VOL. LIl.] PHILOSOPHICAL TRANSACTIONS. 5fti 



published a treatise, of which the present work may be considered as a continua^ 

 tion. That consisted of 9 letters on the subject of electricity, which were ad- 

 dressed to persons who had distinguished themselves by their endeavours to illus- 

 trate this part of natural philosophy. In like manner, the present performance con- 

 sists of 8 letters, and is addresed, as the former, to his friends and correspondents. 



As an account of the former treatise was communicated by myself to the Royal 

 Society, and printed by direction of the council in the Phil. Trans.,* the author 

 requests, at the end of the 1 6th letter, which is addressed to me, that I would 

 give myself the additional trouble to lay before you an account of the present 

 work. This request I most readily comply with, not only in obedience to the 

 order of the society, but likewise as a testimony of the esteem and regard which 

 I have long entertained, and shall continue to do, for the excellent author of it. 



This treatise, like the former, is printed in 1 2mo. and contains 284 pages ex- 

 clusive pf the preface and 4 tables exhibiting 14 figures. The principal design 

 of the work is to support and further confirm the hypothesis of the author, and of 

 several other persons who have considered these matters, that the effects of electri- 

 city depend on the simultaneous affluence and effluence of the electric matter. 



In defending his opinions in regard to the effects of electricity, the Abbe NoUet 

 has given a variety of new experiments, which cannot but be agreeable to those 

 who are conversant in these matters. He has also occasionally mentioned those 

 of other persons, which are come to his knowledge, and which he apprehends not 

 to be sufficiently known. He has traced the origin of several happy inventions, 

 and has exhibited the real authors of them. He has given, as he imagines, 

 additional value to several experiments which appear to have been too much neg- 

 lected ; and brought others which have been over-rated to their proper standard. 



As this work is of a controversial kind, the author has had particular attention 

 to such points as have been the occasion of contest ; to weigh the reasons of his 

 opponents, and to add new explanations to such of his opinions as seem to want 

 them ; more particularly to such as have appeared to him to have been mis- 

 understood. 



The first of these letters is addressed to M. Necker, professor of experimental 

 philosophy at Geneva. In this letter, our author endeavours to establish his 

 opinion published long since, in regard to the existence of the simultaneous afflu- 

 ence and effluence, and consequently the double current of the electric matter 

 in opposite directions. And herein our author by a series of experiments, 

 obviates some doubts which had occurred to M. Necker in respect to the validity 

 of this hypothesis. 



The 2d letter is addressed, as the former was, to M. Necker of Geneva. In 



* Vide Vol. XLViii. p. 202. 



