AprIL 18, 1907 | 
NATURE 
OUR ASTRONOMICAL COLUMN. 
A New Comer (1907b).—-A telegram from the Kiel 
Centralstelle announces the discovery of the second comet 
of the present year by Mr. Mellish, at Madison, on 
April 14. The magnitude of the object is given as 11-0, 
and its position at roh. 20m. (Madison M.T.) on the day 
of discovery was R.A.=6h. gom., dec.=+8° 0’. 
A second telegram from Kiel states that the comet was 
observed by Bianchi at Rome on April 16. Its position 
at 8h. 22-1m. (Rome M.T.) was 
R.A.=7h. om. 17-5s., dec.=4-17° 19’ 14”. 
This is about 24° south of ¢ Geminorum, and crosses the 
meridian at about 5 p.m. 
A New Nesura.—Whilst searching for new double stars 
on January 18, the Rev. T. E. Espin discovered a nebula 
in the constellation Perseus which he believes to have 
been previously unrecorded. 
This object precedes B.D.+33°.746 by 7-80s., and is 
2! 25" south of it, so that it lies somewhere about half- 
vay between ,¢ and & Persei. It is about 6” in diameter, 
and is elongated towards the north, its brightness being 
about equal to that of a tenth-magnitude star. The later 
observations appear to suggest a planetary nebula with a 
small star on the northern edge (Monthly Notices R.A.S., 
vol. Ixvii., No. 5, March). 
Comet 1905 1V.—A further observation of comet 1905 IV. 
(1g06b) is recorded in No. 4166 (April 5) of the Astrono- 
mische Nachrichten by Prof. E. Becker, who, with the 
large refractor of the Strassburg Observatory, saw it as a 
small round body, of about the tenth magnitude, on 
March 4. The observations of this comet now cover a 
period of about 2} years. 
In the same journal Prof. Weiss gives a continuation of 
his ephemeris, extending from April 2 to June 5, which 
shows that the comet is apparently travelling very slowly 
through Libra in a north-westerly direction towards Virgo. 
Tue TEMPERATURE OF Mars.—Hitherto the chief obstacle 
to the belief that Mars is habitable by any such beings as 
inhabit the earth has been the extremely low temperature 
probably obtaining on the Martian surface, but in No. 25, 
vol. xlii. (March), of the Proceedings of the American 
Academy of Arts and Sciences, Prof. Lowell shows that, by 
taking all the phenomena into consideration, this obstacle 
may be removed. Previous calculations of the temperature 
have been ‘deduced solely from the relative distance of 
Mars from the sun, and a recent investigation gave 
—33° F. as the mean temperature of the planet. 
Prof. Lowell points out, however, that other factors, 
such as the relative albedoes of the planets, the screening 
effect of clouds, the blanketing effect of the atmosphere, 
&c., should be taken into account, and, on this basis, he 
finds that the mean annual temperature of Mars, if the 
heat were retained as well there as here, would be about 
72° F. As the retention is greater in the case of the earth, 
this value is considerably reduced in the final calculation, 
taking all the known factors into consideration, and a 
mean temperature of about 47° F. is obtained. Prof. 
Lowell also finds that the boiling point of water on Mars 
would be about rir° F. (44° C.), that the amount of air 
per unit surface is about two-ninths that found in the case 
of the earth, whilst the relative density of the air at the 
surface is only about one-twelfth. 
GALILEO IN THE VAL D’ARNO.—The April number of the 
Monthly Review contains an interesting article by Miss 
Janet Ross giving some details of Galileo’s life whilst he 
dwelt near Florence, first as court mathematician and 
philosopher, then as a prisoner at the hands of the Inquisi- 
tion. It was at a villa known as “‘ Le Selve,’’ near Signa, 
that he discovered spots on the sun and wrote his treatise 
on the planets, his history of sun-spots, and other works; 
whilst ina second villa in the neighbourhood, now known 
as the “‘ Villa dell’ Ombrellino,’’ he wrote the ‘‘ Saggia- 
tore ’’ and commenced his *‘ Dialogues on Motion.’’ After 
the persecution at Rome in 1633 he lived at Il Gioello, 
Arcetri, and it was here that the Inquisition forbade him 
io converse with anyone, so that from that date until his 
death in 1642 he was an isolated prisoner, and for the last 
NO. 1955, VOL. 75] 
cO? 
