REVIEWS, 
259 
Chapters written in the same slipshod style follow, on Thermo-electric bat- 
teries (5 pages), magneto-electric generators, electro-magneto-electric ma- 
chines (6 pages), dynamo-electric machines, evidently gathered from familiar 
sources, containing nothing new except what is not true ; and so at the 150th 
page we arrive at some 1 general observations on machines.’ Here, at last, 
we meet with traces of practical, if not of theoretical knowledge, such as re- 
commendations 1 to start the machine with open circuit,’ and ‘ never to place 
the machine at full speed on short circuit,’ to drive steadily, and to use sperm 
oil for lubrication. 1 A machine that heats much is not properly constructed, 
and may be improved by taking a layer of wire off the electro-magnet.’ 
Chapter VIII. deals after the same fashion with 1 electric lamps and candles,’ 
naming those best known, and omitting, as usual, their common ancestor, the 
Chapman lamp, already figured in this journal. The author contributes a 
lamp about as good as his battery. Of this invention it is naively said, 
* When the lamp has given light for about six hours or more, and it is re- 
quired to continue for another six hours, it is only necessary to slightly lower 
the plates by the screws in the armatures. In practice this canmot le done 
just as directed .’ 
Mr. Edison is dismissed very cavalierly. 1 Much interest,’ says our 
author, ‘ has been taken in the sensational and often absurd announcements 
concerning the apparatus in course of perfection by Mr. T. A. Edison, of 
Menlo Park, New York. This inventor is well known by his talking phono- 
graph (sic) and telephones, and it was in some quarters thought that when 
he had set himself to the task of inventing an efficient subdivision of the 
electric light circuit, something would in all probability be done. Unfortu- 
nately, however, as far as can be learned up to this date (July, 1879), the 
attempts have proved almost complete failures.’ 
In Chapter IX. we have nine pages on the measurement of the electric 
light, in which Rumford’s and Bunsen’s photometers are very feebly described, 
followed in Chapter X. by eleven pages on the 1 mathematical and experi- 
mental (sic) treatment of the subject.’ Hopkinson, Schwendler, Preece, and 
Siemens, are laid under contribution, but to very little purpose. The book 
concludes with about a dozen pages on the cost of the light. The quantity 
of information given in 290 pages is infinitesimally small. 
Messrs. Crosby and Lockwood deserve much credit for the getting up of 
the book. The print is excellent, the paper beautiful, the woodcuts superb. 
Their motto on the title-page is Capio lumen — it would have been better in 
this case had they modified the first word to Rejicio . W. H. Stone. 
BRITISH COPEPODA.* 
TN the course of the thirty-six years of its existence the Ray Society has 
certainly well fulfilled the purpose for which it was established. A 
great number of copiously, and often most beautifully, illustrated monographs 
* A Monograph of the Free and Semi-parasitic Copepoda of the British 
Islands. Bv G. Stewardson Brady, M.D., F.L.S. 2 vols. 8vo. London : Ray 
Society. 1878-1880. 
