502 
NATURE 
[Sef¢. 23, 1886 
OUR ASTRONOMICAL COLUMN 
PHOTOGRAPHIC DETERMINATIONS OF STELLAR POSITIONS. 
—Dr. B. A. Gould, in a paper presented at the Buffalo meeting 
of the American Association for the Advancement of Science 
on August 20, 1886, gives some interesting particulars with re- 
gard to his photographic work at Cordova. He states that no 
northern stirs were photozraphed there except the Pleiades and 
the Preesepe. On the Pleiades plates all but one of Bessel’s 
stars are found, which fall within the limits of the field; the 
missing one being of the magnitude 94, whilst there are depicted 
on the plates other stars of the magnitudes 10, 103, and 11. 
About seventy southern clusters have been repeatedly photo- 
graphed at Cordova, also more than a hundred double stars, 
whilst the total number of photographs which Dr. Gould has on 
hand for measurement is about 1300, only a few having been 
preserved in which the images are not circular. In addition to 
these classes of objects, special attention was given for many 
years to taking frequent impressions, at the proper seasons, of 
four stars selected, on account of their large proper motions, as 
likely to manifest appreciable annual parallax. All but one of 
these four stars—8 Hydri—have been included in the lists 
observed and discussed by Drs, Gill and Elkin at the Cape. 
Still, it will be a matter of much interest to apply the photo- 
graphic method of investigation to the same problem, even 
if for no other purpose than a comparison of the re- 
sults of the two methods. With regard to the progress 
made in the measurement of the Cordova photozraphs, Dr. 
Gould states that the measurements thus far completed are those 
of the double stars, the four stars with large prop2r motion, the 
Pleiad-s, the Praesepe, and the clusters Lacaille 4375 and 
« Crucis. The correspondinz computations have been made as 
yet only for a portion of the Pleiades plates, but it is expected 
that all these will be completed at a comparatively early 
date. The results deduced from the Pleiades photographs will 
be looked for with much interest, especially as Dr. Elkin has 
recently executed at Yale College a heliometric triangulation of 
the principal stars of the group, and the comparison of the 
results will be a severe test of the photographic method for the 
determination of stellar positions. But astronomers expect good 
work from Dr. Gould, and they are not likely to be disap- 
pointed. Dr. Gould’s paper is published in the Scientific 
American Supplement, No. 556. 
Gorr’s Nova Ortonts.—Rev. T. E. Espin announces in 
Circular No. 9 of the Liverpool Astronomical Society that, 
observing on the night of September 14, he found the Mova 
to have a magnitude of 9:2. ‘The star, he says, appeared very 
red. The small comes / was estimated as of 9°7 magnitude. 
HELIOMETRIC OBSERVATIONS OF THE PL¥IADES.— We 
learn from Science, vol. viii. No. 187, that at the recent meeting 
of the American Association Dr. Elkin communicated a paper 
upon a comparison of the places of the Pleiades ax determined 
by the Konigsberg and Yale College heliometers. The results 
given were provisional, but they show unquestioned change of 
position with reference to 7 Tauri since 1860. Most of the 
brighter stars of the group, as shown by Newcomb in _his 
“Catalogue of Standard Stars,” go with » Tauri, but among 
the smaller stars there are unquestioned departures from this 
community of proper motion. 
GouLD’s ‘‘ ASTRGNOMICAL JOURNAL.”—Our readers will be 
glad to learn that there is a prospect of the publication of this 
valuable periodical being resumed. The American Association 
at the recent meeting passed a unanimous resolution congratu- 
lating Dr. Gould on the proposed revival of the ¥owrna/, and 
expressing its best wishes for his success. 
ASTRONOMICAL PHENOMENA FOR THE 
WEEK 1886 SEPTEMBER 26—OCTOBER 2 
(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 September 26 
Sun rises, 5h. 54m. ; souths, 11h. 51m. 17°45. ; sets, r7h. 48m. ; 
decl. on meridian, 1° 19’ S.: Sidereal Time at Sunset, 
18h. tom. 
Moon (New on September 27) rises, 3h. 42m. ; souths, roh. 37m. ; 
sets, 17h. 19m. ; decl. on meridian, 7° 12’ N, 
Planet Rises Souths Sets Decl. on meridian 
h. m. h. m. m. an 
Mercury 5 42 Tid) See 1750 o 34N. 
