1882.] 
Analyses of Books . 
363 
A similar complaint must be made concerning the gum-kauri 
of New Zealand, as the trees are being extirpated. It is esti- 
mated that half a century will see their practical extinction, and 
the local government, with true English disregard of the future, 
takes no steps for their protection or propagation. 
The article on silk is very important. It is unsatisfactory to 
find that India only produces one million pounds, as against 
six and a quarter millions from Italy and eight millions from 
China. Much may be hoped from the efforts made in Australia, 
but amidst many advantages there is in that group of colonies 
one important obstacle — the drying winds from the interior. In 
America the silk culture will meet with an impediment in the 
“ norther” from which, probably, no part to the east of the 
Rocky Mountains is quite free. 
In the treatise on soap it is much to be regretted that the 
strengths of solutions should have been expressed in Baume’s 
scale, which can scarcely be said to have a point in its favour. 
Notwithstanding some few defects, scarcely to be avoided in a 
work dealing with such a range of subjects, Messers. Spon’s 
Encyclopaedia will not for a long time be superseded. The trade 
statistics introduced under almost every section, showing the 
extent of the exports or imports, and the average London prices, 
will be a great convenience to the commercial world. The 
manufacturing articles give an excellent idea of the processes 
now in operation, and readers of an inventive turn will often find 
their attention called to some desideratum offering a good scope 
for their ingenuity. We can only express a confident hope that 
the work will be highly and duly appreciated by the public. 
British ' Fresh-Water Algae, exclusive of the Desmidice and 
Diatomacecz. With coloured plates by M. C. Cooke, M.A., 
LL.D., A.L.S. Part I. Palmellaceae, pp. 28, 11 plates. 
Part II. Protococcaceas and Volvocineas, pp. 45, 16 plates. 
London : Williams and Norgate. 1882. 
The best text-book on this subject, “ HassalPs Fresh-Water 
Algae,” published in 1845, is now extremely scarce, and much of 
the information therein contained quite out of date, owing to the 
numerous discoveries made during a period of more than thirty- 
five years, most of which are scattered through the pages of 
numerous scientific periodicals. Under these circumstances, 
the issue of a new work on the subject cannot but prove accept- 
able to an increasingly large class of readers, who, thanks to the 
Royal Microscopical and other kindred societies, of which it is 
the parent, have been taught to study natural science for its own 
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