208 
NATURE 
| DECEMBER 27, 1906 
ture concerning this material. He states that he has found 
none at present. 
papers read at the seventy-eighth meeting 
of the German Association of Naturalists and Physicians 
are published in No. 20 of the Verhandlungen of the 
German Physical Society, and also in Nos. 21 and 22 of 
the Physikalische Zeitschrift. A striking case of ‘‘ chemi- 
luminescence ’’ is described by Prof. E. Wedekind; the 
interaction of chloropicrin with magnesium phenyl bromide 
in ethereal solution is accompanied by the production of a 
green flame beneath the ether, without the latter, however, 
being caused to kindle or explode. In a dark room the 
luminescence appears very intense. An interesting lecture 
on the so-called “‘ liquid crystals’’ was delivered by Prof. 
Lehmann at a general meeting of the association; its 
general scope was to illustrate how the development of 
such “‘ crystals’? appears to mimic the phenomena usually 
supposed to be characteristic of the simplest forms of living 
matter. 
Tue physical 
A copy of a paper entitled ‘‘ Niederschlag, Abfluss und 
Verdunstung auf dem Landflachen der Erde,’’ prepared by 
Dr. Richard Fritzsche to attain his doctorate (Friedrichs 
Universitat Halle-Wittenberg), has been received. The 
paper is an attempt to re-calculate from recent data the 
total yearly rainfall over the earth’s surface, and to in- 
dicate the transference of water between land and sea. 
The flow of water through the world’s rivers is, of course, 
also considered in detail, and in this connection a very 
full list of authorities and references is given, adding 
greatly to the value of the thesis. In most cases the 
figure used is compared with that given by Murray. The 
unit adopted is the cubic kilometre per year. The total 
rainfall over the whole world is given by Fritzsche as 
465,300 cubic kilometres per year, which is equivalent to 
a uniform depth of gr centimetres; Briickner gave 94 centi- 
metres. The rain falling on land is estimated by Fritzsche 
as 111,940 cubic kilometres per year, by Briickner at 
122,540 cubic kilometres, and by Murray at 122,318 cubic 
kilometres per year. The amount given by Fritzsche is 
equivalent to a depth of 75 centimetres. Co sidering only 
the land which is drained by rivers into the sea, it is 
calculated that only 30 per cent. of the water returns to 
the sea in this way, the remaining 70 per cent. being re- 
moved by evaporation. The tables which accompany the 
paper are very full and interesting. 
Since the publication of the first edition of his ‘‘ Sinnes- 
organe im Pflanzenreich zur Perzeption mechanischer 
Reize ’”’ (Leipzig : Engelmann) in 1901, Prof. G. Haberlandt 
has continued his investigations of the sense organs, or 
organs of perception, of plants, and he includes his new 
observations in the second edition of his work just pub- 
lished. The original volume was reviewed in Nature of 
April 10, 1902 (vol. Ixv., p. 529). 
OUR ASTRONOMICAL COLUMN. 
ASTRONOMICAL OCCURRENCES IN JANUARY, 1907 :— 
Jan. 2. 7h. Neptune in opposition to the Sun. 
3-4. Epoch of January Meteors (Bodtids, radiant 
230 + 53°). 
4. 6h, Venus at maximum brilliancy. 
7- Qh. 56m. to 12h. 56m. Transit of Jupiter's Sat. IIT. 
(Ganymede). 
9. 17h. 44m. to 18h. 20m. Moon occults y Libre 
(mag. 4'1). 
10, 17h,12m. Moonin conjunction with Venus. Venus 
o 17’ N. 
13. Total eclipse of Sun, invisible at Greenwich. 
14 13h. 13m. to 16h. 13m. Transit of Jupiter’s Sat. III. 
(Ganymede). 
NO. 1939, VOL. 75 
Jan. 16. Venus. Illuminated portion of disc =0 353. 
7. th. 28m. Minimum of Algol (B Persei). 
