208 
been very largely increased during the year, the most notable 
item being a consignment of specimens from Sarawak, presented 
by Mr. R. Shelford. 
THE results of a redetermination of the atomic weight of 
uranium by Prof. T. W. Richards and Mr. Merigold are 
published in a recent number of the Proceedings of the 
American Academy of Arts and Sciences, Of previous 
determinations the only one worthy of serious consideration 
is that of Zimmermann, who in 1886 found the value 239°59. 
Zimmermann’s method, based on the preparation of pure 
UO, and its conversion into U,O,, appears likely to give 
too high numbers, owing to the difficulty of obtaining 
the lower oxide free from occluded gases and also of 
oxidising it completely. After much preliminary work and a 
long search for suitable substances, Messrs. Richards and 
Merigold chose the analysis of uranous bromide as the basis of 
their method. The preparation of pure uranous bromide and 
its manipulation present considerable difficulties. Its analysis 
was effected by first oxidising it to uranyl bromide by means of 
hydrogen peroxide and then precipitating the bromine by means 
of silver nitrate. The results showed satisfactory concordance, 
and led to a conclusion expressed by the authors as follows :— 
“If oxygen be taken as 16'000 and bromine as 79°955, the 
atomic weight of uranium appears to be not far from 238°53.” 
It is remarked that, although this number differs by more than 
a unit from that given by Zimmermann, the percentage difference 
(0°45) is smaller than many which have often been passed un- 
heeded in the case of elements of smaller atomic weight. It is, 
however, a noteworthy difference, and the probability seems 
to be that Zimmermann’s number was too high. The paper of 
Messrs, Richards and Merigold brings to light many interesting 
facts about the chemistry of uranium, 
THE additions to the Zoological Society’s Gardens during the 
past week include a Chacma Baboon (Cyzocephalus porcarius) 
from South Africa, presented by Mr. E. G. Williams ; a Patas 
Monkey (Cercopithecus patas) from West Africa, presented by 
the Rev. E. Millar ; a Green Monkey (Cercopithecus callitrichus) 
from West Africa, presented by Mr. W. S. Hewitt; a Serval 
(Felis serval) from Africa, presented by Mr. P. Hayton; a 
Ground Hornbill (Azcorvus, sp. inc.) from South Africa, 
presented by Mr. F. H. O. Wilson; a Senegal Turtle Dove 
(Zurtur senegalensis) from West Africa, a White-fronted Dove 
(Leptopiila jamaicensis) from Jamaica, presented by Mr. D 
Seth Smith ; a Barn Owl (S¢v#x flammea) European, presented 
by Mr. G. Dundas ; two West African Pythons (Python sebae) 
from West Africa, presented by Lieut. Lamprey ; a Long-nosed 
Crocodile (Cyrocodilus cataphractus) from West Africa, presented 
by Capt. Gibson; an Orang-outang (S?mza satyrus) from 
Borneo, an Alpine Chamois (Xupzcapra tragus) from Savoy, a 
Suricate (Suricata tetradactyla), four Cape Crowned Cranes 
(Balearica regulorum) from South Africa, two Grey Ichneumons 
(Herpestes griseus) from India, deposited ; a Chimpanzee 
(Anthropopithecus troglodytes) from West Africa, purchased. 
OUR ASTRONOMICAL COLUMN. 
ASTRONOMICAL OCCURRENCES IN JULY :— 
July 2. 6h.27m. to1th. 22m. Transit of Jupiter’s Sat. IV. 
2. 4h, 3m. to 14h. 52m. Moon occults 6° Tauri 
(mag. 4°2). 
14. Minor planet Vesta in opposition to the sun. 
15. Venus. Illuminated disc = 0°807. Mars = 0'979. 
15. 10h. Mercury in conjunction with Neptune. Mercury 
I” 34'S. 
15. 15h. Mercury at greatest elongation 20° 35’ W. 
17. 13h. Saturn in opposition to the sun. 
18. $h. 51m. to 12h. 34m. ‘Transit of Jupiter’s Sat. III. 
19. Saturn. Outer minor axis of outer ring = 16/°38. 
NO. 1704, VOL. 66] 
NATURE 
[JUNE 26, 1902 
July 19. 10h, 56m. Minimum of Algol (8 Persei). 
