§Qi rws nxrvnkL bistosy of ccouos. 



increasing miVil sparks were emitted more freely tlian before. 

 This charge continued during the passage of the hail, 

 and went off gradually as soon as it was clear of the in-? 

 siruraent. After having closed, the balls opened again 

 negative, and this charge jncreatjed to a considerable inten- 

 Sfty, as the shower receded towards the south and south-west, 

 after which it gradually went off: the balls closed, and finally 

 were left slightly positive. From these facts, the reader, 

 who is conversant in electricity, will deduce the structure of 

 the lower part at feast of the shower. He will see, that the 

 descending hail formed a column positively electritied. 

 This, which might be six or seven miles in diameter, was 

 surrounded with a cylinder of negative electricity, probably 

 extending in every direction three miles farther, and result- 

 ing from the action of the positive centre on the dry atmo- 

 sphere, in which it was moving. Now the amount of the 

 hail, when melted, was considerably less than x^Tj-^h of an 

 inch in the rain gauge ; and could the descent of the electric 

 fluid through the whole space have been rendered as ob- 

 vious to our senses as that of the hail, we should probably 

 have said, that the shower consisted of fire more truly than 

 of ice. 

 WTience th« The question that naturally presents itself is, Whence 

 eeLcnci y. ^ame this flood of electricity which accompanied the hail? 

 It was not from the circumstance of the water being frozen, 

 since a hard shower of rain equally exhibits a charge, but 

 with this remarkable difference, that whereas snow, sleet, 

 and hail, are alwavs positive, rain is found sometimes positive, 

 sometimes negative. Thcr* reader may consult, on this 

 head, an extensive collection of facts in Read's Journal of 

 Atmospherical Electricity, " Phil. Trans." Vol. LXXXII. 

 The probable Bonrces of negative rain will be presently 

 raentioned ; b(it to return to the question of the origin of 

 the positive charge; if we attentively consider the structure 

 of the nimbus, it is precisely that which, from the known 

 properties of the electric fluid, we should propose for a con- 

 ductor formed to acquire the latter. If we detach from it 

 the falling column, and extraneous clouds which usually 

 attend its progress, it will be found to consist of a close col- 

 lection of fibres, diverging from the region of the cumulus, 

 "'" (where. 



