Po PII 
NATORE, 
[APRIL 30, 1914 
bility to various conditions are well appreciated and 
recognised, Sealy seedling and B147 have attained 
considerable popularity, while the more recently intro- 
duced varieties, B 4,596 and B1,528, are more promi- 
nent. The importance of incorporating with the soil 
a sufficiency of organic matter, either as pen-manure 
or green crops, is becoming more and more recog- 
nised, and the various bacterial changes concerned in 
the breakdown of these manures are discussed in this 
report in the light of recent investigations. The ex- 
treme rapidity with which such changes proceed in 
tropical climates is indicated by the fact that under 
favourable conditions the humus content of the soil 
may be decreased by as much as 25 per cent. in the 
space of six months. 
SomE interesting observations on the action of 
thunderstorms in giving rise to seiches have recently 
been made by Messrs. Okada, Fujiwhara, and Maeda 
(Proc. Tokyo Math. Phys. Soc., vol. vii., 1914, pp. 
210-221). The measurements of the seiches were 
made with a Honda limnimeter on the shores of 
Lake Biwa in central Japan. The authors indicate 
as important causes of seiches during thunderstorms 
the accumulation of rain-water over a portion of the 
lake, the impulsive action of winds on the surface, 
and sudden changes of barometric pressure; and as 
subsidiary causes the impact of falling raindrops on 
the surface of the lake and the attraction of the electrified 
mass of thunderclouds. They examine in detail the 
effects of a heavy thunderstorm that swept over Lake 
Biwa on April 19, 1912, and estimate that the change 
of barometric pressure (2-7 mm.) would account for an 
amplitude of 66 cm. in the seiches, the rainfall 
(32 mm. in twenty minutes) for an amplitude of 
6-1 cm., while the impulsive action of the wind may 
have contributed an amplitude of 4-5 cm. The sum 
of these amplitudes is 17-2 cm., which is very close to 
the total amplitude observed 
THE two last contributions to the geology of the 
Antarctic Expedition of the Belgica (‘‘ Expédition 
Antarctique Belge: Résultats du Voyage du s.y. Bel- 
gica en 1897, 1898, 1899; Zoologie, Tuniciers, Caduci- 
chordata,” by Ed. van Beneden and Marc de Selys- 
Longchamps, 1913; and ‘‘Géologie, Petrographische 
untersuchungen der Gesteinsproben,’’ part ii., by 
Dragomir Sistek, 1912) include the account of the 
tunicates and a further contribution to the description 
of the rocks collected. The memoir on the tunicates 
was begun by E. van Beneden, and after his death was 
continued and completed by M. Mare de Selys-Long- 
champs. The expedition obtained eight species, of 
which five are new and another is represented by a 
new variety. All the species collected have been de- 
scribed in elaborate detail; the memoir comprises 
120 pages, and is illustrated by seventeen plates and 
some figures in the text. The classification adopted 
is that by Hartmeyer. The new contribution on the 
petrography of the expedition is a description by D. 
Sistek of the rocks collected in the Straits of Magellan 
and the Beagle Channel, which is on the southern 
side of Tierra del Fuego. The rocks are all igneous 
or metamorphic. The most varied collection, includ- 
NO, 123225) VOLmOa|| 
ing granite, diorites, quartz-porphyries, andesite, 
diabase, basalt, gneiss, schists, and clay slate, was 
made at Cape Gregory in the Straits of Magellan. 
The crystalline schists include a varied series. The 
chief rocks are illustrated by a plate of microphoto- 
graphs of unusual clearness. . 
AN important by-product of the adjustment of the 
primary triangulation of the United States was the 
discussion of the deflections of the vertical and 
anomalies of gravity, by Mr. J. E. Hayford, on the 
hypothesis of isostatic compensation of inequalities of 
the earth’s surface. In this way the discrepancies 
between the observed and the anticipated values of 
each was very largely reduced, but, whatever the 
precise form of hypothesis used, there still remained 
an average anomaly of gravity of not less than 
0-020 dyne, which was attributed by Mr. Hayford 
to an imperfection of isostatic adjustment. Prof. 
G. K. Gilbert has taken up the subject in Pro- 
fessional Paper 85-C of the U.S. Geological Survey, 
and shows that the distridution of the anomalies of 
gravity does not indicate any relation to the leading 
features of geological structure, as would be expected 
if they were due to variation in the distribution of 
density, or imperfect isostatic adjustment, within the 
earth’s crust. From this he concludes that they are 
due, at least in part, to variations in the nuclear por- 
tions of the earth, below the limits within which 
isostatic adjustment, and compensation of elevated 
tracts of the earth’s surface, take place. 
Pror. G. A. Grsson, of Glasgow, has issued in 
separate pamphlet form the address he recently gave 
before the Royal Philosophical Society of Glasgow on 
Napier and the invention of logarithms. The 
pamphlet contains a clear picture of the career and 
personality of the great Scottish mathematician, 
bringing together within the compass of twenty-four 
pages the salient facts of his life. The interest for 
the mathematical student is the account given of the 
way in which Napier originally defined the logarithm. 
This does not correspond exactly with what is known 
as the Napierian logarithm, although it is closely 
related to it. There is a passing reference to Biirgi, 
whose ‘‘ Progress Tabulen’’ has probably been seen 
by very few mathematicians in this country. The 
evidence that Napier was in possession of his method 
at least twenty years before he published his tables 
is also referred to; and Napier’s other mathematical 
and arithmetical discoveries have as adequate a notice 
as is possible in such a brief statement. Prof. Gib- 
son’s sketch comes at an opportune time when mathe- 
maticians are preparing to celebrate the tercentenary 
of the publication of the ‘‘Canon mirificus logarithm- 
orum.”’ 
A PAPER by Messrs. K. M. Faye-Hansen and J. S. 
Peck, published in the last issue of the Journal of the 
Institution of Electrical Engineers, deals with some 
interesting uses of inductance coils or ‘‘reactances”’ 
in heavy electrical engineering. These are being used 
to an increasing extent on large power supply sys- 
tems of the order of 100,000 kilowatts for the purpose 
of limiting the current that may flow in various parts 
