Scientific hitelligencc. — Natural Philosophy. 357 



out the assistance of the condenser. The consequences which 

 result from these two series of experiments, with respect to the 

 idea to be formed of the principal cause of the development of 

 electricity in the pile, are evident, and appear to us to be of a 

 nature to modify the ideas of the learned world respecting one 

 of the most important facts in natural philosophy. 



3. Influence of Meteorological Phenomena on Dry Piles. — 

 M. Donne lately read to the Academy of Sciences, a memoir, 

 entitled Inquiries respecting the Influences which Meteorologi- 

 cal Phenomena exercise on Dry Piles. The dry piles invented 

 by M. Zamboni had not hitherto been sufficiently studied with 

 reference to the variations which their tension undergoes from 

 the influence of meteorological phenomena. It was therefore 

 of importance to determine, by experiments directed toward 

 this object, what is the particular action of humidity, tempera- 

 ture, atmospheric weight, and electricity, upon that instrument, 

 and then to observe it during a long period when under the in- 

 fluence of all these causes together. The first part of this me- 

 moir comprehends the result of these experiments : in the second 

 it is inquired whether the dry piles may be compared to the 

 voltaic pile, and if it is possible to make it produce some che- 

 mical action. — Humidity. Humid air acts only as a conduct- 

 ing body, by carrying off" more or less electricity, and not by 

 modifying the function of the pile. — Atmospheric weight. There 

 is no relation between the variations of tension of the dry piles 

 and the barometric heights. If a pile is placed under the bell 

 of a pneumatic machine, and a vacuum is made, it experiences 

 no diminution in its tension, even when the vacuum is kept up 

 as exactly as possible for several days. This is in contradiction 

 to the well known experiment, which tends to prove that air 

 is necessary for forcing the electric fluid into the conductors; 

 but the fact is constant, and has been verified by repeated ex- 

 periments. — Temperature. Of all the atmospherical circum- 

 stances this acts in the most diversified and most immediate 

 manner upon the dry piles, and its action is extremely compli- 

 cated. In fact, experiment and observation have demonstrated, 

 1st, That its effects are different according as the variations are 

 quick and instantaneous, or take place slowly and progressively. 

 In the former case, the tension of" the pile is considerably dimi- 



