Sckntljic Intelligence. — Natural Philosophy. 359 



traded by the opposite electricity ? The earth's surface must 

 thus present, at the place where a thunder-storm exists, a positive 

 or negative fluid, which recomposes itself with the electricity of 

 the clouds, when the rain furnishes it with a conductor. This 

 fact may be verified by direct experiment, since it is sufficient, 

 during a thunder-storm, to put a very sensible electrometer in 

 connexion with the common reservoir, to obtain signs of elec- 

 tricity. It is true, that it is not during thunder-storms that 

 the great changes take place in the variations of the tension 

 of dry piles. But is it not possible that there may be thun- 

 der-storms in the bowels of the earth, as there are in the 

 atmosphere .'' That in earthquakes especially, great decomposi- 

 tions of electric fluid take place, which respond at great distan- 

 ces, and which act upon our instruments much more powerfully 

 than the thunder-storms of our atmosphere ! But it will al- 

 ways be very difl^lcult to arrive, in this matter, at a sure result, 

 seeing it is impossible for us to know how the electric fluid is pro- 

 pagated and distributed in the strata of the earth, which are so 

 diversified, and since an effect which is produced here may be 

 very imperceptible elsewhere, besides that it must often happen 

 that the effects of temperature are confounded with others. It 

 appears demonstrated, however, that the earth being capable of 

 furnishing electricity to the dry piles in certain cases, their ten- 

 sion may be augmented or diminished. May Zamboni's appa- 

 ratus produce some chemical action, and may its action be com- 

 pared to that of the Voltaic pile .^ A string formed of fifty^two 

 dry piles, of a thousand plates each, gave strong sparks, but its 

 chemical action was absolutely null. It was even impossible, 

 by employing WoUaston's method, to decompose water, or change 

 the colour of the weakest tinctures. It is not here that force is 

 wanting to act chemically upon the bodies ; it is that there is 

 no current in the dry piles, as is understood to be the case with 

 Voltaic electricity : their action is entirely that of tension, and 

 not at all galvanic. To form a proper idea of the dry piles, 

 they must not be compared to the Voltaic pile, but to an elec- 

 trical machine, which is recharged of itself. The current which 

 it produces is but a series of discharges, a series of sparks which 

 follow each other, at very short intervals, and which, for this 

 very reason, cannot produce any chemical effect. 



