JuLy 24, 1902] 
baryta, on circulating repeatedly by means of a mercury circu- 
lator through a fresh quantity of baryta, gave appreciable 
amounts of barium carbonate corresponding to the production of 
amounts of carbon dioxide of an order nearly approaching, in 
some cases, the amount of carbon dioxide originally in the air. 
These facts were so extraordinary that the Academy appointed 
a commission, consisting of MM. Armand Gautier, Haller and 
Ad. Carnot, to repeat and report on this work. Their report is 
published in the current number of the Comptes rendus, and 
they confirm in every particular the views originally stated by 
MM. Henriet and Pécoul. M. Henriet also publishes in the 
same number an account of an attempt made to determine the 
nature of the gaseous substance present in the air capable of 
giving these results, and comes to the conclusion that there is 
present in the air of Paris the vapour of asubstituted formamide, 
the slow hydrolysis of which by the baryta furnishes the carbon 
dioxide originally found. 
THE additions to the Zoological Society’s Gardens during the 
past week include a Black Lemur (Zemur macaco) from 
Madagascar, presented by Mr. Thomas Watson ;a Hybrid 
Zebra (between Eguus burchelli and £. caballus) from South 
Africa, presented by H.M. The King ; a Caracal (/e/is caraca/) 
from South Africa, presented by Regimental Quatermaster- 
Sergeant Glenton, L. R. ; two Javan Peafowls ( Pave spicifer) from 
Burmah, presented by Mr. O, F. Wheeler Cuffe ; a Ouzel 
(Meru/a, sp. inc.) from India, presented by Miss Porter ; thirteen 
Slow-worms (Angus fragilis) British, presented by Mr. C. J. 
Frielander ; a Mongoz Lemur (Zemzr mongoz) from Madagascar, 
seven Cunningham’s Skinks (Zygernia cunninghamz) from 
Australia, four Amphiumas (Amphiuma means), a Corn Snake 
(Coluber guttatus) from North America, two Ruddy Sheldrakes 
( Tadorna casarca) European, deposited ; a Wapiti Deer (Cervus 
canadensis, 6) from North America, purchased. 
OUR ASTRONOMICAL COLUMN. 
BriGHT METEOR OF JULY 13.—Several letters referring to 
observations of the bright meteor of July 13 have been received, 
in addition to those mentioned last week (p. 281). 
Mr. O. J. R. Howarth observed the meteor at Chelsea, his 
attention being attracted by a flash resembling a very powerful 
searchlight, of a bluish hue, which lit up the sky and street 
brightly for an instant. ‘‘ On turning to discover the cause a 
trail of light of considerable breadth (perhaps 1°) was observed. 
It was of serpentine form, about 10° in length, of a granulated 
appearance, and gradually faded from a bright golden colour, 
remaining visible from eight to ten seconds. Its elevation was 
estimated at 60°, and its direction was about S.E. from 
Chelsea.” 
Mr. W. Gilles, observing at Deal, says :—‘‘ The meteor be- 
came visible about 10° S. of the zenith and left a luminous 
trail of a remarkably sinuous character at its commencement, 
which was visible for about one minute afterwards.” 
RADIAL VELOCITY OF THE ORION NEBULA.—In No. 5, 
vol. xv. of the Astrophysical Journal, Prof. H. C. Vogel gives 
an interesting description of the methods employed, and the 
results obtained, by Dr. Eberhard and himself in determining 
the radial velocity of the Orion nebula. 
The spectrograms were obtained by Dr. Eberhard with a 
photographic refractor of the Potsdam Observatory, which has 
an aperture of 32°5 cm. and a focal length of 343 cm. Owing 
to the lens not being fully corrected it was impossible to photo- 
graph lines of greater wave-length than Hy. An exposure of 
180 minutes, using a three-prism spectrograph, gave a spectrum 
in which, at Hy, 0°25 mm. corresponds to a difference of 
0°424 wu, whilst an electrical heating apparatus enables the 
observer to maintain a constant temperature in the prism box 
within a tenth of a degree for several hours. 
