ATMOSPHERIC ELECTEICITY. 343 



powder, acquire by their friction an electricity perceptible by the elec- 

 troscope, there is nothing to show that the same Avill not be the case 

 even from the friction of the liquid particles against each other, or of 

 the liquid particles against the ])articles of air. Besides, an electricity 

 as strong as that which is exhibited by the spray of the cascades would 

 be scarcely in proportion to so feeble a cause of development. As 

 for the second explanation, which is the one given by Volta, and which 

 Schiibler also adopted, besides that it rests on the hypothesis of the 

 development of the electricity, in the formation of vapor, a num- 

 ber of other objections may be made, to which it is difficult to give 

 a satisfactory answer. Thus it appears impossible to conceive how 

 the drops of water in simply falling from the height of some hundred 

 feet can become electrified by evaporation, so as to produce an elec- 

 tricity as strong as that which has been observed during storms, and 

 even stronger than that which is ordinarily exliibitcd in the drops 

 of rain which fall from a height incomparably greater. 



As we have already said, M. Becquerel found in the negative elec- 

 tricity of falls of water a proof of his theory of the formation of nega- 

 tive clouds. According to him, this electricity proceeds from that 

 which the earth habitually possesses. The water, in falling with great 

 velocity on the rocks, is scattered into vesicular globules, which carry 

 with them into the atmosphere the negative electricity which they 

 have taken from the rocks. M. Becquerel drew from this the con- 

 clusion that the vapor which is formed at the surface of the globe 

 may, in the same way, carry away a portion of the negative elec- 

 tricity of the earth. 



This explanation has been opposed by M. Belli,* who believes that 

 the electrical phenomenon of the water of cascades is owing to the 

 development of electricity by the induction which the positive electricity 

 of the atmosphere exercises on the water. " The water," he says, 

 "is by induction in the negative state, when the atmosphere is as it is 

 ordinarily, charged with positive electricity. At the moment when 

 this water divides into thousands of minute drops, it cannot fail to carry 

 the electricity with whicli the electrical induction of the atmosphere 

 has impre<::nated it to all the bodies which it meets." M. Belli made 

 some experimental researches in support of his opinion. He arranged 

 in an uncovered place, and under a clear sky, a portable fountain. 

 He then discharged a jet of water slightly inclined from the perpen- 

 dicular, and collected the drops which escaped in an insulated vessel, 

 communicating with a Leyden phial. On examining it with the con- 

 denser, he ascertained that the droj)s of water were very perceptibly 

 negatively electrified. When the compressed fountain was insulated 

 and put in communication with an electroscope, he obtained a very 

 marked divergence of positive electricity, which was reproduced every 

 time it was destroyed by momentarily touching with the hand the ball 

 of the electroscope. According to i\l. Belli, tiiese experiments demon- 

 strate that the column of ascending water becomes electrified by the 

 electric induction of the atmosphere. To show that tiie evaporation 

 of the water was of some importance in this phenomenon, he repeated 



■5 Bibl. Univ., Nmivcllc Serie, torn. VI, page 148. 1836. 



