Notices respecting New Books. 139 
“appears explielé and impartial. Mr. Singer has given it under 
the general title of Galvanism, because it originated entirely 
_ with the experiments of the learned professor of Bologna. Under 
the arrangement which is here given to it, Galvanism certainly 
forms a Mery. jie gs introduction to the fourth and last part of 
Mr. Singer’ s work, which has for its subject ‘ Voltaic electricity.” 
This subject, the most novel, and to many the most interestiag 
before us, is discussed in four chaptars under the following titles: 
Chap. }. Structure of the Voltaic apparatus, and nature of its 
electrical phenomena. 
Chap. 2. On the chemical effects of the Voltaic apparatus. 
Chap.3. Extensive agency of the Voltaic apparatus as an in- 
strument of chemical analysis. Its influence in the evolution of 
light, and the production of heat, 
Chap. 4. Sketch of the state of theoretical knowledge in Vol- 
taic electricity. Structure and properties of the electric column, 
~The construction of the various parts of the Voltaic apparatus 
is described in clear terms, and a particularly full account of the 
process of cementing the trough is given. 
The author prefers the original trough of Cruickshank to that 
 iirined on the principle of the cowronne de tasses, which is at 
present so much in use. In the former, all the plates being aeted 
on at one surface only, each produces its full proportion of effect, 
‘and continues for some time active: in the latter, one surface 
of the zinc is wasted to very little purpose; the acid is sooner 
saturated, and its action is consequently more transient. To de- 
monstrate the electrical effects of the Voltaic battery, Mr. Singer 
employs river water only, as the medium of connexion between 
his plates, and finds it preferable for this purpose to any acid 
mixture. ‘ With a series of 50 groups a delicate gold-leaf elec- 
trometer will be affected without the aid of the condenser. With 
100 pairs the divergence of the gold-leaves is sufficiently distinct ; 
and with a series of 1000 groups even pith balls are made to di- 
verge. In these experiments, a wire proceeding from one extre- 
mity of the battery is to be connected with the foot of the electro- 
meter, whilst a wire proceeding from the opposite end is brought 
to touch its cap. The electricity of the zine side is always po- 
sitive ; that of the copper side always negative.” By employing 
ater in his Voltaic apparatus Mr: Singer has discovered that 
the powers of that apparatus may be accumulated in an electrical 
battery, which, when connected with it, will always be charged 
highly than the apparatus itself, producing loud sparks, 
burning metallic leaves, when the Voltaic series employed 
© communicate the charge to it has no such power alone. 
his method of employing the Voltaic apperatus is a very ex- 
cellent 
