Notices respecting New Books. 405 



speaks of electro-chemistry as being " a bond between physics and 

 chemistry." He says, that formerly our experiments were carried 

 on by large, but now by small series of Volta's pairs, and thus are 

 our operations easier of practice. He intends treating on all simple 

 bodies, beginning with the metals, and of those with gold. He al- 

 ludes to certain principles established in former papers, and pur- 

 poses showing the application of electro-chemistry to the arts, as in 

 assaying, gilding, &c. He dwells in his introduction upon the che- 

 mical theory, and adduces two important facts in confirmation of its 

 truth ; — 1st, that there is no chemical action without a considerable 

 disengagement of electricity ; 2nd, that a Volta's pile, charged with 

 a liquid not acting chemically on either of the two elements of which 

 each body is composed, does not become charged, that is, produces 

 neither current nor electricity of tension. If one of the two ele- 

 ments is attacked, even very feebly, by the liquid, the effects of cur- 

 rent and those of tension immediately follow. As the chemical 

 action increases, so do the electrical effects. He offers an observa- 

 tion, due to his son Edward, which he considers of much weight in 

 favour of this theory. "When one substance acts on another, under 

 the influence of light, electrical effects are produced, as in all che- 

 mical reactions, which effects are manifested so long as this influ- 

 ence remains. If it ceases to exist, there is no longer any sign of 

 electricity, and nevertheless the contact of the newly-formed sub- 

 stances with the metallic plates, still exists, and nothing is changed 

 in the circuit." He then introduces gold, its extraction from the 

 ore, and the modes of assay, illustrated by several experiments "of 

 his own upon the ores of the Oural and the Altai, in order to exa- 

 mine the nature and extent of the stamping and washing best fitted 

 to produce least waste. He then adverts to amalgamation, &c, and 

 proceeds to the further execution of his task, at which point the 

 present translation ceases, the remaining portion being reserved for 

 a future meeting. 



An abstract of observations on the degree of identity between 

 electrical and chemical affinity, by Mr. Prater, M.E.S., was read. 



Mr. Weekes's Electro-Meteorological Journal for September was 

 laid before the Society. 



LXX. Notices respecting New Books. 



The Difficulties of Elementary Geometry, especially those which concern 

 the Straight Line, the Plane, and the Theory of Parallels. By 

 Francis William Newman, Tutor at Manchester College. 

 Longmans. 



THE philosophy of our mathematical processes is far from being 

 a favorite subject of investigation in this country ; though 

 amongst the continental geometers it is cultivated with singular 

 predilection. There are, however, two aspects under which this 

 class of inquiries may be viewed ; or more properly, two distinct 

 branches of the inquiry, which seem to require faculties of a consi- 

 derably dissimilar kind. The first class is that in which the logical 



