contrary, the paper was imbibed with 

 honey or alkali, a solution of sulphate of zinc, or milk in a 

 semi-coagulated state, the binary pile acts like those composed 

 of elements powdered with oxide of manganese. 



By using a dry pile of 1000 pairs, the plates not being more 

 than five or six centimetres, (from two to two and one-third of 

 an inch,) in diameter, M. Zamboni obtained by the condenser 

 sparks of an incli in length, so that with such a pile an electric 



