New Outlines of Chemical Philosophy. 273 



wade with this instrument, from which it appears that electricity 

 by induction is permanent, and does not vanish on removing the 

 exciting cause*. 



But to ascertain the truth of this principle wnth still greater 

 precision, I made a great numl^er of instruments (more than 

 twentv) of a more perfect construction than tiiat above de- 

 scribed. Some of these remained electrified by induction for 

 two or throe hours ; but others retained the electrical element 

 which thev had received by induction, for almost three days. 



Exp. \. To determine the sensibility of these instruments, 

 I placed one of them close to an electrometer constructed ac- 

 cording to Mr. Benuet's directions f ; and after having slightly 

 excited a barometer tube, i placed it at tbe distance of about 

 two or three inches from the top of each. The indexes of miu« 

 rose to ISO degrees, being the extent of the scale, and remained 

 permanently electrified ; but no permanent effect was produced 

 on Mr. Bonnet's, nor even any perceptible effect, when the air 

 was damp, and unfavourable for electrical experiments. 



Erp. 2. Two of tliese electrometers, which were differently 

 constructed in some respects, being placed upon a table, and an 

 excited glass tube carried over them at the distance of a few 

 inches, one of them received the same element as the excited 

 tube, but the other received the contrary element, and they re- 

 mained permanently electrified |. 



This seeming paradox may be explained thus : If a very small 

 piece of metal be properly insulated, the quantity of electricity 

 which it contains in its "natural state, may be deemed almost 

 nothing; and therefore it receives electricity from the excited sur- 

 face, of the same kind as it would receive by direct communica- 

 tion. But when a brass ball of one or two inches in diameter 

 is insulated, and an excited surface brought near it, the two ele- 

 ments, diffiased over its surface, begin to be separated. The 

 element of the same kind as that of the excited surface is re- 

 j)elled into the atmosphere, but the other clement is detained 

 upon the surface of the ball ; and consequently, as soon as the 

 excited surface is removed, the hall remains permanently elec- 

 trified, and in a state contrary to that of the exciting cause. 



Now, as tbe laws of nature are the same, whether their ope- 

 rations ap})ear in our experiments or upon the grand tlieatre of 

 the universe, the above experiments may, therefore, lead us to 

 an explanation of some meteorological phrenomena, which are 

 inexplicable upon any other known principle. 



Suppose a very dense cloud (A) be electrified either by its 



* Phil. MaK vol. xlii. p. '.115. t Pliil. Trans, vol. Ixxvii. 



J A tmthrr account of tltcse elcctromttcrs will be given at some futur* 

 •jiportiinity. 



Vol.44. No. ins. Of^ 1814. S proximity 