Venus ... 4 12 FO 50 5.. 17 28 6 44N. 
_ Mars LOA 5) Sere 5 eS kee melO 2. 19 32S. 
Jupiter... 6840" 55 2e 30M ees ero 4 18S. 
Satupnse wees ee Sue Siaive- in yar XiLue ees nEnaeT 4 21 28N. 
* Indicates that the rising is that of the preceding evening. 
Sept. h. 
2ON raety, Venus in conjunction with and o° 34’ north 
of the Moon. 
287 = 3 Mercury in superior conjunction with the 
Sun. 
Variable Stars 
Star R.A. Decl. 
h, m. BO h m. 
Algol 3 08... 40 31 N. ... Sept.29, 3 43 m 
Oct. 2, © 31 m 
A Tauri 3/54°4 ... 12-10 Ni... 3) | 2 ueSeons 
¢ Geminorum 6 574... 20 44N. ... Sept. 29, 2 48 
T Geminorum 7 42:51... 24) 1 Ne a Octane AL 
6 Librze = 14/5459... 8 4S. /.-. Sept. 285) leases 
U Corone ... » 15 13°6 2.32) 4. Nii. 50 28hegneees 
U Ophiuchi... . 17 10°8 I 20\N..%. 4, 28) stomps 
21 28 m 
W Sagittarii 17. 57 :8:0ce 29) 35) 5e0es> | ys) Oe ORO 
U Sagittarii... 18 25:2"... TO) 12'S.) <.2) 4) 2s O MONA 
Oct. 1, 6 ‘oe 
R Lyrz 18 519 ... 43 48 N. ... Sept. 28, m 
S Vulpeculee NOWAR ieee jie OF Nicene ane m 
5 Cephei 22) 24:9)... 57 SON: =... Octo 2, mi 
M signifies maximum ; 7 minimum. 
Meteor Showers 
The Aurigids, R.A. 85°, Decl. 50° N., the Ayuarids, R.A, 
33, Decl. 2° S., and meteors from the following radiants have 
been obse-ved at this time :—From Musca, R.A. 46°, Decl, 26° 
N. 3; nears Aurigee, R.A. 70°, Decl. 32° N. ; and near a Cephei, 
R.A. 315°, Decl. 62° N. 
Stars with Remarkable Sp-ctra 
Name of Star R.A. 1886'0 Decl. 1886°0 Type of 
boy bry a . : spectrum 
TArietisste. eat Q2ATMG Tite ce DC WG OUNE ES IIL 
D.M. + 8° 443 2rATE Soa...) I g2eR IN ILL. 
PATIGHS) pee eee 2N AOR 230 ns aly) wy ocmeN IIL. 
a Ceti ZESORUSu 8 Sek Onsen! II. 
p Persei fe 2 57 50 38 23°9 N III. 
D.M. + 57° 702 3 240 57 28:2 N IV. 
THE BRITISH ASSOCIATION 
SECTION G 
MECHANICAL SCIENCE 
OPENING ADDRESS BY SIR JAMES N. Douctass, M.InsT.C.E., 
PRESIDENT OF THE SECTION 
. . . I propose to address you on a subject with which I have 
been practically connected for nearly half a century, that is, the 
development of lighthouses, light-vessels, buoys, and beacons, 
together with their mechanical and optical apparatus. . . . 
During the last century a very considerable increase has oc- 
curred in the number of lighthouses and light-vessels on the various 
coasts of the world, which have been requi-ed to meet the rapid 
growth of commerce. Only during the last twenty-five years 
can accurate statistical information be obtained, and it is found 
that in the year 1860 the total number of coast lights throughout 
the world did not exceed 1800, whereas the present number is 
not much less than 4000. . 5 
Concurrently with the enormous increase in the number of 
coast lights during the last fifty years, very great improvements 
have been effected from time to time in their efficiency. In 1759 
Smeaton’s lighthouse on the Eddystone was illuminated by 24 
tallow candles, weighing 31b. each. ‘The intensity of the light 
of each candle, I find, from experiments made with similar 
candles prepared for the purpose, to have been about 2°8 candle 
units each ; thus the aggregate intensity of radiant light from the 
24 candles was only about 67 candle units. No optical apparatus, 
moreover, was used for condensing the radiant light of the 
candles, and directing it to the surface of the sea. The con- 
ee 
