cellent one; for it maintains its action without any renewed at- 
‘tention for months, and probably for years: and as the effect in- - 
ereases with the number of plates employed, Mr. Singer suggests 
that, by employing 50 or 100,000 plates, a considerable charge 
might be constautly kept up in an electrical battery, and that at. 
no expense but the first cost of the apparatus ; w hich would be 
sufficient if formed of plates two inches syuare. 
In noticing the chemical action of the Voltaic apparatus it is 
remarked, that its operations are very different to those of com- 
mon electricity, which are usually attended by mechanical action, 
and rarely by any unequivocal production of heat ; whilst in the 
Voltaic apparatus when no light is evolved an elevation of tem- 
perature may be usually observed: and when by its intense ae- 
tion there is a copious evolution of light, heat is produced in a 
superior degree to that which results from any other process of 
art. When metals are revived from their solutions by Voltaie 
electricity, it is noticed as a singular fact, that none but lead, 
tin, and silver, appear as brilliant metallic vegetations. The 
Various experiments of decomposition and transfer, with the in- 
teresting discoveries of Sir H. Davy, are detailed with great ac- 
euracy and perspicuity, accompanied by occasional observations — 
of the author which tend considerably to the elucidation of the — 
subject. So much information is indeed included in this parf. | 
of the work, that we have no wish to lessen the interest it is cal- 
culated to excite, by giving a series of abridged extracts from 
that which should be read in its complete state. Considerable _ 
attention is given to the experiments and observations of Dr. 
Wollaston, Sir H. Davy, and others who have made useful re- | 
searches‘on the subject. The facts throughout appear to be — 
stated with great impartiality, and the remarks and experiments. — 
of the author evince a very perfect acquaintance with his sub-.— 
ject, and habits of research and inquiry which cannot fail to — 
render an essential service to the cause in which they are em- — 
ployed. We are pleased to observe that no attempt is made to, 
add to the various hypotheses that have been advanced to ac- | 
eount for the phenomena of. Voltaic electricity: the experiments 
and observations of the author appear rather to support the 
opinions of Volta; yet no hypothesis is insisted on, but the 
deficiences of the principal ones that have heen proposed are. | 
noticed very freely, and with a spirit highly characteristic of the 
independent feelings of the writer. 
The ingenious analysis of the Voltaic apparatus by our valu- 
able correspondent, M. De Luc, is noticed with considerable ap- | 
probation by Mr. Singer, who has extended the experiments of — 
that venerable Paalasaphier, and confirmed the accuracy of his | 
results, p 
140 Notices respecting- New Books. is : 
