fULY 23; 1024] 
OUR ASTRONOMICAL COLUMN. 
Comet 1913f (DeLavan).—The following is a con- 
tinuation of the ephemeris of Delavan’s comet (1913f) 
as given by Dr. G. van Biesbroeck in Astronomische 
Nachrichten, No. 4739 :— 
R.A. (true) Decl. (true) Mag. 
hee Usa: p ee 
ilys23) 7%. 5. 39.42 FeG gs 16... 66 
ty Mes 42 19 21 24 
a ae: “ey qo 39 
oy ep as e743 eee a 8. | GG 
sg)” OE 50 29 1g 32 
=o) ieee 53 18 39 9 
AG leep eae 56 10 58 54 
Pore 5 59. 6 +38 18 44... 63 
OBSERVATIONS OF HaLLey’s Comet.—The June num- 
ber of the Astrophysical Journal (vol. xxxix., No. 5) 
contains a communication by Prof. E. E. Barnard on 
the visual observations of Halley’s comet in 1g10, 
made by him at the Yerkes Observatory. Numerous 
fine illustrations from photographs accompany the 
text. In the first instance he points out that Halley’s 
comet at its return in 1910, though a brilliant and 
interesting object to the naked eye, especially in May, 
was nevertheless a disappointment when considered 
from a photographic point of view. Photographically 
its light was relatively slow, and there were few or 
no remarkable phenomena. After mentioning the 
probable encounter of the southern branch of the tail 
with the earth on or about May 18 or 19, he directs 
attention to the presence of the double tail overlooked 
by observers in the northern hemisphere. Observa- 
tions made with the 4o-in. are next described, and 
special attention is directed to the long mass in the 
tail receding from the head. The appearance is beau- 
tifully shown in three photographs taken in June at 
Yerkes, Honolulu, and Beirut. Prof. Barnard then 
brings together all his visual observations made from 
the first to the last appearance of the comet, for he 
was determined, as he says, ‘‘to prepare as faithful 
an account as possible of its appearance to the naked 
eye for the benefit of observers at future returns,”’ 
since he was much disappointed ‘‘at the meagreness 
of the records” at its appearance in 1835, when he 
was seeking published information concerning its 
“appearance. 
REPORTS OF INDIAN OBSERVATORIES.—A recent pub- 
lication gives the report of the Director-General of 
Observatories of the Observatories of Kodaikanal, 
Madras, Bombay, and Alibag for the year 1913, and 
this includes the reports of the individual direc- 
tors. As regards Kodaikanal, Dr. G. T. Walker 
states that the output of this observatory is 
at present limited by the amount of measuring 
that can be accomplished, and this is being altered 
by the training of the new assistants. He also makes 
the important statement that when Mr. Evershed 
was in Srinagar in Kashmir in 1913 he found that the 
air there was extraordinarily good for solar and stellar 
work, and it is now being considered whether the 
observatory at Kodaikanal should be totally or partially 
removed there. The only drawback, apart from the 
question of cost, is the chief disadvantage of the small 
amount of sunshine in Januaty and February, the 
months when other solar observatories are labouring 
under disadvantages, while at Kodaikanal the seeing 
is at its best. As the chief astronomical work at the 
Madras Observatory is the determination and distribu- 
tion of time this will now be closely associated with 
the distribution of the time by the new powerful radio- 
station that is to be erected in India, forming a link 
between Aden and Singapore. The idea is for the 
radio-station to be equipped with two good clocks, and 
to send special time signals to Madras, so that the 
NO. 2334; VOL. 93] 
NATURE 
541 
clock-errors can be determined and wired back to the 
radio-station previous to the distribution of the general 
time signals. The usual routine observations were 
carried out at Bombay (Colaba and Alibag), but damp, 
and white ants, caused great anxiety regarding the 
walls for the self-registering variation instruments at 
Alibag. 
RECENT PHYSICAL INVESTIGATIONS IN 
THE NORTH ATLANTIC OCEAN. 
she recent publications summarise more or less 
thoroughly our present knowledge of the 
physical features of the waters of the North Atlantic 
Ocean. One gives an account by Dr. Fridtjof Nansen 
of recent researches carried on especially by the Nor- 
wegians, and the other, by Prof. Otto Pettersson and 
Commander C. F. Drechsel, urges united international 
effort to carry on further research in these waters. 
Dr. Nansen gives a detailed account of oceano- 
graphical investigations in the north-eastern part of 
the North Atlantic Ocean made in July, 1910, on 
board the Norwegian gunboat, Frithjof, under the 
command of Capt. Caspar S. Erlandsen. 
Dr. B. Helland-Hansen and Dr. Nansen had noted 
that ‘‘variations in the temperature of the Atlantic 
current from one year to another, were followed by 
corresponding variations in the winter climate of 
Norway, and alse by variations in the fisheries of the 
North Sea and at Lofoten, etc.”” The question was 
as to whether the observed annual variations in the 
volume and temperature of what Dr. Nansen terms 
the Norwegian Atlantic current ‘‘‘ were due to varia- 
tions in the physical conditions of the North Atlantic, 
south of the Wyville Thomson Ridge and the Faeroe- 
Iceland Ridge, or to other causes, e.g. variations in 
the East Icelandic Arctic current.” 
The cruise of the Frithjof lasted fifteen days, leav- 
ing Belfast on July 6, 1910, Seydis Fiord, Iceland, 
was reached on July 13, and Bergen on July 21. On 
the basis of these observations, which are duly tabu- 
lated, five sections have been drawn. These observa- 
tions were taken with carefully selected instruments 
supplied by Dr. Nansen. The automatic insulating 
water-bottle seems to have been at times untrust- 
worthy, but otherwise the instruments gave satisfac- 
tory results. Dr. Nansen suggests that it is very desirable 
always to use two thermometers for the determination 
of deep-sea temperatures. All water samples were 
collected in rubber washered bottles with lever fasten- 
ing, holding 200 c.c. and 500 c.c. each. Titrations 
were carried out by Dr. Helland-Hansen, or under his 
supervision at Bergen. The titrations were checked 
in the ordinary way by ‘‘normal water’? from the 
International Bureau in Copenhagen. 
The observations made resulted in showing that 
vertical convection currents reached depths of 600 
metres. Dr. Nansen is of opinion that this vertical 
circulation is of great importance in heating the atmo- 
sphere of this region during the winter. It was 
estimated that direct absorption of heat from the 
sun’s rays may be felt to a depth of too metres. 
In the region traversed by the Frithjof precipitation 
is greater than evaporation, not only in winter, but 
evidently also on the average during summer. From 
the observations of Mr. Donald J. Mathews, as well 
as those of the Frithjof, it appears that in this region 
the sea-surface has its maximum salinity at the end 
of the winter or in the spring, and its minimum 
salinity at the end of the summer or in the autumn. 
Prof. Martin Knudsen has found similar seasonal 
variations. Knudsen suggests that the most probable 
1 (1) ““ The Waters of the North-eastera North Atlantic.” By Fridtjot 
Nansen. 
(2) “‘ Mémoire sur des Recherches dans 1’Atlantique avec programme 
By O. Pettersson and C. F. Drechsel. 
