526 
4 per cent. of the mean value of the range during the period 
dealt with. On the whole, the agreement is distinctly less 
good in the case of vertical force than in the case of declin- 
ation, inclination or horizontal force. 
March 17.—‘ On the Construction of some Mercury 
Standards of Resistance, with a Determination of the 
Temperature Coefficient of Resistance of Mercury.’ By 
F. E. Smith, A.R.C.Sc., Assistant at the National Physical 
Lakoratory. Communicated by R. T. Glazebrook, M.A., 
F.R.S 
This paper contains an account of the construction and 
measurement of eleven mercury standards of resistance at | 
the National Physical Laboratory. 
A comparison between the international ohm as realised 
from these standards and the unit of resistance derived 
from the coils belonging to the British Association shows 
that 
Resistance of unit derived from 
Resistance of 1 int. ohm | _ g 
(as realised at the N.P.L.) i) | Daeiee eu as equal 
= 0.00008, ohm. 
A very concordant series of observations also indicates 
that 
Resistance of 1 int. ohm . 9 
(as realised at the Reichs- feat SE Enea Se 
anstalt) 
=0 00002, ohm. 
The methods adopted both for the construction and 
evaluation of the mercury standards are very different from 
those which have been previously employed, one of the 
methods of erection enabling the ‘* end effect ’’ of the tubes 
to be eliminated. Owing to the increasing accuracy of 
electrical measurements, it was thought desirable to realise 
the international ohm with a probable error not exceeding 
one part in one hundred thousand. The results obtained 
with the eleven mercury standards of resistance are in very 
close agreement, the calculated probable error of the deter- 
minations being +0-0008 per cent. only. 
The temperature coefficients of resistance of (1) mercury 
in Jena 16' glass, of (2) mercury in verre dur glass, and 
of (3) a constant volume of mercury, have also been deter- 
mined for a range of temperature 0° C. to 22° C. The 
results are as follows :— 
(1) Mercury in Jena 16'’’ glass, 
R,=R 
(2) Mercury in verre dur glass, 
R,=R,[1+0-00088036T + 0-00000103094T*]. 
(3) A constant volume of mercury, 
Deduced from (1) 
R,= R,[1+0-00088788T + 0-00000105641"]. 
Deduced from (2), 
R,=R, [1+ 0-00088776T + 0-0000010376T*]. 
T being the temperature on the hydrogen scale. 
o[1+0-00088018T + 0-00000105793 17]. 
the Relation of 
““The Specific Heats of Metals and 
lili; By Prof. 
Specific Heat to Atomic Weight. Part 
W. A. Tilden, F.R.S. 
The object of the experiments, of which an account is 
given in this paper, was to determine whether the atomic 
heats of the elements entering into combination are pre- 
served in the compound at all temperatures, previous results 
obtained by the author and others having shown that the 
specific heats of metals of small atomic weight, such as 
aluminium, increase very rapidly with rise of temperature. 
As it is not possible to determine the specific heat of 
sulphur throughout a long range of temperature, tellurium 
was chosen for experiment. Compounds of tin, silver and 
nickel with tellurium were prepared, and two alloys of 
silver and aluminium. ‘The average specific heats of all 
these elements, except tin, which melts at 232° C., were 
determined over various intervals from the boiling point of 
liquid oxygen to nearly 500° C. in the case of the less 
fusible elements, a range of about 680° C. From these 
mean specific heats the true specific heats at intervals of 
C. 
NO 
100° absolute temperature were 
. 1796, VOL. 69 | 
calculated, and from 
NATURE 
[MaARcH 31, 1904 
the specific heats the atomic heats were deduced. The mean 
specific heats of the compounds, formed by their union, were 
also determined, and from these data the molecular heats 
of the compounds calculated. On comparing the sum of 
the atomic heats of the elements present with the molecular 
heat of the compound at the successive temperatures, it was 
found that there is throughout a close concordance. The 
order of difference may be shown by one example :— 
Nickel Telluride, NiTe. 
