48 
Analyses of Books. 
[January, 
Mr. P. H. MacGillivray, F.L.S., contributes two pages in 
continuation of his description of new or little-known polyzoa. 
The rest of the papers, with the exception of Mr. Ellery’s 
notes on the Rainfall Map issued by the Government of Vic- 
toria, contain little or nothing which might not have been 
worked out fully as well in Europe. What the world naturally 
expects from the colonial learned societies is research con- 
cerning local phenomena — meteorological, geological, and, 
above all, biological. 
Exercises in Electrical and Magnetic Measurement. By R. E. 
Day, M.A. London : Longmans, Green, and Co. 
The work before us owes its origin to the increased attention 
paid to the study of elecftricity and magnetism. The author 
enters upon his task with an explanation of the units now 
employed in electrical measurements. It may be that the 
names of eminent physicists have furnished the most conve- 
nient designations for some of these units. But we should 
not like to see the principle extended. It would sound strange 
if we were to hear a certain quantity of hardness in water spoken 
of as a “ Clarke ” — a standard “ previous sewage contamination ” 
described as a “ megafrankland.” 
After this preliminary explanation Mr. Day gives in succes- 
sion problems illustrative of electrostatics, of the tension 
balance, of statical induction, the guard-ring electrometer, 
electrical discharges, moments of tension and inertia, mag- 
netism, resistance, and conductivity, branch circuits and 
shunts, currents in simple circuits, currents in branch circuits, 
the special grouping of cells, volta-meters, and electrolysis, and 
the chemical theory of electromotive force, thermo-electricity, 
battery resistance, electro-motive force, electro-magnetic mea- 
surement, magneto-electric induction, and the distribution of 
heat and work. 
When used in connection with actual laboratory work this 
treatise will be found exceedingly valuable. 
