Sept. 16, 1886] 
communicated to the Royal Society a description of his re- 
flecting octant; and, after some hesitation, Halley declared 
himself satisfied that Hadley’s idea was quite different 
from that of Newton, who had invented an instrument 
founded on the same principle. It is no doubt true 
that Thomas Godfrey, a glazier of Philadelphia, had in- 
vented an instrument of this kind about the year 1730; 
but the first intelligence of his invention did not reach Eng- 
land before the month of May 1732, in a letter from James 
Logan to Halley. Godfrey’s instrument was made of wood by 
Edmund Woolley, a carpenter, about November 1730, and had 
been tried on board the ship 7y2man, of which John Cox was 
master. The first model of Hadley’s octant had, however, been 
constructed by his brother George about the middle of the 
summer of 1730. The thanks of those interested in the history 
_ of astronomy are due to Dr. Dreyer for the effort which he has 
made to correct the errors on this point which are found in 
Poggendorff’s ‘‘ Biographisch literarisches Handworterbuch,” in 
Wolf’s ‘‘ Geschichte der Astronomie,” and elsewhere. 
ASTRONOMICAL PHENOMENA FOR THE 
WEEK 1886 SEPTEMBER 19-25 
JESS 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 19 
Sun rises, 5h. 43m. ; souths, rrh. 53m. 4277s. ; sets, 18h. 5m. ; 
decl. on meridian, 1° 25’ N.: Sidereal Time at Sunset, 
17h. 59m. 
Moon (at Last Quarter September 21) rises, 20h. 39m.* ; souths, 
4h. 7m.; sets, 1th. 44m. ; decl. on meridian, 15° 12’ N. 
Planet Rises South: Sets Decl. on meridian 
ib tah h. m. h. m. , 
Mercury 455 THE 20) eer LS) 3 6 oN 
Venus ... 3 50 10/45)... 17 40 9 56N. 
Mars’... ... 10 44 T5eDe ee LO! 38 18 12S. 
Jupiter... MT tL 2 2 LOS 7 3 43S. 
BciiEnerin... 23) 34% --.. 9737 2: 15) 40 21 32N 
* Indicates that the rising is that of the preceding evening. 
Occultations of Stars by the Moon (visible at Greenwich) 
Corresponding 
angles ‘rom ver- 
Sept. Star Mag. Disap. Reap. feicowmieHitcre 
inverted image 
i h. m. h, m. a a 
PeeersOy Nari... 2.916) ... 23 34... © 30f 68 229 
Bier 2OGeminormim:.. 54... 22 46... 2326 ... 23) 273 
Poe b.A.C. 3345 ... 6 53 2 41 61 206 
+ Occurs on the following morning. 
Sept. h. 
| 22... 12 ... Saturn in conjunction with and 3° 20’ north 
of the Moon. 
| 23 — ... Sun in equator. 
| Variable Stars 
Star R.A. Decl. 
h m. Ce: h. m. 
WGephei ... ... O 522... 81 16 N....Sept. 21, 19 4 2 
GGeminorum ... 6 57'4... 20 44N. i 245, 0 57, 0G 
U Monocerotis Gf res, 1) SOS Bao eg E25 M 
U Cancri POW 2 OL 3\-<-1O UL UNu sea) i959, 0255 uM 
6 Librze MAW SACO) .2s, (Oo) ANS gy 20S, Quine 
PeSoroncee-c) es. U5) 139-61... 32 4 Ni... 5, 22, T 45 
U Ophiuchi... EZ LOLS)...  L 2OUN. <-- 55, 22 4u 27772 
j and at intervals of 20 8 
(1 i 18 45°9 ... 33 14N. ... Sept. 18, 21 30 
io) 225m 2LOnrE 
nm Aquile ... 19 46°7 ORABUNG =e ss 2550 SE OnTz 
PRC VCOUE i  ..- 20 3:1 ...57 40.N. ... 55 24; M 
WeSyeuMeeey =, 20) 16% 147 32. N;.., 55 20, Ma 
Pee pocigmermacs | 20090145108 2 Ne si. j5. 205 m 
Pe@epheie.. <.. 22 24°9...57 50.N..... 5, 22,22 OF 
M signifies maximum ; #7 minimum. 
