on I cecal ail 
NOVEMBER 30, 1916] 
NATURE 
257 
WE have received a little book by Mr. J. W. Giltay 
dealing with bow instruments from a physical point of 
view (“De Strijkinstrumenten uit een natuurkundig 
oogpunt beschouwd”’; Leyden, 1916, pp. xi+ 103, illus- 
trated). It is a simple description of the action of the 
various parts of the violin, with a reference here and 
there to other bowed instruments. An elementary 
knowledge of acoustics is assumed. The book should 
appeal in the first place to musicians taking a scientific 
interest in their instruments, and in the second place to 
physicists. For the most part the author describes 
and discusses the results of earlier workers, especially 
those of Savart, Helmholtz, and Sir William Huggins, 
but he has also included a number of his own experi- 
ments, particularly on the effect of the air volume 
enclosed in the sounding-box. He is not convinced 
that a violin improves by being played upon. 
Tue ‘Catalogue (No. 369) of Miscellaneous Litera- 
ture’? just issued by Mr. F. Edwards, of High Street, 
Marylebone, though mainly consisting of books of 
general interest, contains particulars of several works 
appealing to readers of NarurE—on botany, travel, 
and, notably, natural history. The catalogue directs 
attention to many publications of the Zoological Society 
of London, offered, for the most part, at greatly re- 
duced prices. 
OUR ASTRONOMICAL COLUMN. 
EPHEMERIS OF Comet 1916) (Wor@).—After having 
passed conjunction, this comet will again be in a 
favourable position for observation as a morning star 
during the winter and spring. The following 
ephemeris for Greenwich midnight is given by Mr. 
R 
- T. Crawford in Lick Observatory Bulletin 
No. 286 :-— 
R.A Decl R.A. Decl. 
he on: Ss. i Pam, «5. iy 
BeGe tas Go 40 5.13 Jan.29 16 59 56 —5 15 
10 25 10 S147) | Mebie or oat 2 4 28 
20 239 5.50 18 42 49 3 24 
30 16 0 53 605 20 0B 523 es! 
Jan. 9 19 50 6 2) Mar. 5 16 35 Weis 
1) 39 32 5 46 
The values of log A on December 1, December 31, 
February 1, March 1, are 0-5829, 0:3237, 0:4434, 0-3623 
respectively. Taking the brightness at discovery on 
May 10-as unity, the theoretical brightness on these 
dates is 3-0, +9, 8-8, and 15-6. The path of the comet 
during the above period is mainly through Ophiuchus. 
Tue Great Rep Spor on Jupirer.—This planet 
being now favourably visible in the evening sky, 
observations can be conveniently made of the surface 
markings, which are very abundant and diversified 
at the present time. The red spot is smaller than 
formerly, and the hollow in the great S. equatorial 
belt less prominent. The first-named object will be 
central at about the following times :— 
h. m. h. m. 
Dec. 3 9 35 Dec. 13 7 50 
4 5 26 He g 28 
6 7 & 18 6 59 
Q > : 
8 8 43 BON Vs, a > Oa 
Io 10 21 hy adore 9 23 
II 6 12 BOk 6 52 
Mr. F. Sargent, of Bristol, who has been observing 
this planet with. considerable success in recent years, 
informs Mr. Denning that the large dark spot in the 
S. tropical zone, known as the “south tropical dis- 
turbance,”’ is now about 120° long, so that it extends 
over one-third of the circumference of Jupiter.. The 
middle of this “‘disturbance” follows the middle of 
the red spot about two and a half hours, and the 
NO. 2457, VOL. 98] 
-and Miss Strover at Bexley Heath. 
preceding end of the former may be expected to over- 
take the following end of the latter at the end of 
January. Since June, 1914, the rate of rotation of the 
red spot has been about gh. 55m. 37s., and this rate 
may be expected to exhibit an acceleration next year 
when involved with the S. tropical disturbance. 
THe Metroric SHOWER FROM BieELA’s ComET.— 
Though no rich display occurred this year, it is in- 
teresting to note that this shower visibly returned. 
Between November 20 and 24 ten slow meteors were 
recorded giving a fairly well-defined radiant at 27°+42° 
near y Andromeda. These meteors were seen by 
various observers, including Mr. Denning at Bristol, 
Mrs. Wilson at Totteridge, Miss Cook at Stowmarket, 
It seems prob- 
able that a few of these Andromedids are visible every 
year, and that meteors are distributed completely 
around the cometary orbit, though sparingly in sec- 
tions of it. 
Tue Contours or Stars 1N GLopuLaR CLusTERS.— 
Dr. Shapley has recently obtained further important 
data relating to the colour-indices of stars included in 
globular clusters (Proc. Nat. Acad. Sciences, vol. ii., 
p- 525). The stars in a cluster of this type may be 
supposed to be at sensibly the same distance from the 
earth, and apparent magnitudes may accordingly be 
assumed to be directly proportional to the total light 
emitted. In four clusters which have now been fully 
investigated, it has been found that the average colour- 
index is distinctly greater for the brighter stars than 
for the fainter ones, or that relatively high luminosity 
is accompanied by greater redness. The total light 
emission of the bluer stars, for which the surface tem- 
perature is presumably in excess of 10,000° C., thus 
appears to be less than that of many of the redder 
stars, which have surface temperatures only half as 
great. Since the emission per unit area is much less 
for the red than for the bluer stars, it follows that 
in the clusters investigated the volumes of the bright 
redder stars are very great in comparison with those 
of the stars which are fainter and relatively blue. The 
ancestral relationships of the two classes must be 
accounted for in any satisfactory hypothesis of the 
evolutionary sequence of spectral types. 
FOSSIL VERTEBRATE ANIMALS. 
HE American Museum of Natural History, New 
York, has lately issued a fifth volume of papers on 
fossil vertebrata, reprinted from the Bulletin of the 
museum for the years 1913-14. It has long taken a 
leading place in researches of the kind here detailed, 
and the new contributions to our knowledge of many 
groups of extinct vertebrate animals are of the usual 
interest and importance. Besides the members of the 
staff, the authors include other well-known American 
paleontologists, while Dr. Robert Broom and Baron 
F. von Huene make specially interesting contribu- 
tions, having studied the American fossils after their 
long experience of corresponding specimens from South 
Africa and Europe. Dr. Broom has, indeed, furnished 
the American Museum with a large collection of South 
Africa Permo-Triassic reptiles for comparison with the 
contemporaneous American groups, and he describes 
many of his specimens in the volume before us. 
Several studies of the early reptiles and labyrinth- 
odonts are appropriately followed by Dr. Broom’s dis- 
cussion of the structure and affinities of the Mesozoic 
multituberculate mammals and their rare Eocene suc- 
cessors. His description of a new skull of Poly- 
mastodon is especially interesting, and he agrees with 
the usual opinion that some of the herbivorous multi- 
tuberculates were the ancestors of the existing mono- 
tremes. The latest forms of extinct land-reptiles from 
