626 
mathematics out of the attempts of mathematicians to 
improve the theory of parallels. A historical account is 
given of the development of the new geometry by Gauss, 
Lobatchewsky, Bolyai, Riemann and Beltrami. Con- 
siderable attention is given to the three prevailing 
misconceptions which have retarded the development of 
the subject, namely, the introduction of a fourth dimension 
in connection with the notion of curvature of space, the 
projective definitions of distance and angle, and the 
necessity for introducing rigid bodies in geometry. 
The writer of the article on evolution has had a difficult 
task, with which, on the whole, he has grappled success- 
fully. We miss, however, any clear presentment of the 
crucial point on which the controversies that at present 
divide evolutionists indisputably turn—viz. that of the 
transmission or otherwise of modifications due to 
individual plasticity. It seems inadequate to say, with- 
out explanation, that “the weakness of the neo- 
Lamarckian view lies in its interpretation of heredity,” 
when, as a matter of fact, the whole neo-Lamarckian 
fabric must fall unless the reality of such transmission 
can be established. The summaries given of several 
modern developments of evolutionary theory are scarcely 
full enough to be of much value to the specialist, while 
the unskilled but intelligent reader in search of informa- 
tion, whose requirements should always be kept in view 
in a work like the present, will, we fear, find their lan- 
guage often too technical to give him what he wants. 
The writer tells us that 
“multiradial apocentricities lie at the root of many of 
the phenomena that have been grouped under the 
designation of Convergence.” 
We should say rather that the first phrase merely 
repeats the idea of the second in a more cumbrous form. 
Moreover, we doubt whether anyone not an expert 
would grasp the meaning of either expression, or that of 
“homogeneous homoplasies,” without illustration. The 
account given of the recent departure in biometrics is 
good so far as it goes, and the position of its exponents 
is not unfairly stated ; justice, however, is hardly done 
to the fact that the quantitative stage is inevitable in any 
inquiry the material of which admits of measurement. 
Workers in this department are fully alive to the danger 
pointed out by Dr. Mitchell, and analysis of composite 
characters is making progress under the 
supplied by the rediscovery of Mendel. 
The article dealing with forests and forestry is in 
two parts, the general part by Dr. Schlich, C.1.E., 
F.R.S., and that referring to the United States of 
America by Mr. Gifford Pinchot, Forester of the U.S. 
Department of Agriculture. 
Dr. Schlich first deals with the general distribution of 
forests throughout the world, and this might with advan- 
tage be more detailed. His account of the utility of 
forests based on their indirect and direct advantages is 
admirable, the former being chiefly the prevention of the 
denudation of hill-sides and of the consequent flooding 
of low-land and the silting-up of river-beds. The direct 
utility of forests increases steadily with the population of 
civilised countries, and it is a remarkable proof of the 
effects of economic progress that whereas in 1880 Ger- 
many produced as much timber as she required, in 1899 
NO. 1721, VOL. 66] 
stimulus | 
NATURE 
| 
[OcroBER 23, 1902 
she imported 4,600,000 tons, valued at 14,000,000/7. and 
this in spite of the increasing yield-capacity of her State 
forests. The latter comprise about one-third of her 
forest area, but as continental communal forests are 
chiefly managed by the State, it is a pity that they are 
not separated from private forests in the table of areas, 
for continental private forests are frequently no better 
managed than our own. Eighty-seven per cent. of the 
timber we import yearly, worth about 22,000,000/., is 
coniferous, and it is chiefly on Canada, with 1,250,000 
square miles of forests, that the world will have to 
depend for the future. Curiously, the table showing 
movements of timber within the British Empire entirely 
omits Canada. 
Dr. Schlich appeals to the landowners of Britain to 
afforest 3,000,000 of our 24,000,000 acres of lands either 
waste or used for light hill grazing, and for more attention 
to forestry by our colonies, most of which are no better 
than Canada in this respect. He gives an interesting 
account of forest management in India, the managed 
State forests of which, comprising, in 1900, 95,000 square 
miles, 10 per cent. of the area of British India, yielded 
(18g0-95) an average net revenue, which is steadily in- 
creasing, of 73,70,000 rupees. Progress in forestry is 
also being made in South Africa and Ceylon. 
Mr. Pinchot gives a good summary and a map of the 
distribution of forests in the United States, the chief 
causes of destruction of which are over-lumbering and 
fires. He gives a map of the present State reserved 
forests, which, although amounting in area to 72,500 
square miles, look inconspicuous on the huge territory of 
3,500,000 square miles. He has also drawn up a useful 
history of the State protection of forests, which was 
greatly assisted by the large reservations carried out by 
President Cleveland and the forest law passed in 1897, 
the general purport of which he explains and praises. 
Forest education has progressed in America, forestry 
being taught at several universities and other insti- 
tutions. Mr. Pinchot states, however, that European 
forestry is not yet applicable to America, but that the pro- 
duction of a net revenue and the perpetuation of the forest 
are the chief objects of the private forest owner, who is 
the principal timber producer in the States. There is an 
account given of the lumber trade, and the ominous note 
occurs that numbers of the eastern white pine lumber- 
and mill- men have removed to the southern States and 
Pacific Coast, driven away by the exhaustion of their 
supplies. From Dr. Schlich we learn that already the 
United States imports from Canada nearly as much 
timber as it exports. 
The article “Geology” is written happily by the same 
authority, Sir Archibald Geikie, who contributed the 
elaborate essay in vol. x. of the ninth edition. He divides 
his subject as before into sections, and reviews inthe 
same lucid manner the general progress made during the 
interval. In its cosmical aspects, the record is not, how- 
ever, one wholly of progress, as Croll’s astronomical 
theory is no longer considered to afford a solution of the 
problem of the Ice age. Many have dealt with the 
question of the earth’s age, notably Sir A. Geikie, and we 
cannot wonder that he repeats his protest. against the 
time-restrictions of physicists and mathematicians. No 
evidence of progressive diminution of activity, whether of 
