C) 
27 
NATURE 
[Fuly 22, 1886 
inst. 
sharply cut rock of granite at its extremity. The temperature 
was 43°°2 C. in the shade, showing that the air above the sea | 
was very hot, and that the explanation of the phenomenon is to 
be found in the same causes as those determining a mirage in 
the Sahara. The lowering of the temperature was very rapid, 
falling as muchas 2° C. at Bouzarcah Observatory. The 7th 
inst. was the hottest day that has yet been felt there this season. 
Lightning struck the Government barrack at Mustapha, and 
ignited piles of hay, inflictins damage to the extent of 4000/. 
THE additions to the Zoological Society’s Gardens during the 
past week include a Khesus Monkey (Aacacus rhesus) from 
India, presented by Mr. F. W. Steward ; a Ring-tailed Lemur 
(Lemus catta) from Madagascar, presented by Mrs. Collcutt ; 
six Prairie Marmots (Cy zomys ludovictanus) from North America, 
presented by Mr. F. J. Thompson ; two Common Foxes (Canis 
vulpes) from Russia, presented by Mr. Harrison Cripps, 
F.R.C.P.; a Common Rhea (Rhea americana) from South 
America, presented by Mr. J. W. Bell; four Red-bellied 
Squirrels (Sezerws variegatus) from Trinidad, presented by Mr. 
R. J. Lichmere Guppy; two Peba Armadillos (Zatusia pea) 
from South America, presented by Mr. J. Clements ; a Greater 
Black-backed Gull (Zavus marinus), British, presented by Mr. 
Henry Stevens, M.D. ; twenty-four Sand-Lizards (Lacerta agilis), 
a Slowworm (dA xguis fragilis), a Common Snake (7rapidonotus 
natrix) from Germany, presented by Mr. S. Schaefer; two 
Sarus Cranes (Gras antigonz) from North India, eight European 
Tree Frogs (/fyla arborea) from Germany, purchased ; two 
Long-fronted Gerbilles (Gerbillus longifrens), an Elliot’s Pheasant 
(Piasianus elliott), a Bronze-winged Dove (Phafs chalcoptera), 
Cape Matifan appeared from Algiers close at hand with a | 
a Barred-shouldered Dove (Geoseltia humeralis), bred in the | 
Gardens. 
OUR ASTRONOMICAL COLUMN 
SCHULHOF’s RESEARCHES ON THE ORBIT OF COMET 1873 
VII. (CoGGiA—WINNECKE).—The elements of Comet 1873 
VIL. bear a certain resemblance to those of Comet 1818 I., which 
was observed by Pons. Prof. Weiss asserts the identity of these 
two comets, and adopts sixty-two years as the most probable 
value of the period ofrevolution. Inthe Bulletin Astronomi jue, 
tome ili. p. 125 ef seg. M. L. Schulhof has published a most 
exhaustive discussion of the orbit of Comet 1873 VIL, and has 
gone into the question of its possible identity with 1818 I., as 
well as with 1457 I. (the observations of which by Toscanelli 
have recently been discussed by Prof. Celoria) in a most 
thorough manner. The opinion which he expresses, with some 
reserve, as the result of his investigations, is that the Comets 
1873 VII. and r8r8 I. are distinct bodies with a short period of 
revolution, having a common origin. The Comet 1457 I. is 
probably identical with 1873 VIL, but it is also possible that 
the two comets, 1873 VII. and 1818 I. are fragments of 1457 L., 
which must have been a much more conspicuous object than 
either of them, to have been seen by Toscanelli and by the | 
Chinese with the naked eye. 
SOLAR ACTIVITY DURING THE First HALF oF 1886.—The | 
numbers and areas of sunspots have shown upon the whole a 
decided falling off during the past half-year as compared with 
the last six months of 1885, although no month of the present 
year has shown so low a daily average as December 1885. 
‘There has been, however, a steady increase in the number of 
days on which the sun’s disk was free from spots, one side of 
the sun being, on the average, much less spotted than the other, 
causing an apparent short period in the variation of the spotted 
area, of about a synodic rotation of the sun in duration. The 
month in which the mean daily number of sunspots was least 
was February ; that in which it was most was March. An 
exceedingly fine group was observed on May 8. 
Prominences have shown fewer fluctuations in their numbers 
and size, but have been fully one-fourth less numerous on the 
average than in 1885. 
