AprIL 28, 1923] 
The hydrogen-ion concentrations of some Indian 
soils and plant juices have been determined by 
W. R. G. Atkins (Bull. 136, Agricultural Research 
Institute, Pusa), who suggests that the method may 
be useful to agriculture in various ways, as, for 
example, to delimit the degrees of soil acidity or 
alkalinity within which it is possible to grow certain 
crops, and to determine the lime requirements of 
particular soils. The acidity of some sandy Assam 
soils is suggested as the cause of their high content 
of available phosphate, which is beneficial to indigo 
and other crops. The reaction even of highly cal- 
careous soils may be somewhat modified by manurial 
treatment, the use of such manures as sulphate of 
ammonia or potash rendering the soils slightly less 
_ alkaline, the reduction being about Py 0-4. A 
_ further reduction takes place in waterlogged soil, 
owing to the accumulation of carbonic acid. The 
value of gypsum on black alkali lands is attributed 
to the fact that calcium sulphate will, by precipita- 
tion of calcium carbonate, reduce the alkalinity of 
a sodium carbonate solution from P; 10-or less to 
P,, 8, the latter being a limit suitable for plant life, 
whereas the former is not. 

Fact and Phantasy in Industrial Science.} 
THE title of the lecture is intended to add to the 
obvious meaning of ‘industrial science”’ the 
complementary idea of a discipline or school of 
philosophy, and an interpretation under which the 
antithesis conveyed in the current expression “ pure 
and applied science ’’ is divested of any unreality. 
In regard to accumulation of exact knowledge of 
phenomena, no distinction of method or object is 
evident. “‘ Pure science,’ however, is ideal in a sense 
which seldom characterises industrial research or 
scientific development of production. 
The cellulose industries represent a vast accumula- 
tion of exact knowledge and a formidable array of 
statistical evaluation of fundamental matters of 
accepted fact. This tends to eliminate phantasy and 
imagination from the investigation of the primary 
routine processes of these industries, whereas these 
faculties have full play in the secondary arts of 
decorative treatment, e.g. in weaving design, bleaching 
and finishing, dyeing and printing : on the other hand, 
science has contributed new products, e.g. mercerised 
cottons, and the artificial (cellulose) silks, and 
attendant progressive extensions and developments, 
both artistic and scientific. Systematic scientific 
study of cotton, as an organic structure, as a colloidal 
complex with specifically characteristic hydration 
capacity, and as a chemical individual, is opening a 
vista of new developments of the primary textile 
industries. 
Moreover, industrial research in this section adopts 
the unit cotton hair, as the determining factor of the 
industry, which is a radical change of the basis of 
accepted fact, from the empirical to the scientific. 
Similarly in the papermaking industry, current 
research concerns itself with units of minute dimen- 
sions, and the phenomena of the unseen and sub- 
sensible order. © This trend of research again involves 
the faculties of phantasy and its more disciplined form 
of imagination. 
The future of creative or constructive development 
of the cellulose industry would appear to be bound 
up with the application of physical and biological 
method: the former in investigating the properties 
of cellulose as such, and its actions and reactions 
in relation to light, heat and electricity ; the latter 
1 Abstract of a discourse delivered at the Royal Institution on Friday, 
February 2, by Mr. C. F. Cross, F.R.S. f 
NO. 2791, VOL. t11] 


NATURE 
585 
in investigating the conditions of origin of cellulose 
structures, the natural history of bacterial resolu- 
tions, and the formation of humus, peat, lignite and 
coal. This general sketch of the matter of the lecture 
was developed by specimens and demonstrations. 

Depth of Earthquake Foci. 
‘THE question of the depth of earthquake foci is 
attracting considerable attention among seis- 
mologists, and forms the subject of several recent 
papers (Mon. Not. R.A.S., Geoph. Sup., vol. i., 1923, 
pp. 15-22, 22-31, and 50-55). In the first of these 
Dr. Dorothy Wrinch and Dr. H. Jeffreys consider 
the seismic waves from the Oppau explosion of 
September 21, 1921, which were registered at five 
observatories on the Continent at distances ranging 
from 110 to 365 km. from Oppau. Using the method 
of least squares, they find that the velocities of the 
P and S waves (first and second preliminary tremors) 
are respectively 5-4 and 3:15 km. per sec. These 
values, which are of course those for the superficial 
sedimentary layer, are much less than those deter- 
mined from observations of earthquake waves (7-1 
and 4:0 km. per sec.) for the upper layers. 
A more important earthquake with a superficial 
origin is the Pamir earthquake of February 18, 1911, 
which, as Prince Galitzin suggested and Dr. Jeffreys 
has shown, was the result of the fall of a great 
landslip. This earthquake was recorded at seis- 
mological stations all over the world. Dr. Jeffreys 
compares the times of arrival of the P and S waves 
at various distances from the origin with those given 
by the standard tables. The latter represent the 
average of a large number of earthquakes, the foci 
oi which were situated at various, though unknown, 
depths, but none of which was on the surface. Now, 
if the latter depths were great, as suggested by the 
late Dr. G. W. Walker, there should be considerable 
differences between the observed times for the Pamir 
earthquake and those given by the tables. From 
the absence of any such differences, Dr. Jeffreys 
concludes that the foci of the earthquakes on which 
our tables are based were not at depths greater 
than 120 km. 
In the third paper, Prof. Turner supplements a 
former note (see NATURE, vol. I10, p. 55). Observa- 
tions on the angle of emergence of earthquake waves 
at Pulkova led Galitzin to discern the existence of 
three new “‘ critical surfaces ’’ at the depths of 106, 
232, and 492 km. Prof. Turner remarks that the 
relative depths of earthquake foci also concentrate 
about three chief values. The absolute depths are 
unknown, but, if they are the same as those of 
Galitzin’s surfaces, they result in a surface value of 
the P waves agreeing with that obtained from the 
Oppau explosion, and suggest that destructive earth- 
quakes probably originate in the uppermost layer, 
at a depth of 106 km. 
Prof. Omori attacks the question from a different 
point of view, but also depends on time-observations 
(Japanese Journ. of Astr. and Geoph., vol. 1, 1922, 
abstracts p. 16). He finds that the distance (7 km.) 
of a station from the earthquake centre and the 
duration (y sec.) of the first preliminary tremor at 
the station are connected by the relation *=7-42y. 
From observations made at three stations (Tokyo, 
Mito, and Choshi), he finds that the focal depths of 
ten earthquakes felt at Tokyo in 1919-1921 range 
between 27:5 and 46:0 km., with an average of 
34 km. In a later paper (Seismol. Notes, vol. 1, 
No. 3), he assigns, by the same method, a depth of 
48 km. to the focus of the semi-destructive Tokyo 
earthquake of April 26, 1922. C. D. 
