429 
1883 .] Analyses of Books . 
Professor Marsh seems of the same opinion. On the other hand, 
C. Drayton Gibbes writes : — “ Many frontiersmen of great experi- 
ence in tracking Indians, and also bears and other wild animals, 
have witnessed these footprints, and all give their judgment 
without a question in favour of their human origin.” Dr. Hark- 
ness expresses himself also as satisfied that the tracks are those 
of men. He remarks, very acutely, that if the impressions were 
those of any unshod animal, be it mammalian, biped, quadruped, 
or bird, they might differ in size, but would all be of the same 
pattern, which is not the case. Such a difference in shape be- 
comes, however, quite intelligible if we suppose the footprints 
made by men wearing rudely-fashioned sandals. 
The Students' Mechanics. An Introduction to the Study of 
Force and Motion. By Walter R. Browne, M.A. 
London : C. Griffin and Co. 
The work before us, although especially designed for the use of 
students, has the valuable peculiarity of being non-examinational. 
The author, in his preface, remarks that the successful prosecu- 
tion of Mechanics, especially as applied to practical construction, 
chiefly depends on the obtaining a clear and thorough mastery 
of a few leading principles, such as the composition of forces, the 
principle of moments, and the doctrine of energy, which are 
necessary for the solution of almost all the problems of ordinary 
practice. He takes occasion to add that whilst it is “ easy to 
learn such propositions sufficiently for the purposes of an ex- 
amination, it is by no means easy to know and understand them 
so thoroughly as to be able to use them freely and confidently in 
attacking questions of practical importance.” His object is to 
assist the student in attaining such a true practical knowledge. 
He therefore brings forward the doctrine of central forces and 
the conception of energy at the very outset. We are bound to 
admit that his treatment of the subject is happy, and that 
students of fair intelligence, and desirous of gaining a genuine 
mastery of mechanical science, will find here what they require 
for their guidance. 
