Marcu 14, 1912] 
eighth International Congress held at Gratz in 
August, 1910. The paper has lately been published 
‘at Jena in pamphlet form by Mr. Gustav Fischer. 
The subject is divided into two sections, one dealing 
with the physical conditions of the inundation-area 
and its relations to the periodical oscillations in the 
water-level of the Danube generally, and the other 
with the life of different portions of this area and its 
variation according to the different water-levels of the 
river. Of particular interest is the author’s description 
of the various means by which the fauna and flora 
accommodate themselves to the varying levels of the 
water, but, for reasons of space, these cannot receive 
detailed notice. A high water-level in the inundation- 
area is the delight of the fishermen, as will be evident 
from the statement that whereas in 1904, when the 
water-level only reached the 3°50 m. mark, and there 
was no overflowing of the banks, the catch of fish was 
920,000 kg., in 1907, when the water rose to 5°40 m., 
and the banks were overflowed for 128 days, the 
product was no less than 6,447,000 kg. This abund- 
ance of fish during big inundations is, however, only 
a part of a general phenomenon, the water-organisms 
at such seasons attaining a preponderating develop- 
ment at the expense of the land fauna and flora. 
Part tv. of the ‘Selected Reports from the Scien- 
tific and Technical Department of the Imperial Insti- 
tute ’’ (Cd. 6022, 1912) is devoted to rubber and gutta- 
percha. It relates chiefly to the composition and 
quality of rubbers prepared in different ways, and 
obtained from trees and plants grown under various 
climatic conditions in a number of British colonies. 
The trees and plants in question include not only 
well-known kinds such as Hevea, Funtumia, and 
Castilloa, but others less well known which may 
prove to be of value where the cultivation of the 
more important rubber-producers is not possible. 
The reports show the chemical composition of the 
samples submitted, and in many cases indicate the 
technical valuation also. In several instances the 
differences produced in the quality of the rubber by 
different methods of coagulating the latex are pointed 
out. Much work has been done by the department 
in studying the problems of coagulation, “curing,” 
and “‘tackiness’’ in rubber, but the conclusions are 
withheld for the present, pending confirmation by 
further experiments now in progress. A few speci- 
mens of gutta-percha from the Straits Settlements 
and other districts, and of balata from British 
Guiana and Venezuela, are described. Attention is 
directed to the question of utilising Para rubber seed, 
enormous quantities of which are now becoming 
available through the maturing of large plantations. 
The seed yields about 20 per cent. of oil, which is of 
commercial value as a substitute for linseed oil, and 
the residual cake may be of use for feeding cattle; 
some preliminary trials of it have given promising 
results, but require to be supplemented by experi- 
ments on a larger scale. 
Ar the meeting of the Mathematical Section of the 
Vienna Academy on February 8, Prof. J. Hann sub- 
mitted an important work entitled ‘‘The Diurnal 
NATURE 41 
Nevis.” The wind-force observations had not been 
discussed before; to a great extent only estimates of 
the hourly values could be given in the valuable pub- 
lished tables, as rime and snow-drift frequently inter- 
rupted the record of the anemometer. Dr. Hann care- 
fully investigated the relations between the estimated 
and registered values during fifteen summer months, 
and found corrections applicable to the values at 
different parts of the day; afterwards he subjected 
the estimated monthly means to harmonic analysis. 
The maximum wind-force at Ben Nevis occurs with 
extraordinary regularity between rh. and 2h. a.m. in 
all months. The minimum occurs at 4h. p.m. from 
November to March; at 5h. p.m. from April to June; 
at 3h. p.m. from July to October. The diurnal 
variation, even in winter, is well marked, with a large 
amplitude; at this season the difference of the daily 
extremes amounts to 105 m.p.s., and in summer to 
155. The smaliest values occur in spring and 
autumn. Storm frequency shows a regular daily 
variation in both half-years, with two maxima and 
two minima; in winter the maxima occur at 2h. and 
gh. a.m., and the minima at 6h. a.m. and 3h. p.m. 
In summer the daily period agrees completely with 
that of air-pressure : maxima, gh. a.m. and oh. p.m.; 
minima, 4h. a.m. and 3h. p.m. In the yearly mean 
this agreement still holds, with the trifling exception 
that the second maximum occurs at midnight. This 
double daily period of storm frequency is a very 
singular phenomenon; it is also shown at Vienna 
and other places. 
Tue photometric equipment of the laboratory of 
the Holophane Company of Newark, Ohio, is de- 
scribed and illustrated in the February number of 
The Illuminating Engineer of New York. The photo- 
meter is of the Dibdin radial type, the standard lamp 
moving on horizontal rails, while the lamp to be 
tested moves up and down a vertical shaft extending 
through three stories of the building. The photo- 
meter screen is maintained by two rods at a fixed 
distance from the lamp under test, and bisects the 
angle between the rays coming from the two sources. 
Arrangements are provided which allow the lamp 
under test and its reflector to be rotated either 
together or independently of each other. The 
Lummer-Brodhun contrast photometer screen is used, 
and in addition rotating sectors are provided which 
cut down the light on either side to a known fraction 
of its original amount. For direct-current tests the 
current is supplied by storage cells, and for alter- 
nating currents a small motor generator is run from 
the cells. 
Communication No. 124 from the Physical Labora- 
tory of the University of Leyden contains a short 
paper on the magnetic properties of solid oxygen, 
glass, and anhydrous ferrous sulphate at low tem- 
peratures down to 14° on the absolute scale, by Prof. 
Onnes and Dr. Perrier. In each case the suscepti- 
bility increases rapidly as the temperature falls, but 
appears in the case of oxygen and ferrous sulphate 
to reach a maximum at about 20° absolute. In the 
case of oxygen, the susceptibility increases fourfold 
on liquefaction. The deviations from Curie’s law are 
Variations of Wind-force on the Summit of Ben ! considerable throughout. A second paper in the same 
NO. 2211, VOL. 89] 
