Jory 23, 1914] 
NATURE 
539 
piece of chromatin like that described as an “odd 
chromosome” by Guyer. As the structure is present 
in spermatocytes of both orders, and varies in shape, 
size, and number, the authors conclude that it cannot 
be an ‘odd chromosome” at all. 
In the Izvestiya of the Eastern Siberia branch of 
the Russian Geographical Society, Mr. M. Nikitin 
gives some results of the levelling operations carried 
out by Captain Kremlyakof in connection with the 
Siberian railway. The mean height of Lake Baikal 
is calculated to be 1485 ft. Other figures are Irkutsk 
(railway station), 1410 ft.; Mysovaya, 1514 ft.; 
Verkhneudinsk, -1763 ft.; Petrovski Zavot, 2627 ft. ; 
Chita, 2150 ft. 
Tue geology of the islands in the Arctic Ocean, 
discovered by Captain Vilkitski (vol. xcii., p. 456), 
is described by Messrs. Baklund and Tolmachef in 
the Bulletin of the Imperial Academy of Sciences of 
St. Petersburg (No. 10, 1914). The island General 
Vilkitski is connected as regards its geological 
structure with the adjacent New Siberia islands, 
while those lying off the Taimyr peninsula 
are similar to the latter. Thus the specimens 
collected on Emperor Nikolas II. Land are 
of rocks found on Cape Cheliuskin, and also 
found by the expedition on the eastern coast of the 
Taimyr peninsula. Emperor Nikolas Land is there- 
fore a northern continuation of the peninsula, now 
separated from it by a strait some tens of miles in 
breadth, in which lies the island Tsesarevich Alexis, 
built up of detritus from the Taimyr peninsula, 
especially from the western coast. The Emperor 
Nikolas Land is, however, known at present only 
at two points, and future investigations may materially 
modify present conclusions. 
AN interesting article by Dr. A. E. Douglass, on 
a method of estimating rainfall by the growth of 
trees, was published in the May number of the Bulletin 
of the American Geographical Society. The author 
reasons that the rings of a tree measure its food 
supply, and that the latter, especially in the dry 
climate of the plateau of Arizona, which is dealt with, 
depends largely upon moisture. With the cooperation 
of other men of science curves of tree growth were 
prepared, and the connection with rainfall and 
possibly with astronomical phenomena was _in- 
vestigated. Dr. Douglass states that the method 
of measurement consisted of determining the 
thickness of each annual ring in millimetres 
along some typical radial line. The average 
age of the trees (yellow pine) was 348 years, with two 
extending to 520 years. The total number of indi- 
vidual measurements exceeded ten thousand. For any 
detailed description of the laborious investigation we 
must refer to the original article; the conclusion states 
that the purpose of the work has been accomplished, 
a connection has been found between tree growth and 
rainfall, as well as indications of association between 
meteorological and astronomical phenomena. With 
regard to the latter point due reference is made to 
investigations at Eberswalde (Germany) and elsewhere 
in connection with tree growth. 
Wel ag34; VOL: 93) 
A copy has reached us of the report for 1912-13 of 
the chief of the Weather Bureau of the U.S. Depart- 
ment of Agriculture. Referring to the aerial inves- 
tigations in charge of Prof. W. R. Blair, the report 
states that the temperature distribution up to about 
the 1-5 km. level shows the same type of diurnal 
variation as is observed at the earth’s surface. In 
the region near the 1-5 km. level a second maximum 
of temperature appears after midnight, while the 
3 p-m. to 4 p.m. maximum practically disappears. 
Above this region the 2 a.m. to 4 a.m. maximum is 
the principal, the minimum for the day being found 
at 2 p.m. to 3 p.m. or earlier. There is some varia- 
tion with the season in the times given for these 
maxima and minima. As regards the solar radiation 
investigations of which Prof. H. H. Kimball has 
charge, the report says the most interesting feature 
of the observational data for the year is the marked 
decrease in solar radiation intensities and in the 
polarisation of skylight, which was noticed first at 
Mount Weather in the observations of June 12, 1912. 
The intensity of the direct solar radiation with the 
sun 60° from the zenith averaged only about 85 per 
cent. of its normal value during the second half of 
1g12, and but little more than this during the first half 
of 1913. The polarisation of skylight averaged about 
66 per cent. of its normal value during the second 
half of 1912, and about 75 per cent. of the normal 
during the first half of 1913. 
In the Verhandlungen of the German Physical 
Society for June 15, Dr. E. Goldstein describes in 
detail some light effects he first noticed in 1902 about 
a kathode freely suspended in a gas through which 
an electric discharge was passing. In addition to 
the canal rays, which are generally observed by 
allowing them to pass to the back of the kathode 
through a small hole in it, Goldstein shows that ‘from 
a kathode consisting of two regular polygonal plates 
close together, bundles of canal rays are projected 
outwards from the middle of the sides or from the 
angles of the polygons according as they have an_ 
even or an odd number of sides. By taking circular 
electrodes from which strips have been cut at the 
edges or into the edges of which notches of various 
shapes have been cut, he is able to show that these 
outwardly directed canal rays are due to the focussing 
of inwardly directed canal rays within the two sheets 
of the kathode and to the strong ionisation produced 
at the focus. Their direction is that of the minimum 
path from the focus to the edge of the kathode. 
Tue Bulletin of the Imperial Society of Naturalists 
of Moscow for 1913 contains a paper of 225 pages by 
Dr. Ernst Leyst, entitled ‘‘ Variations and Disturb- 
ances of Earth-magnetism.’’ The first part deals with 
the results obtained when. the arithmetic mean is 
replaced by the ‘‘central value,’’ defined as that 
having as many positive departures from it as 
negative. The latter part of the paper discusses dis- 
turbance phenomena, mainly at Paviovsk. Dr. Leyst 
treats as disturbed all days having a range not less 
than twice as large as that of the average day of the 
average year. The qualifying ranges thus obtained 
were 29'0' in declination, 130y in horizontal force and 
