300 
NATURE 
[JuLY 27, 1899 
impress. In all countries where Europeans have settled, we find 
they have altered in temperament, ideas, and bodily features. 
The change is slow at first, because fresh blood constantly 
streams in from the mother country and perpetuates the origina] 
characters ; but as the Colony grows older the immigration 
falls off, and the new settlers diverge further and further from 
the original type. We have no reason to dread this evolution ; 
it is the outcome of adaptation; and when we consider the 
splendid physical characteristics of many of the native races 
which inhabit tropical regions, we may fairly conclude that 
such adaptation will lead to the development of new types no 
whit inferior to the old. When we further consider that man, 
modifying the environment and substituting his selection for 
that of nature, has been able to produce and to develop endless 
varieties of domestic animals which would never have come into 
existence under natural conditions, and would soon deteriorate 
or perish when out of their artificial surroundings, we may cer- 
tainly believe that he can, by taking thought, escape many of 
those detrimental influences which irresistibly modify all other 
organic beings.” 
“THE Geology of the Coolgardie Goldfield” forms the sub- 
ject of the third Bzzlletin of the Geological Survey of Western 
Australia, and it is written by Mr. Torrington Blatchford, 
Assistant Government Geologist. This goldfield was discovered 
in 1892, and in the course of six years over two thousand tons 
of ore have been crushed, yielding gold at the rate of 1 oz. 
3 dwt. per ton. This has been derived mainly from quartz 
reefs and partly from ‘‘lode formations.” The amount of gold 
obtained from the rich alluvial deposits has not been estimated. 
The district of Coolgardie consists of a mass of granite on the 
west, succeeded by a belt of hornblendic and talcose schists, 
the whole being intersected by igneous dykes. Recent super- 
ficial deposits cover a large portion of the field, and at the 
base of these there is in places a thin stratum of ‘‘ cement,” 
an auriferous conglomerate that has not yet proved of much 
economic value. Gold is found in pyrites in the altered schists 
bordering the acid dykes, and the material is traversed by 
numerous small quartz leaders forming ‘‘stockworks.” Though 
much gold has been won from this source, the lodes are small 
and irregular. The quartz reefs occur principally in the schists, 
and they dip from 60° to 80° to the east. The water-supply 
of the region is a source of trouble and expense. With a rain- 
fall of only seven inches no great supply can be expected, except 
by storing. Shallow wells yield limited supplies up to 4000 
gallons per diem at a depth of 200 feet, but a good deal of the 
underground water is saline. Deep boring has been unsuccess- 
ful, and supplies have in some cases to be brought from a dis- 
tance. An excellent coloured geological map, on a scale of an 
inch to forty chains, has been prepared by Mr. Blatchford and 
Mr. E. L. Allhusen. This is an index to a larger map which 
is published separately. 
In the Ph2losophical Magazine for July the Rev. O. Fisher 
eals with the residual effect of a former glacial epoch upon 
underground temperatures. The object of the paper is to 
examine whether traces of the effects left by a former glacial 
period upon underground temperatures are sufficient in amount 
to enable estimates to be made, from observations in deep 
wells and mines, of the lapse of time since the ice disappeared 
from the land. The author investigates the character of the 
traces which a former glaciation might be expected to leave 
behind, the principal one being a reduction of the gradient. 
From observations of the temperature of a well at Wheeling, 
U.S.A., combined with a certain assumption, the author esti- 
mates the time of the glacial period at 34,013 years. On the 
whole, however, he considers that the question as to whether 
there is any prospect of estimating the date of the glacial epoch 
NO. 1552, VOL. 60] 
from underground temperatures must be answered in the nega- 
live ;) nevertheless, the different gradients observed in different 
localities may possibly be attributable in a measure to glaciation. 
In No. 8 of the series of Frammenti concernanté la geofisica 
(Rome) Dr. Folgheraiter gives an interesting account of the 
singular magnetic effects produced by lightning on a house at 
Torre Nuova, which was struck on April 8 last. The obsery- 
ations led the author to conclude (1) that the lightning produced 
a large number of singular points and zones in the masonry, it 
being inadmissible that the individual stones should have been 
so highly magnetised before construction of the walls ; (2) that 
while doubts have hitherto existed as to the possible form- 
ation of singular points in tufa, this question has now been 
answered in the affirmative ; (3) the alternation in the polarities 
of the singular points and zones, even on the same piece ef tufa, 
is noteworthy, but no connection has yet been established be- 
tween these alternations and the mode of propagation of the 
electricity ; (4) it is now amply proved that lightning produces 
marked magnetisation independently of the inductive action of 
terrestrial magnetism, 
WE have received a paper by the Rey. F. S. Chevalier, S.J., 
published by the Zi-ka-Wei Observatory, on the navigation of 
the Upper Yang-tze. The author’s knowledge of the river is 
chiefly derived from personal observation made during a voyage 
as far up as Ping-shan-hsien during the winter of 1897-98. He 
takes a much more hopeful view of the navigability of the Upper 
Yang-tze than did Lieut. Dawson, whose survey is reported 
onin the China Sea Directory. The three chief obstacles, in 
the form of rapids, are discussed in detail, and suggestions are 
made with the view of making their navigation practicable. 
M. Chevalier has in preparation a chart of the river from 
I-chang to his highest point, on a scale of 1/25,000. 
Tue debatable question of the diffraction of Rontgen rays 
forms the subject of some recent experiments described by Prof. 
H. Haga and Dr. C. H. Wind in the Proceedings of the Royal 
Academy of Sciences of Amsterdam. In such experiments it is 
better, in order to obtain greater intensity, to use narrow slits 
than to make the distances great. As the time of exposure 
varied from 29 to 200 hours, the apparatus had to be mounted 
on a heavy freestone block supported on the central pillar of 
the Physical Laboratory of the University of Groningen, where 
the experiments were made. The diffraction slit was 3 cm. 
high and 14 microns at the upper end, gradually narrowing to a 
width of a few microns. A careful examination shows a kind of 
broadening out of the image corresponding to the narrowing 
of the slit, and this it is considered can only be attributed to 
diffraction of the Rontgen rays. The authors give estimates of 
the wave-lengths of the rays lying between 0,12 and 2,7 
Angstrom units, but consider that they cannot succeed in 
making meastirements instead of estimations of the wave-length 
until Rontgen tubes have been produced remaining in working 
order as long as those used, and giving out rays of much greater 
energy. 
THOSE responsible for the ‘‘ Guide to the Museum of Eton 
College,” seem remarkably fond of displaying an acquaintance 
with technical terms. Why, for instance, in giving a list of the 
birds of Berkshire, was it necessary to encumber it with the 
subheadings ‘‘ Neornithes,” and ‘‘ Carinate,” seeing that all 
existing birds come under the former category, and all those 
of Europe under the latter ? 
duced, and the language somewhat simplified throughout, the 
Guide would be admirable for its purpose. The museum appears 
to be well arranged ; and itis satisfactory to note that the authori- 
ties recognise the importance of making the local collection the 
most prominent feature. 
If the number of names were re- 