19. 10h, 58m. to1th. 54m. Moon occults p! Sagittarii 
(mag. 3°9). 
23. 14h. Mars in conjunction with Neptune. Mars 
ees 7/aIN 
25, 12h. 9m. to 15h. 51m. Transit of Jupiter's Sat. III. 
Zyem7 he Venus in conjunction with Neptune. Venus 
On x1’ N. 
28. 14h. Venus in conjunction with « Geminorum, Venus 
(oy SE 
28-30. Epoch _ of the Aquarid meteoric shower (radiant 
339-11). 
30. 14h. 46m. to 15h. 28m. Moon occults # Tauri 
(mag. 5°I). t ’ : 
31. 2th. Venus in conjunction with Mars, Venus 
ToTOeSs 
THE ANNA BREDIKHINE ASTRONOMICAL PRIzE,—The 
conditions of this new astronomical prize, founded by Prof. 
Th. Bredikhine in memory of his wife, are published in Zhe 
Observatory for May. The prize is to be awarded for the most 
thorough investigations of any large comet, the investigations to 
be pursued on the lines followed by the donor in his own famous 
cometary researches. 
OccULTATION OF W LEonis.—Mr. J. F. Cole, of Cam- 
bridge, Mass., writing to Popular Astronomy (June, 1902), notes 
an observed decrease in the magnitude of this variable double 
about one half-second before its occultation. He suggests that 
other observers might endeavour to discern the probable change 
of colour at the next occultation, which takes place at gh. 21m. 
(Washington mean time) on July 7, magnitude 5°6, position 
angle 99°. 
A REMARKABLE ROLIDE OBSERVED AT LYONS ON MARCH 
19.—A correspondent of the Société Astronomique de France 
records the appearance of ‘‘a magnificent bolide” at 9.10 p.m. 
on March 19. The observer, who was situated at Lyons, states 
that the meteor first appeared in the neighbourhood of Arcturus 
and then travelled eastwards until lost in the haze on the horizon. 
Form, round; light, yellowish orange; magnitude, brighter 
than eos H trail; none; duration, 2 seconds (Bulletin de la 
Soctété Astronomique de France). 
Rerhcion OF VARIABLE: STARS.—At the suggestion of 
Mr. A. Stanley Williams, and with the idea of correlating the 
various notations, a list of eighty-one variables to which 
different names have been assigned in published lists of variable 
stars, has been prepared by Mr. H. C. Wilson and published in 
this month’s Popular Astronomy. 
Of the various systems of notation in vogue, Mr. Wilson 
favours that used in the Azzzzzaire, where the first nine variables 
discovered in a constellation are named by the last nine letters 
of the alphabet in their normal sequence ; the second nine 
variables discovered in that constellation are designated in the 
same way, but the suffix ‘‘2” is added to the capital letter, 
and so on for the third, fourth, &c., sets of nine. Thus the 
twentieth variable discovered in Sagittarius is catalogued as 
S3 Sagittarii. As the author remarks, ‘‘ This method is capable 
of indefinite extension without becoming cumbersome ; but, 
unfortunately, it does not have the advantage of priority, nor of 
adoption by those who are doing the most valuable variable-star 
work,” and he therefore suggests that the double-letter system, as 
adopted by the Variable Star Committee of the Astronomische 
Gesellschaft, should be universally used ; further, he suggests 
that the assignment of the notation to individual stars should be 
left entirely to the Committee, and, for provisional purposes, he 
advocates the adoption of the notation now used in the 
Nachrichten when naming newly suspected variables, viz. to 
assign consecutive numbers and to add the year of discovery, 
e.g. 3, 1901. 
STUDY OF BRIGHT POINTS AND CURVES. 
‘THE study of ‘‘ brilliant points and lines” is an application 
of the principles of geometrical optics which has not 
hitherto received the amount of consideration which it deserves, 
when account is taken of (1) the simplicity of the principles in- 
volved, (2) the elegance of the resulis obtained, and (3) the 
ease with which the subject can be studied experimentally, The 
writer of the present note has a dim recollection of having 
worked out in his undergraduate days a tripos rider in which it 
was required to find the equation of the bright curves seen 
