BOOK RECEIVED—A COURSE OF PRACTICAL CHEMISTRY. 203 
the Alpine plants of the United States are related specifically to the 
flora of Labrador—depends evidently, (unless we adopt the theory of 
centres of creation) on a southern migration of these forms during the 
gradual development of this period of cold, and on their subsequent 
destruction in intervening districts, as the glacial forces slowly 
dwindled back to within their present limits. It must not be for- 
gotten, moreover, that the results of glacial disturbance, were appa- 
rently confined to northern and extreme southern latitudes, in place 
of being of universal manifestation. Within the tropics for example, 
our true Drift deposits—the accumulations of glacial agencies on sub- 
merged areas—are properly unknown. This fact alone, consequently, 
points to a very different condition of things from that indicated by 
the language of the sacred record. Nor can the comparatively modern 
uprise of large areas in South America and elsewhere, help to sustain 
our author’s opinion ; because these elevated tracts are the results of 
forces really still in action, and afford nowhere the slightest indica- 
tion of the former existence of one grand and vast convulsion affect- 
ing equally the whole globe. 
We need not carry our analysis farther; but it would be easy to 
shew that if we took the close of any geological period as our starting 
point—so far as it is possible to determine this—equal difficulties 
would beset the literal interpretation of the Mosaic day. But truly 
—and the fact becomes more and more apparent as work after work, 
like that now under notice, becomes added to our stock—human 
Science as yet is all too unprepared to undertake the investigation of 
these grave and apparently impenetrable mysteries. Whilst thus 
compelled, however, to dissent from the views of our author, as ex- 
pressed in this portion of his work, we may fairly add our testimony 
to the general value of the work itself. As a treatise of undoubted 
merit, and as a home product both of pen and press, it well deserves 
the attention of all interested in the progress of Canadian literature. 
E. J. C. 
Book REcEIvED:—A Course of Practical Chemistry. By Henry 
Croft, F.C.S., ete. Toronto: Maclear and Co, 1860. 
Want of space compels us to postpone our notice of Professor 
Croft’s useful Handbook of Analytical Chemistry, just published by 
Maclear and Co, until the next issue of the Journal; but, in the 
mean time, we may recommend it as being especially adapted to the 
requirements of our Medical and University students. 
