Soe 
NATURE 
[ FEBRUARY II, 1897 
OUR ASTRONOMICAL COLUMN. 
THE PERIOD OF ROTATION OF JUPITER’s SpoTs.—Herr 
A, A. Nyland communicates to Astronomischen Nachrichten 
(No. 3401) his observations of Jupiter's markings, made at 
Utrecht with a refractor of 26 cm., and of focal length 320 cm. 
The object he had in view was to determine the period of 
rotation of this planet in different Jovian latitudes, and to 
accomplish this he observed the transits of eleven different 
spots across the smaller axis of the planet’s disc. The results, 
as regards two spots, a and #, is given in the following tables, 
in which the second column shows the number of rotations, and 
the third the time of rotation. 
Sfot a. 
Period of 
1895-6. No. Rotations. Rotation. 
Wy ia 
Nov. 23—Dec. 10 on 41 9 55 23°7 
Dec. 10—Feb. 11 a EEC 32°0 
Feb. 11—Mar. 10 08 68 eee 35°5 
Mar. 10—Apr. 25 III 32°1 
Spot b. 
Period of 
1895-6. No. Rotations. Rotation. 
oe as 
Nov. 18—Dec. 22 82 330 9 55 28°5 
Dec. 22—Feb. 8 116 Bo 34 6 
Feb. 8—Mar. 13 a0 82 34°7 
Mar. 13—Apr. 2 104 38°2 
It will 
be noticed that the spot 4 appeared to have a longer 
period of rotation than a, the former transiting after the latter 
according to the formula 
th. 45m. 1s. + 7°2s. x (¢ — 1. Jan. 1896 in days). 
Observations of the ‘‘red spot” gave no indications of a 
diminution in the time of rotation. In the case of the other 
spots, it was found that they were too variable in their nature 
for such a determination to be made, as some split up into two 
and sometimes three parts, while others varied in their bril- 
liancy and became hard to identify. 
THE SPECTRUM OF ¢ Puppis.—A Harvard College Observa- 
tory Circular (No. 16) contains some additional information to 
that which we gave in this column on November 26 of last year, 
concerning the spectrum of the star ¢ Puppis. It was at first 
suggested that the second series of rhythmical lines was due to 
some unknown element, but it has now been concluded that such 
is not the case. A further investigation has shown that this 
series is very closely allied to that of hydrogen, and is probably 
due to that substance under conditions of temperature or pres- 
sure as yet unknown. A slightly modified form of Balmer’s 
formula, namely, i 
a 304672 n*— 16 
gives the wave-lengths of the lines of hydrogen if for 2 the 
even integers 6, 8, 10, 12, &c., be substituted. If in this 
formula the odd integers 5, 7, 9, 11, &c., be inserted for, then 
the wave-lengths represent the second series of lines in 
¢ Puppis. The following brief table shows in the first column 
the value of 7, in the second the computed wave-lengths by the 
above formula, and in the third the mean of two series of 
measured values. 
n Computed. Observed Mean. 
5 10128'1 oe — 
7 - 5413°9 eee = 
9 5 45436 an — 
II aan 4201°7 Set 4200°4 
13 Kes 4027°4 4026°8 
15 des 3925'2 3924'°8 
17 =o 3859°8 3858°7 
19 538 3815 2 3815°9 
21 ees 3783"4 3783 "4 
Comparing the spectrum of ¢ Puppis with other stellar spectra, 
the four lines between Hy and H8 have probable wave-lengths 
of 4472, 4544, 4633, and 4688. The first is a prominent Orion 
star line, while the second is well-marked, and is the line com- 
puted above when x=9. All these four lines appear in 29 
Canis Majoris, and three lines of the above series are measur- 
able in the photograph of this star. 
NO. 1424, VOL. 55] 
THE SpPecrRroscopic BINARY a! GEMINORUM.—In the 
current January number of the Astrophysical Journal, Herrn. A. 
Belopolsky gives the results of his investigation of thirty-two 
spectrograms which he has obtained of the binary star a! 
