2 Mr . Cavallo’s Ohfervntions on 
the laws of a fcience aimed entirely unknown before. Various 
wonderful phenomena of nature have been explained, means 
have been difcovered of avoiding fome of their dangerous 
effects, and a greater inlight into the general operations of 
nature has been derived, from the knowledge of fo great and 
fo extend ve a power as is commonly underdood under the 
name of elettricity ; yet, if indead of contemplating its more 
flriking phenomena, viz. thofe which are apt to furprife more 
by the magnitude of their effects, than by the indruCtion 
which they may afford, we endeavour to examine the fubject 
more clofely, we (hall find that our knowledge of electricity 
goes very little, if at all, beyond the fuperficial part of it- 
We know, for inftance, that a piece of glafs, or other eleCtric, 
when rubbed, will produce that power which we call eleCtri- 
citv, that the glafs will communicate the acquired electricity 
to a piece of metal, that the piece of metal will retain that 
power in certain circumftances, and fo on ; but no perfon has 
(hewn how that power is generated by the friCtion, or what 
prevents its paffage through the fubdance of fome particular 
bodies. It has been afcertained, that the air of moil coun- 
tries, and probably of the whole world,, as well as the clouds,, 
fogs, rains, &c. are almoft always eleClrified ; but we are 
Ignorant of the office which this eleClricity can have in the 
great laboratory of nature ; for furely fo general and fo aCtive 
a powder can hardly be intended by nature, merely to intimi- 
date mankind now and then with the thunder and the light- 
ning. 
It appears, therefore, that thofe perfons, w r ho are now 
willing to didinguiffi themfelves in this intereding branch of 
natural philofophy, ought to examine the cleChical power not 
to much in its accumulated, as in its incipient date. Its firft 
5 • origin. 
