436 

Mr. H. P. Cusuinc (American Journal of Science, 
vol. xxxix., p. 288) criticises the view of Prof. W. J- 
Miller that the syenites and granites of the Adirondack 
region belong to one vast intrusive body, and main- 
tains that here, as in Canada, there is an older group 
of orthogneisses which is intruded into the Grenville 
Series. This group has suffered severe regional meta- 
morphism, and has been invaded by later rocks of 
the anorthosite-syenite group. The older orthogneisses 
may therefore be styled Laurentian, as in Canada. 
Tue expedition of Mr. F. B. Loomis from Amherst 
College to Patagonia resulted in his discovery, pub- 
lished in 1914, that Pyrotherium was a proboscidean. 
He referred the beds in which it occurred to the 
Oligocene. Mr. Carlos Ameghino (‘Boletin de la 
Sociedad Physis,” vol. i., p. 446, Buenos Aires, 1914) 
states that certain white sandy clays underlying the 
Pyrotherium beds, and recognised by Loomis as Cre- 
taceous, are the strata that contain Notostylops, Noto- 
pithecus, and other mammals. _Ameghino accepts a 
Cretaceous age for these, and believes that Pyrotherium 
is an early Eocene form. If this were proved, the 
ancestry of the proboscideans is to be sought, as 
Ameghino urges, in S. America rather than in Africa. 
Tue paper entitled “The Microspectroscope in 
Mineralogy,” by Mr. Edgar T. Wherry, assistant 
curator of the division of mineralogy and petrology 
in the U.S. National Museum, which forms No. 5 of 
vol. Ixv. of the Smithsonian Miscellaneous Collection, 
constitutes an important contribution to our know- 
ledge of the absorptive properties of minerals. So 
long ago as 1866 Sir Arthur Church first noticed the 
existence of an absorption spectrum in zircon, but 
hitherto no systematic study has been made of the 
subject. Mr. Wherry has examined specimens of 
about two hundred minerals, and the results of his 
investigation are carefully tabulated. The analytical 
key given at the end of the paper should be invaluable 
to those making use of the method for determinative _ 
purposes. He found that better results were afforded 
by light diffused from the specimen than by light 
transmitted through it. The beautiful violet calcite 
from Joplin gives the neodymium absorption spec- 
trum, and so do the yellow sphene from Switzerland 
and the brown apatite from Ontario. It is unex- 
pected to learn that the colour of the violet-red alman- 
dine garnet is apparently due to vanadium. The 
presence of magnesium and manganese has no effect 
upon the colour of garnet. The bands shown by 
zircon are due to the presence of uranous uranium, 
usually in amounts of less than o’5 per cent. The 
resulting blue colour is often masked by the other 
agents, such as iron or manganese. Brown or white 
zircons do not show a spectrum. 
Symons’s Meteorological Magazine tor May gives 
the diurnal range of rainfall at Karlsruhe (Baden) 
and at Petrograd. The results have been ob- 
tained by Henrik Renqvist, Helsingfors, for the 
summer months June, July, and August from the 
published hourly values of rainfall. For Karlsruhe 
the observations dealt with are for twenty-two con- 
secutive years, from 1892 to 1913 inclusive. Per- 
NO. 2381, VOL. 95| 
NATURE 
[JUNE 17, 1915 

centages of the total fall are given for each interval 
of four hours. The highest percentage value is 22:0 
for 4 to 8 p.m., and the lowest 12-2 for 8 a.m. to 
noon. The results for Petrograd are for the twelve 
years 1897 to 1908, and have been dealt with in the 
same way. The highest percentage is 22-3 for noon 
to 4 p.m., and the lowest 13-3 for 4 to 8 a.m. Both 
stations are fair representatives of the Continental 
type, and show a maximum in the afternoon and a 
minimum in the morning. Karlsruhe is said to have 
a diurnal range of rainfall highly resembling that of 
Perpignan, for which the percentages are given. 
Petrograd shows great similarity to Kew, the results 
for which are given from ‘‘The Diurnal Range of 
Rain,”’ issued by the Meteorological Council. 
Tue Journal of Agricultural Research, iii., 5 (Wash- 
ington), is scarcely the place in which one would expect 
to find a paper on fitting logarithmic curves by the 
method of moments. The use of logarithmic curves 
would appear to be desirable for tabulating biological 
statistics, and the object of the paper is to determine 
the constants when the formula assumed is of the 
form of a quadratic function plus a logarithm. Mr. 
John Rice Miner determines these constants in terms 
of the area and first two or three moments of the 
curve, but unfortunately the formula are very labori- 
ous in the carrying out, and it would certainly appear 
desirable to simplify them. 
TuHE Journal of the Washington Academy of Sciences 
for May 19 contains a short account of a new calori- 
meter due to Messrs. H. C. Dickinson and N. S. 
Osborne, of the Bureau of Standards. The calori- 
metric substance is a block of copper in which are 
embedded a platinum resistance thermometer and a 
coil of resistance wire for supplying heat to the block 
electrically. A number of test experiments on the 
specific heat of water show that a degree of accuracy 
of 1 part in 2000 may be obtained with the calorimeter. 
The specific heat between — 40° C. and 0° C. and the 
latent of fusion of ice at 0° C. have also been deter- 
mined with the apparatus. The results for the specific 
heat are given by the expression 0:5057+0-001860, 
where @ is the temperature Centigrade, and for the 
latent heat 79-76 in terms of the gram-calorie at 20° C. 
The latter figure is in close agreement with the value 
79:74 previously obtained at the Bureau by other 
methods, so that it seems probable that the mean 79°75 
may be accepted as a close approximation to the true 
value of this important constant. 
M. Ernest Coustet contributes to La Nature of 
May 22 a useful article on the dosage of X-rays. He 
admits that the mere observation of the current 
traversing the X-ray tube is apt to be very misleading. 
Better results are given by comparing the fluorescence 
produced by the rays with the fluorescence produced 
by a radium bromide standard, This method implies 
a careful observation of the time of exposure, a neces- 
sity which is avoided by the various ‘‘ chromometers”’ 
devised by Holzknecht, Bordier, Sabouraud, and Noiré, 
| in which the dose is estimated by the coloration of 
| sodium chloride or bromide, or of barium platino- 
| cyanide. Since, however, the estimation of tints does 