Geminorum. This star required one hour's exposure, and a 
comparison with the spectrum of hydrogen was photographed 
at half-time. Using all the available data, Herrn. Belopolsky 
determined a series of values for the velocity in the line of 
sight, and after correction for the sun, found a periodic change, 
having a period of about 2°9 to 3‘o days. In the table which 
he gives, showing the velocity relative to the sun, he found that 
the curve of velocities satisfied either the first nine points 
(taken in January and February of 1896), with the exception of 
the eighth or the remaining twenty-four points, and that a single 
curve could not be drawn that would satisfy all the observ- 
ations. This discrepancy, he remarks, suggested that the 2°91 
days’ period could not be used throughout the whole time 
covered by the observations. Applying a correction to the 
abscissee for these dates, and drawing a fresh curve, he com- 
puted another series of velocities from the new elements. Even 
then slight discrepancies existed for these points, which, as he 
says, ‘‘cannot be explained with certainty at present.” A 
possible cause is suggested in the rapid motion of the line of 
apsides in the direction of the orbital motion of the star, as was 
shown in Duner’s analogous investigation of y Cygni, in which 
a disturbing force, due to a flattening of the central body, exists. 
NANSEN'S ARCTIC EXPEDITION. 
A MEETING of the Royal Geographical Society was held 
on the evening of Monday, February 8, in the Albert 
Hall, when Dr. Fridtjof Nansen gave an account of the pre- 
liminary results of his great drift-journey in the Ayam across the 
Polar area, and his sledge expedition northward. The Prince 
of Wales, the Duke and Duchess of York, and almost all the 
veteran British Arctic officers were present, while the great hall 
was crowded with the Fellows of the Society and their friends. 
Selections of Norwegian national music were played on the 
organ as the audience was arriving, and the appearance of Dr. 
Nansen and his companion, Lieut. Scott Hansen, on the plat- 
form was received with the greatest enthusiasm. Sir Clements 
Markham, K.C.B., F.R.S., President of the Society, intre- 
duced Dr, Nansen in a few words, and the explorer then 
addressed the meeting. During the address a large selection of 
photographs was shown by thelantern ona 40-foot screen ; some 
of the pictures were taken by moonlight dering the Arctic 
winter, and were extremely impressive, others were coloured re- 
productions of Dr. Nansen’s sketches, including some fine sun- 
set and aurora effects. Admiral Sir Leopold McClintock pro- 
posed, and Admiral Sir George Nares seconded, a vote of thanks 
for the address, in which they expressed their unqualified ad- 
miration of the manner in which Dr. Nansen had conducted his 
unique expedition. The Prince of Wales, as Vice-Patron of 
the Royal Geographical Society, then presented Dr. Nansen 
with the special gold medal of the Society, bearing the bust of 
the recipient on one side, and a representation of the Ava on 
the other. A copy of the medal in silver was presented to 
Lieut. Scott Hansen, and copies will be sent to the other 
members of the scientific staff of the 7a, while bronze re- 
plicas are given to the other members of the expedition. In 
thanking the Society for the medal, Dr. Nansen said that he had 
succeeded only by following the labours of his predecessors, the 
British Arctic officers, for whose heroism and resourcefulness he 
had the highest respect and admiration. 
A large part of the address was necessarily occupied by de- 
scribing the incidents of the journey already published im 
NATURE (vol. liv. p. 374). The following is a summary of the 
preliminary scientific results obtained by Dr. Nansen, and 
referred to during his address :— 
Our expedition was intended to be purely a sea-expedition, 
the object of which was to drift with the drift-ice and keep clear 
of all land, so that we thought ourselves fortunate in avoiding 
the discovery of any extensive land. After passing through the 
Kara Sea the Fram skirted the north of Asia from the east of 
the Yenesei estuary to longitude 115° E. near the mouth of the 
Olenek. Off the western Taimyr peninsula an archipelago of 
small islands was encountered, through which it was difficult to 
find a passage ; these I have named Nordenskiold Islands, after 
