i88 3 .] 
Analyses of Books , 
615 
Electricity and its Uses, By J. Munro. London : The Reli- 
gious Trad! Society. 
We have here a popular, but clear and corredt, account of elec- 
trical science in all its various branches. A work of this kind 
was greatly needed. We have indeed, in the English language, 
books which treat of electricity in a manner suitable for the 
student or for the professional specialist ; but if an educated and 
intelligent non-specialist had asked us to recommend him a book 
giving a brief and plain account of the recent applications of 
eledtricity, of their results, and of the principles upon which 
they rest, we should have felt no little perplexed. 
Hence it is no wonder if the popular notions of electricity are 
of the wildest. It is credited with the strangest and the most 
contradictory attributes, and is recommended by those who know 
least about it for effecting any purpose soever. We trust that 
some at least of these vain imaginings will fade away into the 
“infinite azure” as Mr. Munro’s little book becomes better 
known. 
The author’s plan is very simple : he describes and illustrates 
the leading properties of the agency in question, and then pro- 
ceeds to show their applications. Thus we have, first, a sketch 
of the early history of the science, a notice of the rival hypo- 
theses of two fluids, and of one which, though no longer recog- 
nised by electricians, still survives, for convenience sake, in their 
current language. We are then successively introduced to bat- 
teries, to polarisation, circuit, resistance, the electromotive force, 
and Ohm’s law. In successive chapters follows an account of 
induction, a notice of the telegraph, telephone and microphone, 
of the photophone and telephotograph, the induction balance, 
the dynamo-eleCtric machine, the various arrangements for the 
generation of the eledtric light, and a summary of its advan- 
tages as compared with gas, — once the admiration of our fathers, 
but to us a mere nuisance, especially where supplied by a mono- 
polist company. 
We have next an account of the applications of eledtricity for 
the transmission of power and for storing up the effedt of certain 
natural agencies, such as the winds, the tides, waterfalls, &c. 
It may here be mentioned that Mr. Edison hopes ultimately to 
obtain an unlimited supply of power from the eledtric currents 
of the earth and the atmosphere, thus dispensing with the steam- 
power and the consequent consumption of coal for setting 
dynamo-machines in adtion. The transmission and distribution 
of mechanical power — just as we now lay on water or gas — 
rightly seems to Mr. Munro to open up a hopeful social prospedt. 
He writes: — “ The great economy of very large steam-engines 
over small ones has led to the development of large factories, 
where hundreds of human beings are cooped up amid the in- 
