NATURE 
315 
White- and red-hot metallic neutral bodies exercise this dis- 
ing power even when isolated from the earth, but always 
with less facility than when earth-connected. 
The hotter the discharging body, whether isolated or earth- 
connected, the more nearly alike do + or—electricities behave 
in being discharged ; but at certain temperatures distinct differ- 
ences are noticed. The —electricity, in all cases of difference, 
is discharged with greater facility than the +. 
Attempts are made to measure the critical temperatures at 
which earth-connected hot iron (1) discharges + and — electricity 
with nearly the same facility, (2) begins, as it cools, to showa 
preferential power of discharging —, and (3) ceases to discharge 
—. The temperatures so obtained are measured by the number 
of heat-units, measured from o° C. in I . Of iron of the 
respective temperature, represented by the value of the expres- 
sion Fe ,w. 
It is shown that various flames, both earth-connected and 
isolated, have an exceedingly great power of discharging both 
kinds of electricity. 
The effects in regard to discharge are shown to be similar 
when platinum wire, rendered hot by a galvanic current, is used, 
and also when the condensed electricity of a Leyden jar is ex- 
-perimented on, q : 
As hot iron shows a preferential power of discharging — over 
+ electricity, so it is found that white-hot but isolated iron 
refuses to be charged either with + or—electricity. As the 
iron cools it acquires first the power of receiving — and after- 
wards of receiving +. Further, while white-hot iron in contact 
with an electrified body prevents that body from retaining a 
charge of either kind of electricity, as it cools it permits a + 
charge to be received, and subsequently a — one. 
A suggestion is made as to the existence of an electrical co- 
ercitive force, the presence of which, together with its diminu- 
tion by heat would explain much of what has been described. 
“On Curvature and Orthogonal Surfaces.” By A. Cayley, 
F.R.S., Sadlerian Professor of Mathematics in the University of 
Cambridge. 
Entomological Society.—lebruary “Stem W. Bates, 
vice-president, in the chair.—Mr. F. Smith exhibited a 
box of Hymenoptera, collected near Calcutta, contain- 
ing, amongst other insects, a new species of Asvafa, and four or 
five beautiful species of the genus Vomia.—Mr. McLachlan ex- 
hibited a quadrangular case formed by the larva of a trichopterous 
insect, taken by the Rev. A. E. Eaton in the river Dove in 
Derbyshire.—Mr. Champion exhibited specimens of a large 
species of Pu/ex found in a mouse’s nest in Sheppy.—Mr. Mel- 
dola exhibited a living specimen of a myriapod of the genus 
Spirobolus, sent to him from San Francisco, Also eggs of a leaf 
insect from Java (Phiyllium pulchrifolium).—Mr. Miller made 
remarks on pouch galls found on the leaves of cinnamon from 
Bombay.—Rev. Mr. Eaton read a paper on the Hydroptilide, a 
trichopterous family.—Mr. A. G. Butler communicated a mono- 
graph of the genus Gasteracantha, or crab-spiders, 
Royal Microscopical Society, Feb. 5, Anniversary Meeting. 
—W. Kitchen Parker, F.R.S.,in the chair. The report and 
treasurer’s statement of account having been presented the 
president read a highly interesting address descriptive of his 
own further researches upon cranial development, which, during 
the year, had been chiefly confined to the formation of the 
skull of the pig. He briefly indicated the methods adopted, 
and some of the results obtained, and concluded by expressing 
the opinion that what he had already observed led him to 
conclude that if all existing forms had been really derived from 
one, the process must have been slow indeed. The report 
having been adopted, and some ciscussion having taken place 
as to the society's position, cordial votes of thanks to the 
retiring president, hon. secretary, and to the other officers of 
the society for their services during the past year were unani- 
mously carried. The following is a list of the officers and 
council for the ensuing year :—President--Charles Brooke, M.A., 
F.R.S. Vice-Presidents—William B. Carpenter, M.D., F.R.S. ; 
Sir John Lubbock, Bart., M.P., F.R.S.; William Kitchen 
Parker, F.R.S.; Francis H. Wenham, C.E. Treasurer— 
John Ware Stephenson, F.R.A.S.  Secretaries—Henry J. 
Slack, F.G.S.; Charles Stewart, F.L.S. Council—James Bell, 
F.C.S. ; John Berney; Robert Braithwaite, M.D., F.L.S. ; 
William J. Gray, M.D. ; Henry Lawson, M.D. ; Benjamin T. 
Lowne, F.L.S.; Samuel J. McIntire; John Millar, F.L.S. ; 
Henry Perigal, F.R.A.S.; Alfred Sanders; Charles Tyler, 
F.L.S.; Thomas C, White. Assistant Secretary—Walter W. 