NATURE 
491 
Meteor Showers 
The following are amongst the showers of the period :—Near 
6 Cassiopeiz, R.A. 14°, Decl. 50° N. ; near a Arietis, R.A. 31°, 
Decl. 18°; and near Polaris, R.A. 68°, Decl. 87° N. 
UNIVERSITY AND EDUCATIONAL 
INTELLIGENCE 
UNIVERSITY COLLEGE, LONDON.—We notice from the 
prospectus of the Engineering Department that the examination 
for the Gilchrist (Entrance) /:ngineering Scholarship of 357. per 
annum is to be held on the 28th and 29th inst. Candidates 
must be under nineteen, and the subjects of examination are : 
—(1) Mathematics ; (2) any two or more of the following—(a) 
mechanics, (4) mechanical drawing, (c) examination on some 
subject connected with engineering, (¢) French or German, (e) 
the use of tools. The examination is intended to be of such a 
standard as can be passed by lads from school who have begun 
to acquire some knowledge of mechanical pursuits. The appli- 
ances of the engineering laboratory (under Prof. Alexander B. 
W. Kennedy) have been very much extended during the past 
year, mainly through a grant from the Gilchrist Trustees, and 
are now very complete in the direction both of experiments in 
elasticity and the strength of materials, and in the economic work 
of engines and boilers. Laboratory work is so arranged that 
students go through a systematic course of experimental instruc- 
tion in these and other connected subjects during the session. 
SOCIETIES AND ACADEMIES 
PARIS 
Academy of Sciences, September 6.—M. Emile Blanchard 
in the chair.—On presenting to the Academy a copy of a 
volume issued on the occasion of M. Chevreul’s centenary, 
August 31, 1886, M. Berthelot remarked that this seemed a 
suitable occasion for reviving the old custom of celebrating 
Academic solemnities by the publication of special scientific and 
literary essays. The present work, in the preparation of which 
MM. Ch. Richet, G. Pouchet, E. Grimaux, E. Gautier, 
Dujardin-Beaumetz, E. Demarcay, and Berthelot had co-oper- 
ated, has been executed with rare taste and care by the editor, 
M. Alcan, and by him dedicated to M. Chevreul on behalf of 
himself and his fellow-contributors.—Fluorescence of the com- 
pounds of manganese subjected to electric effluvium in vacuum, 
by M. Lecoqg de Boisbaudran. In the experiments here de- 
scribed the author has aimed especially at determining the 
effects due to the presence of manganese. The fluorescence of 
some of its compounds is an extremely sensitive reaction, by 
means of which imponderable traces of this metal may be de- 
tected in natural or artificial substances that might otherwise be 
supposed free from its presence.—Paralytic ataxy of the heart, 
by M. Mariano Semmola. In this communication the author 
resumes the results of his further observations on cardiac dis- 
orders, already reported in the 7yaxsactions of the International 
Medical Congress, seventh session, London, August 1881.— 
Remarks in connection with three Italian essays submitted to 
the Academy, by M. Govi. The first of these papers deals with 
an episode in the life of Galileo, showing that the hostility of the 
Jesuits to the Florentine philosopher was not due to the letter ad- 
dressed by him to his brother in 1606, announcing the expulsion 
of the Order from Venice. The second describes a curious 
plano-convex lens executed by Torricelli some time between 
1644 and 1647, and recently discovered in the Cabinet of Physics 
attached to the University of Naples. The third refers to an 
unpublished letter written by Volta in 1785 on Lavoisier’s pneu- 
matic theory, which, although not accepted without reservations, 
is defended against the assumptions of an Englishman named 
Lubbock, who had essayed to transform oxygen into a new 
principle called by him the ‘‘sorbile principle.”—On certain 
differential equations of the first order, by M. Roger Liouville. 
It is shown that the differential equation— 
VY + QS + 3a27" + 3% + ay=0, 
is reducible to the quadratures if its coefficients a,,...@, and their 
derivatives a’,,... satisfy the equation— 
6 
a,l! + KL 3[a', + 3(a,? - aa, =o, 
where Z represents the combination 
LZ = ana’, — aya'y + ay (4a, — Ang) + 2a9 (aq? — 2403, 
and X an arbitrary constant which may vanish.—Note on the 