ASTRONOMICAL PHENOMENA FOR THE 
WEEK 1886 ¥ULY 25-31 
(FOR the reckoning of time the civil day, commencing at 
Greenwich mean midnight, counting the hours on to 24, 
is here employed.) 
At Greenwich on Fuly 25 
Sun rises, 4h. 15m.; souths, 12h. 6m. 14°6s. ; sets, 19h. 57m. ; 
decl. on meridian, 19° 38' N.: Sidereal Time at Sunset, 
16h. 11m. 
Moon (one day after Last Quarter) rises, 23h. 35m.*; souths, 
6h. 39m. ; sets, 13h. 54m. ; decl. on meridian, 11° 23’ N. 
Planet Rises Souths Sets Decl. on meridian 
h. m. h. m. . m ha 4 
Mercury 6 50 13) 400. eeOud2 10, GN say 
Vienusiss heel lei 9 40 17 55 22 22 N. 
Mars 10 59 16 35 22 EI coe Sm ESS 
Jupiter... 9 47 554s een 20 I oO 32 N. 
Satum=. =) 2.43 Io 51 . 18 59 22) D5 Nee 
* Indicates that the rising is that of the preceding evening. 
Occultations of Stars by the Moon (visible at Greenwich) 
Corresponding 
angles from ver- 
July Star Mag. Disap. Reap. “tay to right for 
inverted image 
h. m. h. m. Ol 7 
27) 22: (85 qbaliniwes: 220 O 4.2, 049 go 224 
27 2; G Maur Sct, seh) ay toh Bas Ry ZG) 10 297 
27 ... oO) Laur... as. 54) --. 3) 23, Beat approachins 54am 
July h. 
25 5 ... Mercury at greatest distance from the Sun. 
28 22... Venus in conjunction with and o° 6’ south 
of « Geminorum. 
28 23 Venus in conjunction with and 3° 46’ north © 
of the Moon. 
Variable Stars 
Star R.A. Decl. 
| Ing tens yh h. m. 
U Cephei ... o 52:2... 81 16 N.... July 28, 22 51 m 
Algol 3 0'8 ... 40.31 Nis... 5, 28) saan 
»» 30, 22 36 m 
5 Libra ae SEAN SASO. cam Bde O.ar oy) gly Ske eee 
Ry SCorpliy ys. meee LOL OLOh 5.8224 OLS es mee Le iM | 
U Ophiuchi... 17 10:8 .:. 1 20 Ns 3). 27) 23,52 7 
W Sagittarii 17°57°8.... 20 35S. -c- 53, 2OymOmmummE 
B Lyre... 18: 45:9... 33 14. N.... 5, 20; 92eeOmae j 
n Aquilz . 19 46°7~.. "© 43 N...5 %; 25; summer 
5 Cephei | 22 24°90... 57 50N.... ,, 25, 21 3047 
M signifies maximum ; 7 minimum ; 7, secondary minimum. 
Meteor Showers ; 
The principal shower is that of the Aguarids, maximum — 
July 28; radiant R.A. 340°, Decl. 13° S. Other showers are as 
follows :—The Andromedes (I.), R.A. 8°, Decl. 36° N. ; near 
x Persei, R.A. 32°, Decl. 53° N. ; near 8 Urs Majoris, R-A.” 
165°, Decl. 53° N. ; and near the Pole, R.A. 300°, Decl. 87° N. 
ON LAYING THE DUST IN MINES 
eS a paper recently contributed to the South Wales Institute 
of Engineers,! Mr. Archibald Hood, the President, says :— 
““Tt was probably first suggested by Faraday and Lyell about 
the year 1845 that coal-dust was in some way inflammable. 
This idea was subsequently set forth by several French 
engineers, but all that was done previous to the year 1875 bears — 
the same relation to subsequent demonstrations as the steam- 
engine of Hero of Alexandria bears to the steam-engine of the 
nineteenth century.” 
Assuming Mr. Hood's date to mark correctly the commencement 
of the real battle between the new theory and its predecessors, 
it cannot surely be urged that the period of ten years which has 
since elapsed has been too long wherein to destroy the vast herd 
of previously existing chimeras, and to introduce and establish a 
new and different order of ideas. Doubtless the result attained 
up to the present has been prodigiously accelerated by the labours” 
of the Royal Commission on Accidents in Mines, and of the 
**<On the Watering of Dusty Mines.” 
The South Wales Institute of 
Engineers, March 18, 1886. : 
