146 
NATURE 
[DECEMBER 17, 1903 
| 
trusion of solid masses and other phenomena con- | Arizona was caused, it was suggested, by the impact 
nected with stratigraphical structure. 
Here we have only just arrived at the end of the 
first volume of the present issue. The second volume 
begins in the middle of Book IV., with a continuation | 
of the description of the manner in which the earth’s 
crust has been built up and modified. This second 
part, however, refers to the action of internal heat and 
pressure, that is to say, it deals with rocks of igneous 
origin, whether superficial or deep-seated, and this 
leads to the consideration of earth movements, without 
which we should be unable to examine such rocks at 
all. Incidentally he here describes the mode of forma- 
tion of veins and lodes. 
Book V. gives a series of very much condensed, but 
still very useful notes on fossils and their place and 
use in geological investigations. This might be greatly 
extended. 
Then follows in Book vi. 
stratigraphy. 
Our author arranges the stratified rocks under 
fifteen heads, and treats of their general characters, 
their flora and fauna, and their local development at 
home and abroad; but this, again, our author could 
easily develop into at least five volumes, representing 
the five groups under which the whole of historical 
geology could be very conveniently arranged. 
In the seventh and last book he deals with the geo- 
graphical features of the earth’s surface, as affected 
by its geological character, and the arrangement of 
the materials of which it is composed. 
There are buried in this text-book an immense 
number of facts vastly interesting to the general 
reader, and especially to the traveller ,who goes about 
with his eyes open, but without knowledge to follow 
the processes by which nature brings about the 
wonderful results observed. For instance, how seldom 
he realises when he sees the great blocks of travertine, 
so commonly used for building in Rome, that this lapis 
Tiburtinus, modified by Italian lips into travertino, is 
not a rock built up by the same kind of sediment as 
that of which most of the building stones he has seen 
elsewhere are composed, but that it is carbonate of 
lime which has been thrown down from chemical solu- 
tion, and that plants have helped to collect it, while 
another similar rock, as commonly used elsewhere, has 
been collected by small animals, particle by particle, 
out of the sea water in which it was dissolved. Or if he 
is looking at those marvellous relics of volcanic activity, 
the geysers, which heap up silica instead of carbonate 
of lime, he will find that there also a small confervoid 
alga helps to collect the pasty material which after- 
wards hardens into flint. These are examples of scien- 
tific facts which would not force themselves upon the 
observation of the ordinary tourist, but which it would 
greatly add to his enjoyment of travel to know. Or, to 
take another more abstruse example, the study of the 
earth’s satellite has suggested that the scars and pits 
upon it are due to the impact of aggregations of 
matter, and a similar bold hypothesis has been offered 
in explanation of certain depressions upon the earth. 
A basin-like hollow among the sandy mounds of 
NO. 1781, VOL. 69] 
the whole of systematic 
| of a meteoric body now possibly buried out of sight 
below, while the basin of the Atlantic, according to 
others, marks the area from which the material of the 
moon broke away from its moorings and commenced 
its long spiral spin round the earth. Such flights of 
imagination have often given us working hypotheses, 
which after pruning and shaping have found a place 
among the explanations of the order of the world. 
While we welcome all such tentative interpretations 
of phenomena, we must carefully weigh the evidence 
adduced, and not too hastily say proven or not proven. 
The work is encyclopedic in character and arrange- 
ment, and, but that, alas! the question of cost has to 
be taken into consideration, we should gladly welcome 
its appearance in a dozen or more goodly volumes, the 
contents of which would be suggested by its present 
division into Books, some of which, as we have sug- 
gested, might be expanded into more than one volume. 
Then we might ask for larger type, instead of as now, 
800 words to a page, and also for many more of the 
author’s own clever sketches, and more illustrations 
such as those he has so judiciously selected from other 
sources. 
NEW TEXT-BOOKS OF GEOMETRY. 
Practical Plane and Solid Geometry. By I. H. Morris 
and J. Husband. Pp. viii+254. (London: Long- 
mans, Green and Co., 1903.) 
First Stage Practical Plane and Solid Geometry. By 
G. F. Burn. Pp. viii + 240. (London: W. B. 
Clive, University Tutorial Press, Ltd., 1903.) | 
Price 2s. 
Examples in Practical Geometry and Mensuration. 
By J. W. Marshall, M.A., and C. O. Tuckey, M.A. 
Pp. xii +70. (London: George Bell and Sons, 
1903.) 
Elementary Geometry. Section ii. By Frank R- 
Barrell, M.A., B.Sc. Pp. viiit+t169 to 284._ | 
(London: Longmans, Green and Co., 1903.) Price | 
Is. 6d. \ 
Theoretical Geometry for Beginners. Part ii. By 
C. H. Allcock. Pp. viii + 123. (London: Mac- | 
millan and Co., Ltd., 1903.) Price 1s. 6d. { 
Notes on Analytical Geometry. By A. Clement Jones. 
Pp. iv+172. (Oxford: Clarendon Press, 1903.) 
Price 6s, net. 
Elementary Graphs. By W. M. Baker, M.A., and 
A. A. Bourne, M.A. Pp. iv+34. (London: George — 
Bell and Sons, 1903.) Price 6d. net. 
EXT-BOOKS in this country which deal with the 
practical applications of geometry naturally 
follow the South Kensington division of the Board of - 
Education, a department of the public service which . 
has always taken a leading part in the spread of this 
branch of knowledge. The department has two distinct 
syllabuses, one for the guidance of art classes, the other 
for science. Both syllabuses have quite recently been , 
revised and considerably extended, and are well abreast 
of the times. Although the two schemes have parts 
in common, there is an increasing tendency for them 
