94 NATURE 
{MarcH 28, 1912 
the shadow cone above sea-level will be go kim. (19 
miles) and 52 km. (324 miles) respectively. 
Further, he makes the suggestion that although 
totality may not yet occur, the corona may be seen, 
for at previous eclipses it has been seen well before 
and after totality, and in 1900 was photographed by 
Mr. Willis eight minutes after. 
Finally, he presents the peculiar possibility of there 
being neither an annular nor a total eclipse; this 
would occur if the mean apparent diameter of the 
moon were just insufficient to produce totality, because 
of the depressions at the limb, yet was so great that 
the mountains at the moon’s limb projected far 
enough to break up the continuity of the solar limb. 
In No. 4562 of the Astronomische Nachrichten Dr. 
Graff also discusses the position of the lunar moun- 
tains, and also the possible observations of the lowest 
levels of the chromosphere. He suggests, finally, that 
suitably arranged astrophysical observations may not 
prove so unprofitable as it has been generally 
supposed they must be in the circumstances of the 
coming eclipse. 
Nova GeminoruM No. 2.—A number of messages 
concerning observations of Herr Enebo’s new star 
have been received by the Kiel Centralstelle, and are 
published in No. 4562 of the Astronomische Nach- 
richten. 
At Christiania, early on March 13, Prof. Schroeter 
estimated the magnitude as 4-0, while Dr. Hartwig 
at Bamberg on March 13, at 10h. 23-9m. (Bamberg 
M.T.), found it to be 4-3; he gives the colour as 
reddish, and the position, for 1912-0, as 6h. 49m. 
11-878. +32° 15’ 6". 
On March 14 Prof. Pickering reported that the 
spectrum of the nova was of the F, type, but on 
March 15 he reported a change to a bright-line spec- 
trum. In the Harvard classification the type F.G 
represents spectra similar to that of Procyon, the 
Procyonian type in the South Kensington classifica- 
tion, which is the next earlier type to the solar stars. 
According to Dr. Hartwig, the nova corresponds 
very closely with a thirteenth-magnitude star on the 
Palisa-Wolf charts. An observation made at 11.45 
p-m. on March 20 showed the magnitude of the nova 
to be about 5-4. 
ANALYSES OF STONE MeErroritEs.—A valuable con- 
tribution to the study of meteorites appears in Publi- 
cation 151 of the Field Museum of Natural History, 
where Mr. O. C. Farrington publishes a list of 
analyses of 125 stone meteorites, and a scheme of 
classification. An ‘“‘ average’’ composition, derived 
from the whole, gives the following substances, and 
their percentages, as the principal constituents :— 
SiO, (3912), Al,O, (2°62), FeO (16°13), MgO (22'42), 
CaO (2°31), Na,O (0'81), Fe (11°46), Ni (1°15), S (1'98); 
there are thirteen other constituents. 
It is worth noting that this list does not truly re- 
present the relative spectroscopic importance of the 
various substances in meteorites. In the ‘ Spectro- 
scopic Comparison of Metals present in Certain 
Terrestrial and Celestial Light Sources,” published 
from the Solar Physics Observatory in 1907, the 
chief metals were arranged in order of the promin- 
ence of their strongest lines in the spectra of the 
eight or nine stony meteorites examined. The order 
was as follows:—Cr, Na, Al, Mg, Mn, Si, Ca, Fe, 
Ti, V, K, Sr, Ni, and Ba. 
In the spectra of all the certain meteorites, 
chromium is very well marked, vet in the chemical 
analysis given by Mr. Farrington it is only repre- 
sented by o'41 per cent. of Cr,O,. 
OpsERVATIONS OF Novza.—Observations of the 
magnitude of Nova Lacertz are published by Prof. 
NO. 2213, VOL. 89] 
Nijland in No. 4562 of the Astronomische Nach- 
richten. Between January 1 and December 15, 1911, 
the magnitude sank from 7:50 to 11-40, and the plotted 
values show practically no oscillations of the bright- 
ness. 
Observations of the suspected Nova 87-1911 Persei, 
discovered by Mr. D’Esterre, are reported by that 
observer in the same journal. The later photographs, 
showing fourteenth-magnitude stars, show, in the 
position of the nova, a nebulous patch in which 
appear to be involved three condensations or very 
faint nebulous stars. 
ELEN iN EMO! GEA ee 
ORE than twenty years have passed away since 
the veteran physiologist of Kiel—Victor Hen- 
sen—initiated a new era in plankton research char- 
acterised by the application of biometrical methods. 
His inventions and investigations culminated in the 
equipment of an oceanic expedition which was to be 
an experiment on a large scale. It was one of the 
first German scientific expeditions, and certainly the 
first oceanic expedition to be devoted entirely to the 
study of the floating organisms. 
Hensen’s pioneer work, with its enormous labour 
and brilliant negotiation of abstruse problems, was 
carried out in the face of much unfair criticism—the 
famous polemic of Haeckel, ‘‘ Plankton Studien,” will 
long be remembered by the Kiel school. 
During the years that have elapsed since, the same 
kind of destructive criticism has been at times pro- 
claimed, and almost always by those who seem to 
have taken no trouble to study the work they would 
demolish. 
The material collected by this ‘plankton’ expedi- 
tion has been examined by specialists, and now, after 
twenty-two years, Hensen has taken up the pen and 
written what should be the final volume (1), the last 
word, were it not that two or three reports still 
remain unfinished. 
The greater part of the volume deals with the 
quantitative geographical distribution of pelagic 
organisms in the North Atlantic. Numerous tables 
are appended, and these, with the reports, complete 
what must be considered the first scientific attempt 
to determine the distribution of the plankton of the 
high seas. The work as a record is of great value. 
It must be remembered, however, that the studies of 
recent years have emphasised the rema~kable seasonal 
variations occurring in the plankton of both lakes and 
seas; hence, the observations of the Hlumboldt-Stift- 
ung expedition, which lasted but three and a half 
months. must be regarded as only presenting a phase 
in the distribution of life in the ocean. 
Perhaps ‘the most interesting part of the volume 
is Hensen’s résumé, which deals with contem- 
poraneous plankton work and other problems which 
have been much discussed during the past few years, 
such as Putter’s theory and the theories of de Vries. 
The great aim of the plankton expedition was the 
determination of the actual number of the different 
organisms in the waters of the high seas. Within 
certain limits this has been carried out, but on the 
whole the figures looked at in this light are of little 
importance. It is the methodical manner in which 
quantitative nets are used, and the elimination of 
1 (x) Das Leben in Ozeannach Zahlungen seiner Bewohner : Uebersicht 
und Resultate der quantitativen Untersuchungen.’ By Prot. V. Hensen. 
(Ergebnisse der Plankton-Expedition der Humboldt-Stiftung. Bd.v. 0.) 
Pp. v+406+Tabellen (pp. 8+xxvili tables+map.) (Kiel and Leipzig: 
Lipsius and Fischer, torr.) 
(2) ‘Ueber das Nannoplankton und die Zentrifugierung kleinster 
Wasserproben zur Gewinnung desselben in lebenden Zustande.” By H. 
Lohmann, Pn. 38+5 plates. (Leipzig: Dr. Werner Klinkhardt, rorr.) 
(3) “ Leitfaden der Planktonkunde.” By Prof. A. Steuer. Pp. iv+382. 
‘ (Leipzig and Berlin: B. G. Teubner, 1911.) Price 7 marks. 
