498 Reviews. [Oct., 
Writing at a time when chemistry is verging on a new phase, 
Dana very prudently effects a compromise between the new and 
the old theories by writing his formule in accordance with both. 
Another improvement in the present edition is the systematic recog- 
nition of the varieties of each species. 
Although Professor Brush’s name appears on the title-page 
of this edition, it would seem that his labours relate only to the 
pyrognostic characters of the minerals described. “ Neither the 
consultation of original authorities, the drawing of conclusions, nor 
the putting of the results on paper, has been delegated to another. 
And being now,” continues the author, “but half-way between the 
fifties and sixties, it is my hope that the future will afford another 
opportunity for similar work.” In this hope, every mineralogist 
will heartily concur. 
ENGINEERING WORKS. 
A TREATISE on ‘Coast Defence, by Von Scheliha, Lieutenant- 
Colonel and Chief Engineer of the department of the Gulf of 
Mexico, of the army of the late Confederate States of America,* 
deserves more than a passing notice, containing as it does a very 
comprehensive account of the means for the attack and defence of 
coasts, as practised in modern warfare, backed by the experience 
gained during the late American war. Thus it forms a very valu- 
able addition to works on Military Engineering, and will doubtless 
be found a useful text-book for the study of naval and military 
officers. 
It will readily be admitted that the progress made in naval 
architecture, and in artillery, necessitates some modification of the 
principles heretofore observed in coast-defence. The increased 
power of the guns of the present day would knock to pieces any 
fort that was constructed twenty or even ten years ago, and the 
masonry walls of recent years must now give place to iron sheathing. 
Wherever practicable, a well-turfed earthen slope is, however, still 
a safe protection in many cases; but the recent invention of 
Lieutenant Moncrieff’s elevating gun-carriage will, if found prac- 
ticable in service, go far towards inverting the present practice of 
coast-defence, and pits will be dug for the guns instead of building 
forts; thus they would be entirely protected from all, except shells, 
and no doubt means will soon be devised for keeping them out 
also. In the work under our notice the advantages of railroad 
communication along the sea-shore are forcibly poimted out as a 
means whereby the scattering of forces by fortifying places of 
secondary importance may be avoided ; on this point there can be 
* London: E. & F. N. Spon, 1868. 