593 
four years was totally blind. Miss Ross also gives some 
interesting facts. concerning the  philosopher’s family 
affairs. 
ANoTHER New AstTRONOMICAL JOURNAL.—From the 
Societa Astronomica Italiana we have received the first 
three numbers (January, February, and March) of its 
monthly bulletin, the Revista di Astronomia e di Scienze 
affint. The society was founded by Prof. Boceardi, of the 
Turin Observatory, in November, 1906, and has for its 
principal aim ‘‘ the vulgarisation of astronomical concep- 
tions.”’ These bulletins contain original articles, 
nomical notes, and reviews, together with ephemerides and 
notes concerning celestial phenomena for the succeeding 
month, and are published by the society at Turin. 
astro- 
THe Stonyuurst CoLLeGE Oxservatory.—Father Sid- 
greaves’s report of the work done at the Stonyhurst 
Observatory during 1906 contains, in addition to some 
astronomical notes, the detailed results of the magnetic 
and meteorological observations made during the year. On 
the astronomical side, the sun was observed and drawings 
of the solar surface made on 212 days, and. the large 
grating spectrometer was employed on the larger spots. 
For this work a new heliostat is being built which will 
carry a 12-inch mirror, and when the instrument is com- 
plete it will be possible to employ the full aperture of an 
8-inch objective for use with the large Rowland grating in 
solar. spectroscopy. Good ‘spectrograms of Mira Ceti and 
some selected brighter stars were obtained during the year. 
The mean magnetic declination for 1906 was 17° 48'-3 W. 
THE TWENTIETH VEAR AT BLUE HILL 
OBSERVATORY.* 
BLUE HILL OBSERVATORY on January 30, 1905, 
completed its twentieth year’s work, and it is note- 
worthy that three out of its staff of four have been there 
at least eighteen years. Owing to the crowds of people 
brought to the hill by the electric cars, it was found 
necessary in 1905 to enclose the observatory by wall and 
fence, some of the secondary instruments having previously 
been moved for the same reason. Blue Hill is one of the 
few American observatories where the standard instru- 
ments have remained in the same position and with un- 
changed environments for so long a time, so that, except 
for the fact that the times of observation were changed 
to agree with those made by the U.S. Weather Bureau, 
the records are all strictly comparable. Since 1901 the 
observations have all been published in the metric units, 
English units being only used’ in parallel in the summaries. 
The exploration of the upper air by means of kites 
carrying instruments which recorded continuously was first 
originated at Blue Hill in 1894. In rgor the first obsery- 
ations over the North Atlantic were made by the director, 
Mr. A. L. Rotch, and Mr. Sweetland, using kites flown 
from a steamer. Kite observations are now made when- 
ever possible on the days fixed by the International Com- 
mittee for Scientific Aéronautics. These are generally the 
first Thursday in each month. In 1903, fifteen flights were 
made, nine of these being on days fixed by the committee. 
The average height reached was 2214 metres. In 1904, 
eight out of fourteen flights made were on appointed days, 
and the average height was 2300 metres. In 1905, sixteen 
days were assigned by the International Committee, and 
at Blue Hill flights were made on twelve of these and on 
four other days; the average height reached was 2120 
metres. During the three years the maximum _ height 
reached was 4468 metres, or 14,662 feet. Since 1894, 280 
flights have been made at Blue Hill. 
In September and December, 1904, and January, 1905, 
at the St. Louis Exhibition Assman balloons were liberated 
with instruments. During the summer of 1905 another 
series of ascents was executed by Mr. Fergusson. Out of 
the thirty-five balloons liberated at St. Louis, thirty-two 
have been returned, most of them with records of pressure 
and temperature. The records show that fifteen balloons 
1 Annals of the Astronomical Observatory of Harvard College. Vol 
Ivii., part ii. Observations and investigaticns made at the Blre Hill 
Meteorological Observatory, Massachusetts, U.S.A., in the years 1903 and 
1904, 
