264 Notices of Books. ‘April, 
for its basis an observed relation of phenomena, or the elements 
of phenomena, in a greater or less number of cases; and the 
inference asserts what will take place in all similar cases. In- 
ductive inference affirms, regarding all instances of a particular 
kind, what is observed to be true of a certain number of instances 
of that kind.” Then as to deduction, ‘‘ here the mind passes in 
reasoning from the general or universal to the particular.” Thus 
the chemist, having discovered the general laws of chemical 
combination, can predict the result in particular cases; and the 
naturalist, having ascertained the universal characteristics of 
some species, may with certainty expect to find these character- 
istics in any new specimen of this species. A short summary 
is given at the end. The matter is clearly stated, and the book 
will be found useful to all those students who intend to take up 
that vast and not too profitable study of philosophy. 
Transits of Venus. A Popular Account of Past and Coming 
Transits, from the first observed by Horrocks, a.pD. 1639, to 
the Transit of A.D. 2012. By Ricuarp A. Proctor, B.A. 
With 20 Plates and 37 Woodcuts. London: Longmans, 
Green, and Co. 1874. 
WE have before us another of those carefully written and beau- 
tifully illustrated books which Mr. Proctor, from time to time, 
provides for the purpose of popularising more or less abstruse 
science. This work can hardly hope to appeal to so large a 
section of the public as his *‘ Sun,” ‘* Moon,” &c., for the subject 
is one that rather concerns the astronomer than the general 
public; the objects at issue do not bear so directly upon every- 
day life; and if a man has never seen Venus, and has no chance 
of ever seeing a transit, and does not easily comprehend how 
his race can be benefitted by a knowledge of an exacter deter- 
mination of the sun’s distance (which need not have a greater 
error than 100,000 miles), then we say he is not likely to trouble 
himself about the subject at all. But if any book is likely to 
create an interest on the subject, and to make it popular, that 
book is surely Mr. Proctor’s. 
Economic Geology, or Geology in its Relations to the Arts and 
Manufactures. By Davin Pace, LL.D., F.G.S., &c. Edin- 
burgh and London: W. Blackwood and Sons. 
As the Author remarks in his Preface, ‘‘ There are works on 
agricultural geology, on building and decorative, on mortars and 
cements, on coal-mining, on veins and lodes, and on ores and 
metallurgy, but there is no general treatise on geology in its 
numerous relations to the arts and manufactures.” This defi- 
