DECEMBER 4, 1913]| 
OUR ASTRONOMICAL COLUMN. 
Tue Rapiat VELocITy OF THE ANDROMEDA NEBULA. 
Lowell Bulletin (No. 58) contains an important com- 
munication by Mr. V. M. Slipher, which gives a first 
approximation to the radial velocity of the Andromeda 
nebula. Mr, Slipher used the 24-in. of the Lowell 
Observatory, with a camera of very short focus, a 
wide slit, and a very dense prism of 64°. The first 
of the series of spectrograms was exposed for 6h. 50m., 
but no mention is made as regards the lengths of the 
exposures of the other plates. The observations re- 
corded are as follows :— 
1912 Velocity 
September 17 ae = « —284 km. 
November 15-16... eee eee 200° ,, 
December 3-4 aS —308 ,, 
December 29-30-31 —301 ,, 
Mean velocity ... —300 ,, 
Mention is made that tests for determining the 
degree of accuracy of such observations have not been 
completed, but the mean value is stated to be within 
the accuracy of the observations. As the Andromeda 
nebula is typical of a very great number of nebulz it 
will be interesting toknow whether other spirals have 
a movement of the same order, and thus exceed as a 
class the velocities of stars. The faintness of spiral 
nebulz renders the accumulation of data on this point 
a very slow process, but an attack on a few of the 
brighter ones would be of great importance and might 
indicate the general tendency of the velocity mag- 
nitude. 
PHOTOGRAPHIC MAGNITUDES OF COMPARISON STARS IN 
CERTAIN OF THE HaGEN Fie_ps.—It was with the object 
of establishing the photographic magnitudes of stars 
which might be used as standards for comparison in 
the Hagen fields that Mr. C. H. Gingrich undertook 
the research which he describes in the October number 
of The Astrophysical Journal, The instruments avail- 
able at the Yerkes Observatory for the research were 
a 6-in. Zeiss ultra-violet camera and a 2-ft. reflector; 
the former instrument was used for the bright stars, 
and the latter for faint stars, though in this case the 
exposures were considerably lengthened owing to the 
necessity of having to cut the aperture down to rift. 
Mr. Gingrich describes in some detail the programme 
of exposures and the methods of measurement and 
reduction. The results are summed up in ten tables, 
each including a field. 
THe HarMonic ANALYSER APPLIED TO THE SUN-SPOT 
CycLte.—In a recent number of The Astrophysical 
Journal (October, vol. xxxviii., No. 3) Prof. A. A. 
Michelson gives the results of a determination of 
periodicities by the harmonic analyser with an appli- 
cation to the sun-spot cycle. The method employed 
is to obtain the values of the coefficients of a Fourier 
series by a mechanical integration by the harmonic 
analyser. The function to be treated is copied «n the 
machine, which then draws a curve the ordinates of 
which at given distances along the axis of abscissas 
are proportional to the coefficients of the correspond- 
ing Fourier series. In the present paper he gives a 
few test illustrations of the performance of the 
machine, and refers to a similar treatment of the 
sun-spot curve, as furnished in the paper by Hisashi 
Kimura, entitled ‘On the Harmonic Analysis of Sun- 
spot Relative Numbers,”’ printed in the Monthly 
Notices, R.A.S., May, 1913, p. 543. Prof. Michelson 
concludes his paper with the statements that it would 
seem that with the exception of the eleven-year period 
and possibly a very long period (of the order of 100 
years) the many periods found by previous investi- 
NO. 230I, VOL. 92] 
NATURE 
4II 
gators are illusory. He adds that it will probably be 
found that even the eleven-year period is, in fact, not 
constant, but is subject to secular change. 
R.Z. Casstopr1a.—A research by Herr K. Graff on 
this important short-period eclipsing binary system is 
published in No. 13, Mitteilungen der Hamburger 
Sternwarte. It is pointed out that this system is 
pre-eminently fitted for study with small instruments 
since it is circumpolar, occupies a_ well-marked 
position lying in the prolongation of the line 
e to . Cassiopeiz, the range of magnitude is important 
(6-36 to 7-69 in the course of rather less than three 
hours), and it has a very short period, 1-19525d. 
Tue NssiruckeT OpseRvaAToRY.—The new 73 in. 
photographic telescope has been placed in position in 
the Memorial Observatory of the Nantucket Maria 
Mitchell Association. The observatory has, in addition, 
a 5-in. Alvan Clark visual telescope, a filar micrometer, 
and a micrometer for measuring stellar spectra, The 
Nantucket Maria Mitchell Association has awarded | 
the fellowship of 20o0l. for the year beginning June 15, 
1914, to Margaret Harwood. In order that the ob- 
servatory may be provided for from June 15, 1915, 
to December 15, 1915, the association offers a second 
fellowship of rool. for the quadrennial year under 
conditions similar to those which have governed the 
2ool. fellowship. The committee reserves the right to 
withhold the second rool. fellowship in case the work 
presented to the examiners should not in their judg- 
ment be of sufficient merit to deserve the award. 
CONVERGENCE IN THE MAMMALIA. 
CBs discussion on convergence in mammalia in 
Section D at the recent meeting of the British 
Association was, to some extent, a consideration of 
matters kindred to several dealt with by Dr. Gadow 
in his presidential address. In his prefatory remarks 
Dr. Gadow referred to the importance of perceiving 
convergent resemblances, and said it was of more 
value to understand how and why, for instance, even 
a small but essential Cetacean feature had been 
brought about than to refer it back to some “ Ur- 
Cetacean,” which would still remain a mystical con- 
ception. 
Prof. Dollo discussed a new case of convergence, 
namely Balzna and Neobalena. He pointed out that 
Neobalzna, a whale with long whalebone, and found 
in the southern hemisphere, had been considered 
hitherto either as a true right-whale or as intermediate 
between the right-whales and the fin-whales. He held 
that Neobalzena does not belong to the right-whales, 
and that all the characters which it possesses in common 
with them are adaptations. Nor is Neobalzena inter- 
mediate between the right-whales and the fin-whales, 
but belongs to the latter group, for all the features 
which it has in common with the fin-whales are 
hereditary characters. Rhachianectes is not a primi- 
tive fin-whale; it is very specialised and secondarily 
adapted to littoral life and to its mytilophagous habit. 
Its hyperphalangy bears witness to its former pelagic 
life, and its shortened whalebones to its former 
plankton-feeding habit. The Mystacoceti should be 
divided into (1) Balznoidea, including a single family 
—the Balenidz, with long whalebones, and (2) 
Balznopteroidea, comprising three families—Balzeno- 
pteride, with short whalebones, Rhachianectide, 
with regressive whalebones, and Neobalenidz, with 
long whalebones. Neobalzena is an example of posi- 
tive convergence with Balzna by independent acquisi- 
tion of the longibarbous character, and, on the other 
hand, is an example of negative convergence with 
Rhachianectes by reason of the loss of the throat- 
grooves. 
