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APRIL 25, 1912] 
NATURE 
199 
for several minutes about 5 p.m. of the same day. 
White’s earliest date for the cuckoo is April 7. 
The first Sulphur butterfly and a Peacock butterfly 
were seen at the same place on April 6. As is well 
known, the brimstone or sulphur butterfly is one of 
the earliest to make its appearance, and may some- 
times be seen on a fine day in winter months; while 
Peacock butterflies which have hibernated are not 
infrequently seen in early spring. 
THERE exists in France a technical committee the 
object of which is to study and extend the knowledge 
of the means of prevention and of extinction of fire, 
and of averting accidents. It is a voluntary organisa- 
tion supported by public bodies, and includes amongst 
its members many well-known French officials. We 
have received from the committee two bulletins, one 
relating to the precautions to be taken against fire 
and accidents at exhibitions, the other to precautions 
against fire in villages. Both documents bear 
evidence of the thoroughness of the work done by 
the committee, and can be obtained for a few pence. 
We notice that in neither case does the com- 
mittee advise the provision of ‘‘extinguishers’’ or 
“‘orenades,”’ but insists on simple buckets of water. 
The headquarters of the committee are at 45 Avenue 
Trudaine, Paris. 
THE magnetic survey of Egypt, commenced in 1908, 
has been completed, and the results obtained at 
eighty-one stations are summarised in a pamphlet 
issued by the Survey Department. The field work 
has been carried out by Messrs. H. E. Hurst and 
C. B. Middleton with instruments standardised at the 
HelwAn Observatory. In the delta the declination 
varies from 3° west in the west to 2° 30’ west in the 
east, the dip from 43° in the north to 40° 30’ in the 
south, and the horizontal intensity from 0-294 in the 
north to 0-302 in the south. In Upper Egypt the 
limits are nearly the same for the declination, but the 
dip decreases to 30° 36’ and the horizontal intensity 
increases to 0-325 in the south. 
tion is 4° in the west and 2° 42’ in the east; the dip 
decreases to 26° 32’ at Wadi Halfa, where the hori- 
zontal intensity is 0-328. Values for the western 
desert are also given, and when the present survey of 
the Sudan is completed a full report covering the 
whole country is to be issued. 
Mr. STEPHEN Pacet, secretary of the Research 
Defence Association, has written a book summarising 
in ten chapters the evidence given before the Royal 
Commission on Vivisection, as well as the Inspector’s 
Report for 1910, and giving in a final chapter a brief 
account of the commission’s report. The volume will 
be published by Mr. H. K. Lewis. 
Messrs. WITHERBY AND Co. will shortly publish ‘tA 
Hand-list of British Birds,”’ giving a detailed account 
of the distribution of each bird in the British Isles 
and a general account of its range abroad, together 
with details of the occurrences of rarities. The hand- 
list is the joint work of Messrs. E. Hartert, F. C. R. 
Jourdain, N. F. Ticehurst, and H. F. Witherby. 
Messrs. Jack announce that among the volumes 
to be included in the second dozen of ‘“‘The People’s 
NO. 2217, VOL. 89| 
In Nubia the declina- | 
Books,’’ which are to be issued on May 15, will be 
“The Foundations of Science,” by Mr. W. C. D. 
Whetham, F.R.S.; “Inorganic Chemistry,” by Prof. 
E. @. G3} Baly, F:R.S.; ‘ Radiation,” bya Drees 
Phillips; ‘‘Lord Kelvin,” by Dr. A. Russell; 
“Huxley,” by Prof. G. Leighton; and “ Francis 
Bacon,” by Prof. A. R. Skemp. 
OUR ASTRONOMICAL COLUMN. 
ComeEtary Statistics.—Some interesting figures 
concerning comets have been educed by M. Borrelly, 
and appear in Nos. 51-52 of the Gazette Astronomique. 
| For 376 comets discovered since the sixteenth century 
| with 16, 15, 14, 12, and 12 respectively. 
he gives the place of discovery, Marseilles heading 
the list with 64, Paris coming second with 46, and 
Geneva, Florence, Lick, Nice, and Berlin following 
It is note- 
worthy that of British observatories, Slough is top 
with seven discoveries, and Bristol, twenty-second in 
the complete list, has four to its credit. Nearly two- 
thirds of the comets discussed were discovered in the 
morning before sunrise, and the second half of the 
year has proved more prolific in cometary discoveries 
than the first. Of these 376 comets, 106 were periodic 
and 19 have been observed at more than one return: 
only 56 have been visible to the naked eye, and seven 
could be seen during full daylight. 
Tue Best VALUE OF THE SOLaR Constant.—In the 
current number of the Astrophysical Journal (vol. 
xxxv., No. 2, March) Messrs. Abbot and Fowle 
traverse Prof. Very’s criticism of their determination 
of the solar constant noted in this column on January 
18. Among other things they deprecate the deduction 
of a value for the constant from such unknown and 
fragmentary data as the reflection and emission of the 
earth, the moon, and Mars, the temperatures of the 
two latter, and the dependence of terrestrial tempera- 
ture on insolation. They maintain that many other 
variables beside the insolation, e.g. cloudiness, dis- 
tribution of land and water, mountains, &c., con- 
siderably complicate terrestrial temperatures, and 
show that they have not departed from Langley’s 
methods except in so far as they are improved by 
thirty years’ extra experience. 
OBSERVATIONS OF SATURN AND ITs’ Rincs.—To 
No. 4566 of the Astronomische Nachrichten Dr. H. E. 
Lau contributes a note describing his observations 
of Saturn, with the ro-inch refractor of the Urania 
Observatory, during the years 1908-1910. He found 
the colour of the south pole to be bluish-green chang- 
ing to a brownish-green at a little distance from 
the actual polar region. For the various rifts he 
records various shades of colour and also places on 
record the appearance of whitish cloud masses in the 
equatorial zones in December, 1909, and September, 
1910. Measures of the rings on seven evenings in 
1909 and 1910 gave 40:03" for the outer diameter 
of the A ring, 34°59” for the Cassini division, 
26°48" for the inner diameter of the B ring, and 
21°34” for the inner diameter of the C ring; the 
breadth of the Cassini division was found to be 0:71". 
Differences of colour between the different parts of 
the various rings are also recorded. 
THE CANON Diasto Crater.—An interesting paper 
by Mr. Elihu Thomson appears in No. 109, vol. xlvii., 
of the Proceedings of the American Academy of Arts 
and Sciences, in which the author, having visited 
the famous Coon Butte or ‘‘ Meteor Crater,’’ speculates 
as to the probability of the crater having been pro- 
duced by the impact of an enormous meteor. He 
states that the amount of rock blown out of the 
cavity could not have been less than two or three 
