C 337 ] 
the efteem and regard, which 1 have long entertained, 
and fliall continue to do, for the excellent author of it. 
The principal defign of the work before us, is to 
fupport, and further confirm, the hypothecs of the 
author, and of feveral other perfons, who have con- 
fidered thefe matters, that the effects oj electricity de- 
pend upon the ffmultaneous affluence and effluence of 
the eleCiric matter. This treatife, like the former, 
is printed in i2mo. and contains 284 pages, exclufive 
of the preface, and four tables, exhibiting fourteen 
figures. 
In defending his opinions, in relation to the effects 
of eledtricity, the Abbe Nollet has given a variety of 
new experiments, which cannot but be agreeable td 
thofe, who are converfant in thefe matters. He has 
alfo occafionally mentioned thofe of other perfons, 
which are come to his knowledge, and which he ap- 
prehends not to be fufhciently known. He has traced 
the origin of feveral happy inventions, and has exhibited 
to us the real authors of them. He has given, as he 
imagines, additional value to feveral experiments, 
which appear to him to have been too much negledted; 
and brought others, which have been over-rated, to 
their proper ftandard. 
As this work is of a controverfial kind, the author 
has had particular attention to fuch points, as have 
been the occafion of conteft ; to weigh the reafons of 
his opponents, and to add new explanations to fuch 
of his opinions, as feemed to want them; more par- 
ticularly, to fuch as have appeared to him to have been 
mifunderftood. 
The firft of thefe letters is addrefTed to M. Necker, 
profeffor of experimental philolophy at Geneva. In 
V o l. LII. X x this 