Reeves, 
MANCHESTER 
Literary and Philosophical Society, Feb. 4.—Dr. J. P. 
Joule, F.R.S., &c., president, in the chair. E. W. Binney, 
F. R.S., paid a warm tribute to the memory of one of the most 
illustrious honorary members of the Society, the late Professor 
Sedgwick.—Prof. Williamson, F.R.S., stated that the second 
fossil plant described by Mr. Binney at the last meeting of the 
Society, Jan. 21, and of which a notice appeared in the Society’s 
Proceedings, does not belong to some new genus, as Mr. Binney 
supposed, but is one that he has already described on two or 
three occasions as being the stem or branch of the well-known 
genus Asterophyliites. The author said that he had obtained the 
plant in almost every stage of its growth, from the youngest twig 
to the more matured stem, and that the genus would be the sub- 
ject of his next, or fifth, of the series of memoirs now in course 
of publication by the Royal Society.—‘‘ On a large meteor seen 
on Feb, 3, 1873, at 10 F.M.,” by Prof. Osborne Reynolds,* 
On Feb. 3, at 1oh. 7m. (as afterwards appeared) by my watch 
(which was 7 minutes fast), I was walking from Manchester 
along the east side of the Oxford Road (which there runs 30° to 
the east of south), I had just reached the corner of Grafton-street, 
when I saw a most brilliant meteor. I first became aware of it 
from the brightness of the wall on my left, #2, on the north- 
east, which caused me to tum my head in that the wrong, 
direction ; the first effect was that of a flash of lightning, but it 
continued and increased until it was equal to daylight. On lift- 
ing my head I saw directly in front of me, what had previously 
been hidden by the brim of my hat, a bright object, apparently 
fixed in the sky, as though it were coming directly towards me; 
immediately afterwards it turned to the west, and passed just 
under the moon (which it completely outshone). I was very 
much startled when I first caught sight of it, owing doubt- 
less to the rapidity with which it was increasing in size, and 
the directness with which it seemed to be coming. The next 
instant I saw that it was only an extraordinary meteor. It 
passed the moon, falling at an angle of, I should say, 20°, and 
then ceased suddenly, having traversed a path of about go°, 
from the south to the east. The colour of the light was 
that of a blue light, or rather burning magnesium. The 
sky was cloudy, but there was no appearance of redness 
about either the head or the train. I endeavoured to fix its 
course by the stars, but it was too cloudy, although I could 
see here and there a star. The conclusions I came to, there 
and then, were that its course must have been nearly parallel 
with the road, which by the map runs, at that point, 30° to the 
west of north ; that when I first saw it it was about 40° above 
the horizon and due south ; and that it passed about 20° to the 
north of the moon. (This would make its line of approach from 
Pegasus.) While I was thinking of its course I heard a report, 
not very loud, but which I connected with it. I judged it was 
about 30° after the display. I then looked at may watch ; it 
was 10h. 7m. I then walked along, talking to a fellow-travel- 
ler who had not quite recovered his alarm. Presently we heard 
a loud report, like ashort peal of thunder or the firing of a large 
cannon ; I immediately looked at my watch, it was then 10h. fom., 
so that this second report was from three to four minutes after 
the display. I have no doubt that this was the report of the 
meteor, for compared with the other it was like the firing of a 
cannon to a musket. The time of the second report would 
make the distance 30 or 40 miles, so that it would have passed 
over Chester and burst over Liverpool. In this case it must 
have been a tremendous affair, for the sky was cloudy, and I do 
not think I exaggerate when I say that at one instant it was as 
light as day ; the train was very long, and the speed great. It 
ceased suddenly, as when a ball from a Roman candle falls into 
water ; there were no fi ents, as from an explosion.— 
*““Note on a Meta-Vanadic Acid,” by Dr. B. W. Gerland. 
—Dr. Roberts spoke on the subject of Biogenesis. (See 
his letter in this week’s NaTURE).—P.S. To Dr. Joule’s 
description of a Mercurial Air-Pump.—The exhauster described 
in the last number (p. 296) has been further improved by dis- 
pensing with the glass tube ¢, and its stop-cock f This is effected 
by attaching the base of the globe 4 to a strengthened india- 
rubber pipe, connected at the other end to a glass vessel of rather 
larger capacity than 6, This vessel has only to be successively 
raised and lowered in order to exhaust-the receiver. The mer- 
cury in the vessel may be either under atmospheric pressure or 
* See Natore, Feb. 6, p, 262, and Feb. 23, p. 200. 
