i JuLy 4, 1912] 
the moulds were being erected. Chimney flues and 
other stoneware pipes were enclosed in the moulds 
and embedded in the concrete subsequently poured in. 
The mould consisted of some 2600 castings of size 
and weight convenient for handling, and assembled 
by about 10,000 bolts and nuts; the erection of the 
mould occupied about eight days, pouring about six 
hours, followed by two days’ rest; removal of the 
mould occupied two days, making thirteen days in 
all for construction. Colloidal material is added to 
the concrete in order to avoid segregation and to 
facilitate its flow to all parts of the mould. 
A usegFuL bibliography of the papers and records 
published with respect to the geology and palzon- 
tology of the north of England (Yorkshire excepted) 
during 1910 was contributed by Mr. Thomas Sheppard 
to The Naturalist in May and June of this year. The 
bibliography has now been issued in pamphlet form 
by Messrs. A. Brown and Sons, Ltd., of London, 
Hull, and York. 
Mr. Francis Epwarps, of High Street, Marylebone, 
London, W., has issued a catalogue of books relating 
to Australasia, which he is offering for sale. The 
books include some important volumes on the Ant- 
arctic. 
ErratumM.—In Nature of June 27, 
line a1, for 894 miles read 63; miles. 
D8 426, col. 2, 
OUR ASTRONOMICAL COLUMN. 
ASTRONOMICAL OCCURRENCES FOR JULY: 
July 4. 12h. om. The Sun at greatest distance from 
Earth. 
5. 14h. om. Venus in superior conjunction 
with the Sun. 
io. 16h. 13m. Saturn in conjunction with the 
Moon (Saturn 5° 36! S.). 
13. 8h. 31m. Venus in conjunction with Nep- 
tune (Venus 1° 27! N.). 
14. 2h. 29m. Neptune in conjunction with the 
Moon (Neptune 5° 34! S.). 
;» 3h. 58m. Venus in conjunction with the 
Moon (Venus 4° 6! S.). 
15. «7h. 24m. Mercury in conjunction with the 
Moon (Mecury 3° 57!’ S.). 
» 23h. om. Neptune in conjunction with the 
Sun. 
16. 12h. 9m. Mars in conjunction with the 
Moon (Mars 2° 46! S.). 
22. th. om. Venus in perihelion. 
23. 8h. 12m. Jupiter in conjunction with the 
Moon (Jupiter 4° 36’ N.). 
24. 7h. om. Uranus at opposition to the Sun. 
25. 3h. om. Mercury at greatest elongation E. 
of the Sun. 
28. sh. 45m. Uranus in conjunction with the 
Moon (Uranus 4° 21! N.). 
29. toh. om. Mercury at greatest distance from 
the Sun. 
THE Nova or VarIABLe 87, 1911, PeRsEI.—On April 
3 Prof. Wolf gave an hour’s exposure, with the re- 
flector, on the region of the nova, or variable star 87, 
1911, Persei, discovered by Mr. C. R. D’Esterre, and 
the photograph is reproduced, together with Mr. 
D’Esterre’s plate of November 13, 1911, for com- 
parison, in No. 4585 of the Astronomische Nachrichten. 
On Prof. Wolf’s plate the nova(?) is very faint, 
NO. 2227, VoL. 89] 
NATURE 
459 
| while on the earlier plate it is comparable in bright- 
ness with two of the brightest stars seen on both 
photographs. Practically identical with the position 
of the nova(?) there is a faint pair of stars, the more 
northerly of which Prof. Wolf shows to be variable, so 
the region is evidently one of exceptional interest. 
PERSEIDS IN AuGUST, I911.—Simultaneous observa- 
| tions of meteors were made by Herren Biiss and 
Djukow at Dorpat and Elwa respectively, on August 
g-12, 1911; Elwa is not very far west of Dorpat. 
The results are tabulated in No. 4582 of the Astro- 
nomische Nachrichten, and embody the observed paths 
of 122 meteors observed at the former and 31 observed 
at the latter station. The maximum took place on 
August 12, and some of the observed paths were 
curved or wavy; there was a tendency also, noted on 
previous occasions, for the Perseids to appear in pairs 
travelling along parallel paths. A number of radiants 
were determined, the mean position being «=44'5°, 
5=+565. Nine meteors were recognised in both 
records, and the heights of the appearance and dis- 
appearance were calculated; these range from 405 to 
103°6, and from 30°5 to 1o1’0 kms. respectively. 
OssERVERS’ HanpBooK.—We have received the first 
fascicule of a work by M. G. Raymond, entitled ‘‘ Les 
Merveilles du Monde Sidéral,’”’ in which the author 
gives brief descriptions and positions of the interest- 
ing celestial objects found in the first six hours of 
right ascension. The book reminds one of the ‘‘ Celes- 
tial Objects,” only that the author has arranged the 
double stars, nebula, &c., under single hours of right 
ascension, giving the constellations in each hour in 
alphabetical order; thus, for example, the especially 
interesting objects in the constellation Andromeda are 
found in six different parts of the book under oh., 
th., 2h., 2th., 22h., and 23h. The positions are 
given to the nearest minute for 1910, and amateur 
observers should find the work most useful; it is 
published by G. Thomas, 11 rue du Sommerard, 
Paris, at 4 frances for the one part. 
VARIABLE STARS OF SPECIAL INTEREST.—The light- 
variations of twenty-five variable stars in the Small 
Magellanic Cloud are discussed by Miss Leavitt in 
Circular 173 of the Harvard College Observatory. A 
previous investigation indicated that there existed a 
relation between the brightness of these variables and 
the length of their periods, and this is confirmed in 
| the present study; the logarithm of the period (in 
days) increases by about 0°48 for each increase of one 
| magnitude in brightness. As the distances from the 
earth are presumably alike, it would appear that the 
period is associated with the actual emission of light 
determined by the physical conditions of the stars. The 
average range of brightness is about 12 magnitudes, 
| and the periods range from 12 to 127 days. 
Circular No. 171 contains the data for the light- 
curves of five variable stars having secondary minima. 
One of these, RT Persei, appears to be an Algol 
variable, and the other four, RV Ophiuchi, V_ Ser- 
pentis, RZ Draconis, and U Scuti, are of the 8 Lyrz 
type. 
SEARCH-EPHEMERIDES FOR Comets.—In No. 4577 of 
the Astronomische Nachrichten Dr. Hnatek publishes 
ten search-ephemerides for comet 1852 IV. (West- 
phal); the periods on which the ephemerides are re- 
spectively based range from 60'2 to 610 years, increas- 
ing in steps of o'1 year. The comet is far south, and 
is not likely to be found during the present year. 
Dr. H. J. Zwiers has calculated elements for 
Holmes’s comet, based on the observations of 1906, 
and in No. 4584 of the same journal he gives an 
ephemeris for June and July. The comet is unfavour- 
| ably placed, and is not observable in these latitudes. 