20. Sh. 17m. Minimum of Algol (8 Persei). } 
I. gh. 7m. to 104. 12m. Moon occults €¢? Cetp 
(mag. 4°3). aga 
24. Neptune }° N. of 36 Geminorum (mag. 5°2). 
26. 2h. 4m, Jupiter in conjunction with Moon. Jupiter 
omer 
», 6h. 4om. to 7h. 45m. Moon occults » Geminorum. 
(mag. 4°I). 
28-29. Partial eclipse of Moon, invisible at Greenwich 
Comets 1906h (MerrcaLF) AND 1906d (FINLay).—Fron> 
observations made at Mount Hamilton and Rome, Herr 
M. Ebell has calculated a set of elliptic elements for 
comet 1906h, after finding that the observed places could 
not be satisfied by a parabola. The time of perihelion 
passage, according to these elements, was October 10.794 
(Berlin), and the period of the comet is 7-588 years. The 
elements exhibit a similarity to those of comets Faye, Wolf, 
1892 V., 1896 V., and 1900 III., but it is improbable that 
comet 1906h is identical with any of these, although it 
probably belongs to the same family. An ephemeris ex- 
tending to January 28 is also given by Herr Ebell, but, as 
the comet is so extremely faint, it is not worth while to 
reproduce it here. 
On December 8 Prof. Hartwig, at the Bamberg Observ- 
atory, examined the neighbourhood of the comet, and of 
the star B.D.—3°-696, with a 10-inch refractor, for the 
nebulous objects seen at Bordeaux on November 22, but 
was unable to find them (Astronomische Nachrichten, 
No. 4141). 
An ephemeris extending to March 22 is given for comet 
tg06d in No. 4140 of the Astronomische Nachrichten by 
M. L. Schulhof. This object is now very faint, and is 
about 134° south of Pollux. 
Two Stars witH a Common Proper Motion.—In vol. 
Ix. of the Monthly Notices of the Royal Astronomical 
Society, Mr. Bellamy announced that the two stars 
AG Berlin B 5072-5073 have a common proper motion, and 
this was confirmed later by Prof. Kreutz. Additional 
confirmation now comes from Prof. Millosevich, who has 
compared the available observations since the year 1881 
with more recent ones, the last of which was made at 
Rome at the epoch 1906-39, and finds the proper motion 
on a great circle to be 1”-385 in the direction 142° 7’ 
(Astronomische Nachrichten, No. 4132). 
OBSERVATIONS OF VeENUS.—Continuing his articles on 
““ Planets and Planetary Observation ’’ in the Observatory, 
Mr. Denning discusses the observation of Venus in No. 377, 
and points out that the difficulties attending such observ- 
ations have hitherto prevented any final determination of 
the planet’s rotation period, or of the nature of her surface 
markings. : 
He also states that the best times to observe the planet 
are during the evening apparitions in the early part of the 
year and the morning apparitions which occur in the latter 
half of each year, when Venus is above the horizon for a 
long time after sunset or before sunrise. The chief observ- 
ations of reputed surface markings which have been made 
Mr. Denning’s notes. 
A Brituiant Meteor.—Mr. H. E. Wood, of the Govern- 
ment Observatory, Johannesburg, records, in No. 4141 of 
the Astronomische Nachrichten, the observation of a 
brilliant meteor on July 16 in various parts of South Africa. 
An observer at Mbabane, in Swaziland, describes the object 
as a large white ball with a long trail of sparks, and states 
that it split into two masses each larger than the full 
moon, whilst a loud explosion accompanied its disappear- 
ance. Attempts to locate the object, which apparently 
struck the earth near to Mbabane, have been unsuccessful. 
Mr. Wood himself saw a meteor, which he believes to have 
been the same object, at Johannesburg, two hundred miles 
away, at 8h. 45m. p.m. (standard time of 30° E.), but he 
heard no detonation, although the object was very brilliant 
and left a trail of sparks. As a similar body was observed 
in Germany on the same evening, Mr. Wood suggests that 
possibly the earth encountered a stream of meteoric bodies 
on July 16, and that both the observed meteors were 
members of the same stream. 
hae the time of Galileo are discussed at some length in. 