Seven spectrograms, taken between November 22, 1901, and 
February 22, 1902, each showing two iron comparison spectra in 
addition to the nebula spectrum, gave very uniform results, the 
mean of which, as measured by both observers, indicates a 
NO. 1708, VOL. 66] 
NATURE 
399 
velocity of recession, relative to the sun, of 17°4+1 km., and 
this agrees very well with the 17°7+1°28 km. obtained by 
Keeler as the velocity of this object in his classical researches 
on the velocities of nebulz. 
Several drawings of the Hy line which are given plainly 
indicate the existence of differential velocities in various parts 
of the nebula. 
MorTION OF THE PoLE.—In No. 523 of the Astronomical 
Journal, Dr. J. C. Chandler directs attention to the apparent 
existence of a fifteen months’ periodical motion of the pole, which 
has not yet been identified. This apparent motion is so minute 
(005) that Dr. Chandler hesitates to assert its real existence, 
but at the same time he cannot account for the constant differ- 
ences in the coordinates by any other supposition, and he sum- 
marises his article with the following statement :—“‘ In dealing 
with a phenomenon so obviously complex as these motions of the 
earth’s axis are, and until we are certain of the superior limit of 
precision in astronomical measurement, it would be unphilo- 
sophical to ignore without examination such indications as 
these.” 
PHOTOGRAPHS OF THE PERSEIDS IN 1901.—M. J. Sykora 
communicates to the current number of the AZemorie della Socteta 
degli Spettroscopisti Italiané the results obtained by the staff of 
the Jouriew Observatory (Dorpat) in photographing the Perseid 
trails in August, I90I. 
Seven meteor trails were found on the negatives obtained, 
but of these two were evidently not due to Perseids. Of the 
remaining five, two were remarkable, inasmuch as they show 
the explosion of meteors, one in the middle of its trail, the 
other at the end of its trail; drawings of these accompany the 
article. 
Measurements of the trails in regard to the coordinates obtained 
from stellar images on the same negatives give the radiant point 
for August II as 
a=43 558 3=57° 10'°3, 
whilst the radiant point for August 12 is evidently slightly east 
of this position. 
VARIABLE STARS.—2815 U Geminorum.—Mr. J. A. Park-~ 
hurst has observed the latest maximum of 2815 U Geminorum 
with the 12-inch and 4o-inch refractors of the Yerkes Observa- 
tory, and finds a range of 3°04 magnitudes between April 3 and 
May 8, the maximum (9°76 m.) being attained at 13°9h. on 
April 14. 
Mr. Paul A. Yendell, of Dorchester, U.S.A., has made obser- 
vations of the four following variable stars :— 
2279 T Monocerotis.—Eleven observations of this star in 1900, 
and forty-six from December 1, 1901, to April 24, 1902, show 
four minima and five maxima. 
2335 WW Geminorum.—Fifty-one observations extending 
from November 24, 1901, to April 28, 1902, indicate five maxima 
and one minimum. 
2509 ¢ Geminorum.—Four maxima and three minima are 
deduced from thirty-two observations of this star made between 
December 27, 1901, and May 2, 1902. 
2676 U Monocerotis.—Twenty observations from January 13 
to April 14, 1902, include a minimum of 7°t m, on January 30 
and a maximumof 6°2m. on February 12. (Astronomical Journal, 
No. 523). 
THE AUGUST METEORIC SHOWER. 
LIKE the great majority of meteoric streams, the Perseids 
return every year, and if they do not compose a really 
brilliant display they form a very noteworthy shower. An 
observer attentively watching the firmament on about August 
II may sometimes count 100 meteors in an hour, but the moon 
must be absent and the atmosphere very clear. In those years 
when it is most conspicuously exhibited it well repays observa- 
tion even by those persons who do not specially apply themselves 
to this department of astronomy. At the close of July and open- 
ing of August there are comparatively few Perseids visible, but 
there is a rich shower of Aquarids at that particular epoch, so 
that meteors are generally pretty numerous, and occasionally 
surprisingly so. : 
Watching for these objects on ordinary nights is sometimes 
apt to prove tedious even to enthusiasts, but the Perseids are 
always sufficiently frequent and brilliant on about August 10, 
11 and 12 to attract the interested attention of the most casual 
