412 
The same number of this journal has a note by 
_.A. P. Waldock upon the ‘“‘akund”’ fibre, obtained 
from the shrubs Calatvopis gigantea and C. procera, 
which the writer considers may have industrial 
possibilities as a village industry. In Industrial 
India, vol. i. No. 12, the possibilities are discussed 
of the ‘‘roselle’’ fibre, obtained from the bark of 
Hibiscus Sadariffa, particularly var. Altissima, which 
is said to have given good yields of fibre in Malaya, 
in regions with rainfall between 90 and 120 inches. 
For dry tropical regions there is “‘ sisal,’’ the fibre 
from the leaf of Agave vigida, var. sisalana. In 
Tropical Life for January Major L. A. Notcutt 
begins an interesting discussion of the possibilities 
of the cultivation and extraction of sisal, more 
particularly with reference to the problem whether 
the East African product may hope to compete 
with the Mexican in cost of production. At present 
our knowledge with all these fibre plants as to what 
conditions in cultivation favour maximum fibre 
development in the plant is entirely empirical, but 
such recent researches as those of Dr. W. L. Balls 
and H. A. Hancock (Proc. Roy. Soc., 93 B, 426-439, 
1922) upon the growth of the cotton hair, and the 
numerous investigations upon cotton and flax, now 
being published in the Journal of the Textile Institute, 
arouse hopes that we may soon have a deeper insight 
into the problem of wall formation and thickening 
in the plant, and this should prove the first step 
towards the control of cultivation with the view of 
facilitating the formation of fibre. 
FORAMINIFERAL SANDS IN Corsica.—Messrs. E. 
Heron-Allen and A. Earland (Bull. Soc. Sci. hist. et 
nat. de la Corse, 1922, p. 100, Bastia) find that the 
red sands of the Gulf of Ajaccio, which were supposed 
to owe their colour to derivation from adjacent 
granite rocks, are in reality largely composed of 
foraminifera. Some ten per cent. of their volume is 
composed of the rose-pink Polytrema miniaceum, a 
species havinga wide distribution in the Mediterranean, 
with which Mr. Heron-Allen was concerned in his 
recent report for the Zerra Nova expedition. The 
authors, in an inserted fly-sheet, show that they have 
much cause to complain (as was remarked in the 
famous “‘ Printers’ Bible’’) that printers have 
persecuted them without cause. 
DEPOSITION OF SILICA IN SEDIMENTARY ROCKS.— 
In such cases as the famous Devonian cherts of 
Rhynie, or the silicified forest of Arizona, geologists 
have urged the probability of an invasion of silica in 
solution from volcanic magmas. In suitable climatic 
conditions, however, much silica must be set free 
during laterising processes, and this may wander far 
from its original source. In the Proceedings of the 
Rhodesia Scientific Association, vol. 20, p. 9, 1922, 
Mr. H. B. Manfe records the interesting case of the 
silicification of a fairly recent freshwater shale at the 
base of the Kalahari Sands at Gwampa. Mr. T. B. 
Lawler of Princeton University (Amer. Journ. Sci., 
vol. 205, p. 160, 1923) describes the sheets of chalcetory 
that traverse the Oligocene strata of S. Dakota, 
passing alike through the sands and the included 
fossils. He attributes the vertical cracks in which 
they have been deposited to the squeezing out of 
water during the settling down of the beds, as the 
humid conditions of Oligocene times in the Dakota 
area were succeeded by an arid climate in the Miocene 
period. 
EARTHQUAKE PERIODICITY AND TIDAL STRESSES.— 
Recent numbers of the Bulletin of the Seismological 
Society of America (vol. 12, 1922, pp. 49-198) contain 
a memoir by Mr. Leo A. Cotton on earthquake 
periodicity with special reference to tidal stresses 
in the lithosphere. A welcome feature is the 
NO. 2786, VOL. I11] 

NATURE 

[MarcH 24, 1923 
sympathetic examination of Perrey’s neglected laws 
(of greater frequency about the syzygies, perigee, 
and the lunar passages of the meridian); the author 
considers that the first and second are supported by 
a high degree of probability, while the third is un- 
sound. The second part of the memoir deals with 
the effects of tidal stresses in the earth’s crust, with 
special reference to the geological aspects of the 
subject, such as the position of the originating 
faults. The author considers 316 world-shaking 
earthquakes from 1899 to 1903, and shows that 
earthquakes are more frequent when the sun or 
moon is near the horizon, and that there is a very 
high maximum of frequency when the sun and moon 
are so situated that they exert their tidal stresses 
in the same direction. 
METEOROLOGY AT LivERPOOL.—Results deduced 
from the meteorological observations taken at the 
Liverpool Observatory, Bidston, in the years 1920 
and 1921, have recently been published by the 
Mersey Docks and Harbour Board. The report and 
discussion was prepared by Mr. W. E. Plummer, 
director of the observatory. Observations are sup- 
plied three times daily to the Meteorological Office, 
which also receives monthly and annual returns. 
Daily results are given for the two years and the total 
and means are grouped for each month and each 
year. For 1920 the mean atmospheric pressure was 
29°942 in. (printed in error as 29°924 in.) ; the mean 
was above 30 in. in 5 months. The mean air tem- 
perature was 49°6° F., which is 05° F. above the 
normal, the absolute maximum was 78° F. and the 
minimum 21°F. The total rainfall was 33°34 in., which 
is 4°82 in. more than the normal; the duration of 
sunshine was 1257 hours, which is 222 hours less than 
the normal. For 1921 the mean barometric pressure 
Was 30°045 in., which is more than a tenth of an inch 
higher than in 1920; in a similar report for Southport 
especial mention was made of the exceptionally high 
barometric pressure which characterised 1921. The 
mean at Liverpool was above 30 in. in 7 months. 
The mean air temperature was 51° F., which is 1'9° F. 
above the normal ; the absolute maximum was 86° F. 
and the minimum 28°F. The total rainfall was 
22°47 in., which is 5°95 in. less than the normal ; 
the duration of sunshine was 1585 hours, which is 
99 hours more than the normal. The general modifi- 
cation of scales for the several elements which is 
being uniformly adopted by the Meteorological Office 
is not as yet being followed at the Liverpool Ob- 
servatory. ; 
THE SCATTERING oF Licur By Ligurps.—When a 
beam of ordinary light passes through a liquid its 
intensity gradually diminishes according to the ex- 
ponential law owing to the scattering of the light by 
the molecules of the liquid. The light scattered in 
a direction transverse to the beam should be com- 
pletely polarised. According to a paper in the March 
issue of the Philosophical Magazine, Prof. C. V. Raman 
and Mr. Rao have examined nine liquids to deter- 
mine to what extent the theories of scattering are in 
agreement with the facts, and find that the Einstein- 
Smoluchowski theory is the most satisfactory. Accord- 
ing to it the scattering should be proportional to 
the compressibility and absolute temperature of the 
liquid and inversely proportional to the fourth power 
of the wave-length of the light used. They find that 
the transverse light is only partially polarised, but, 
on applying the correction specified by Cabannes, 
which is due to the non-symmetrical molecules, the 
theory gives correctly the amount of the scattering. 
As the critical temperature of the liquid is approached, 
the scattering becomes very large and the polarisation 
of the scattered light more complete. 
eer 
3 
ae 
t= 
oasg 
a a RR 
Ra 
