no 
Notices of Books. [January, 
1 835 , when vaccination was comparatively rare, small-pox epi- 
demics were commonly spoken of as a thing of the past, and a 
pitted face among young people was almost unknown. These 
facts have not been satisfactorily explained, and any additional 
light is therefore welcome. Mr. Sprague, however, after a careful 
examination of the statistics of the case, draws no very decided 
conclusion.. He thinks the inferences condemnatory of vaccination 
founded by Dr. Keller on the vital statistics of the employes of 
the Austrian State Railway scarcely warranted by the figures, but 
admits that the Doctor has established that “ the rate of mortality 
among the vaccinated persons who were attacked was quite as 
heavy as that among the unvaccinated.” In English statistics, 
and in the comments made upon them, he can “ see nothing that 
at all explains why, notwithstanding the introduction of com- 
pulsory vaccination, the deaths from small-pox should have risen 
in the year 1872 so far beyond their number in any of the previous 
seventeen years.” 
Mr. Sprague is a spelling reformer, and a friend of Mr. H. 
Pitman ; consequently the orthography of his pamphlet reminds 
us of our old acquaintance the “ Fonetic Nuz.” 
Dynamics , or Theoretical Mechanics. In accordance with the 
Syllabus of the Science and Art Department. By J. T. 
Bottomley, Lecturer and Demonstrator in Natural Philo- 
sophy in the University of Glasgow. London and Glasgow : 
W. Collins, Sons, and Co. 
This book belongs to “ Collins’s Elementary Science Series,” and 
is specially prepared to meet the requirements of Science Classes 
under the “ Science and Art Department.” In the Introduction 
the author refers to a late change in nomenclature. “ The name 
Mechanics ,” he remarks, “ which properly denotes the science of 
machines, and was used by Newton in that sense, came for a 
time into use, instead of the appropriate word Dynamics , for the 
science which treats of force, and under that name — i.e., Me- 
chanics — there was a peculiar cross-division of the subject into 
Statics and Dynamics, in which the proper signification of the 
latter name was altogether departed from.” We fear there is, in 
the present day, too strong a tendency to abolish names, inap- 
propriate, indeed, if we look to their derivation, but which are 
thoroughly understood in favour of such as are more “ significant” 
and etymologically more correct. It is a singular fact that the 
terms “ mechanical ” and “ dynamical,” now regarded as syno- 
nymous, were at one time treated as decidedly antithetical. 
The work before us is divided into eight chapters, treating of 
the measurement of time, space, mass, velocity, acceleration, and 
