58 Notices respecting New Bovks. 
tific exposition of the science. The work itself is divided inte 
four parts, which are again subdivided into chapters. The first 
part describes “ electrical phenomena and the circumstances 
.essential to their production.” This part is divided into five 
chapters, arranged as follows : ‘ 
Chap. I. Nature of electrical action and sources of electrical 
excitation ; positive and negative electricity. 
Chap. II. Of conductors and non-eonductors of electricity, 
and of the electrical apparatus. 
Chap. III. Experiments with the electrical machine.—Theory 
of its action.—Phznomena of attraction and recession. 
Chap. IV. On the phenomena of electric light. 
Chap. V. On the Leyden jar and the nature of electrical 
influence. 
This part of the work is chiefly remarkable for the distinct 
arrangement which it presents, and for a carcful selection of 
experiments which are explained very clearly by a judicious mo- 
dification of Dr. Franklin’s theory, ‘The distinguishing charac- 
ters of electrical action are described as consisting in the at- 
traction of light substances and the emission of light, the re- 
pulsion or separation observed between electrified substances 
being ascribed by the author to the attraction of the surrounding 
air or other medium, and not to any repulsive power, the existence 
of which, he asserts, is purely hypothetical. In this opinion he 
is supported by the authority of Kinnersley, Morgan, Volta, and 
De Lue, and by the experiments of Lord Stanhope, and it cer- 
tainly renders the explanation of many phenomena much more 
simple and satisfactory. ; 
The chief sources of electrical phenomena are; Ist, Friction. 
2d, Change of form. 3d, Change of temperature. 4th, Con- 
tact of dissimilar bodies. It is the last which our author con- 
siders as in all cases the primary cause of electrical excitation 5 
for it occurs in all the others ; and in the most simple case of 
electrical action, that of De Luc’s electrical column, the contact 
of dissimilar bodies is the only known cause of the effects pro- 
duced. ‘ 
In the table of the effects of excitation, some corrections of 
the results given by Cavallo are made; but the author has not 
rendered it either so complete or perfect as we were led to ex- 
pect from our knowledge of the extent of his experience. 
A variety of experiments are adduced to prove that positive 
and negative electricity are always produced together, and the 
phenomena resulting from the action of a Nairn’s machine are 
minutely described as affording the following indications : 
1. That the cause of electricity is corporeal; for sensation 
is affected by it, and a mechanical impulse is experienced. 
2. That 