Temperature, Sum of atomic heat Molecular heat of 
absolute of Niand Te NiTe 
100° 9-20 8.38 
200° 11-08 11-35 
300° . 42 22 12-41 
400° . 13-00 12:92 
500° . 13-49 13-15 
600° . 13 85 13:28 
700° 14-11 13°35 
The results of these experiments show that Neumann’s 
law is approximately true, not only at temperatures from 
o° to 100° C., but at all temperatures. They thus support the 
view that the specific heat of a solid is determined by the 
nature of the atoms composing the physical molecules, and 
is not a measure of the work done in thermal expansion. 
The paper concludes with a discussion of the relations of 
specific heat to atomic weight under different physical con- 
ditions, that is, in the solid, liquid and gaseous states. 
Entomological Society, March 2.—Frof. E. B. Poulton, 
F.R.S., president, in the chair—Commander J. J. Walker, 
R.N., exhibited (1) Hecatesia fenestrata, Bdy., an interest- 
ing Australian moth, the G possessed of a very marked 
power of stridulation (stridulating organ on longitudinal 
transparent bar on fore-wing), known in New South Wales 
as the ‘‘ whistling moth’’; (2) Dodonidia helmsi, Butler, 
a rare satyrid butterfly from New Zealand; and (3) a 
gigantic species of the Thysanurid genus Japyx, found at 
Picton, New Zealand.—Mr. C. O. Waterhouse exhibited 
and commented upon a diagram of the mouth of one of 
the Mallophaga (Laemobothrium  titan).—Mr. G. C. 
Champion exhibited specimens of the two species of 
Dorcadion found during his recent journey in Spain, 
D. almarzense, Esc.? from the summit of Montcayo, and 
D. neilense, Esc., from the Sierra de Logromo. He also 
exhibited numerous examples of Pyropsyche moncaunella, 
Chapm., found by Dr. Chapman and himself on Montcayo- 
—Mr. A. J. Chitty, Mr. Jennings and other fellows ex- 
hibited specimens of the genus Tropiphorous to determine 
if possible whether T. tomentosus and T. obtusus were in 
reality one and the same species. Various cases of coinci- 
dent localities for the species were quoted, and it was the 
general opinion that in the United Kingdom the two were 
but forms of one species.—Dr. F. A. Dixey read a note on 
the so-called ‘‘bugong’’ moth consumed by some 
Australian natives for food. He said it was not a Euploea 
at all, as supposed by Kirby in his ** Bridgwater Treatise,’’ 
but a Euxoa, and not a butterfly as also stated by West- 
wood.—The President exhibited a specimen of a beetle, 
Glenea pulchella (Thoms.), one of three individuals of the 
species taken in the Nilgiris by Mr. Leslie Andrewes, which 
clearly mimics a large ichneumon fly not yet identified. 
—Mr. L. B. Prout exhibited, on behalf of Mr. A. Bacot, 
long bred series of Triphaena comes, Hb., the result of 
breeding for two generations from a wild © of the curtisit 
form, taken near Forres. In the first generation, rather 
more than half the progeny followed, to a certain extent, the 
parent ©, though varying from rich deep red to almost 
black. Pairings of these dark specimens resulted in a brood 
in which the percentage of ab. curtisii was slightly in- 
creased, although the type forms were still well represented ; 
but it was noticeable that in every specimen the orbicular 
stigma was filled up with the darker or melanic colour.— 
Papers :—Notes on Australian and Tasmanian Crypto- 
cephalides, with descriptions of new species: A. M. Lea.— 
A revision of the subfamily Pelidnotinze of the coleopterous 
family Rutelida, with descriptions of new genera and 
species, by the late F. Bates. On some new species of 
eastern Australian and African moths in the British 
Museum: Colonel Charles Swinhoe.—An _ entomological 
excursion to Montcayo, Spain, with some remarks on the 
