| JUNE 26, 1902] 
NATURE 
215 
although the season on the coast would be over when that upon 
the high mountains commenced.—Mr, S. L. Hinde read a 
paper, illustrated by lantern slides, upon the protective re- 
semblance to flowers borne by an African Homopterous insect, 
Flata nigrocincta, Walker. He said that ‘‘the cluster of in- 
sects grouped to resemble a flower spike,’ which forms the 
frontispiece of Prof. J. W. Gregory’s ‘‘ Great Rift Valley,”’ 
had attracted some criticism, and that as he was familiar with 
the insect figured, and with its larva, in a wild state, it seemed 
desirable to publish the evidence. In the plate the insects are 
collected on the vertical stem, the green individuals uppermost 
considerably smaller than the red ones beneath, like thesunopened 
green buds towards the top of a flowering spike as compared 
with the expanded blossoms below. The separate representa- 
tions of the green and red forms, however, indicate no difference 
in size, and experience confirms this conclusion, so that the im- 
pression conveyed by the frontispiece plate is erroneous. 
further noting that the uniform deep pink colour of the exposed 
parts of the insects figured was also incorrect, Mr. Hinde re- 
marked that he had never seen the insects grouped according 
to their colours, but invariably mixed, that he had never found 
larvee and imagines on the same stem or even together on the 
same tree or bush, nor did the imagines affect vertical stems, 
but always those actually or approximately horizontal. Sir 
George Hampson said the insects figured were orange when 
brought home, and the pink-winged imago was an error of the 
colorist. 
Mineralogical Society, June 10.—Dr. Hugo Miller, 
president, in the chair.—Dr. A. Hutchinson gave an account of 
the experiments he had made in order to discover the cause 
of the discrepancy in the results obtained by Meigen and 
Panebianco in the application of Meigen’s method of discrimin- 
ating calcite and aragonite. He found that calcite, when treated 
with a boiling dilute solution of cobalt nitrate, only remains 
white or becomes yellow (as stated by Meigen) when the cobalt 
nitrate contains traces of iron, and that Panebianco’s lavender- 
blue colour is only obtained when the cobalt nitrate is free from 
iron.—Mr. G. F. Herbert Smith discussed some crystals of 
krennerite from Nagyag on which he found a large number of 
forms not previously recorded. He further exhibited the new 
three-circle goniometer recently constructed from his designs by 
Messrs. Troughton and Simms for the British Museum. He 
pointed out the advantages of the gnomonic projection in 
crystallography, and showed a table which he had prepared to 
facilitate the employment of this method of projection.—Mr. 
G. T. Prior exhibited specimens and described the mineral con- 
stituents of the volcanic dust which fell in Barbados on May 7 
and 8 after the eruption of the Soufritre of St. Vincent. 
The fact that the constituents are like those of a hypersthene- 
augite-andesite connects the eruptions with the Pacific rather 
than with the Atlantic volcanic chain.—Mr. L. J. Spencer 
pointed out reasons for the non-existence of “ kalgoorlite’”’ and 
“*coolgardite” as mineral species. _At Kalgoorlie, in Western 
Australia, with the tellurides of gold and silver,  syl- 
vanite ((Au,Ag)Te,), calaverite ((Au,Ag)Te,), and petzite 
( (Ag, Au),Te), is frequently associated the telluride of mercury, 
coloradoite. The iron-black petzite and coloradoite are iden- 
tical in external appearance, and sometimes occur intimately 
associated together. In such cases minute fragments detached 
from an apparently homogeneous mass are found on blow- 
pipe analysis to be sometimes coloradoite and sometimes petzite. 
Analysis of larger pieces would therefore show the presence of 
tellurium, gold, silver and mercury in variable proportions, 
as is actually the case in the analysis of ‘‘kalgoorlite” and 
“*coolgardite,” described as new mineral species by Pittman in 
1897 and by Carnotin 1901 respectively. Neither of these in- 
vestigators appears to have been aware of the occurrence of 
coloradoite at Kalgoorlie, and the materials they analysed were 
without doubt mechanical mixtures of coloradoite and the 
above-mentioned tellurides of gold and silver, especially petzite. 
—Mr. R. H. Solly described the crystallographic characters of 
liveingite, a new sulph-arsenite of lead (5PbS.4As,S.) from 
the Binnenthal, a preliminary account of which was given by 
him in the Proc. Cambridge Phil, Soc., 1901, xi. p. 239. 
Measurements of three good crystals more recently obtained, 
showed that the system was orthorhombic, and that 100, 110 = 
44° 49’; O10, O11 = 46° 48’; oor, tor = 43° 23’. In the prism 
zone the faces (210), (430), (540), and in the macrodome zone 
the faces (302), (504), (908), (101) are well developed, and (100) 
NO. 1704, VOL. 66] 
After | 
isa cleavage plane. A pyramid zone with numerous small 
faces is also present. The crystals often exhibit a polysyn- 
thetic growth parallel to (100). In appearance they resemble 
rathite. 
Mathematical Society, June 12.—Dr. E. W. Hobson, 
president, in the chair.—The president announced that the 
council had awarded the De Morgan medal, 1902, to Prof. A. G. 
Greenhill.—Prof. Love communicated a paper by Prof. Conway 
on Huygens’ principle in a uniaxial crystal. It is shown that, 
when electric waves are propagated ina crystalline medium 
with an axis of symmetry, the radiation is resolvable into con- 
stituents (1) with electric force at right angles to the axis, (2) 
with magnetic force at right angles to the axis, (3) with both 
forces at right angles to the axis. The types of radiation that are 
due to electric and magnetic doublets with their axes parallel 
and perpendicular to the axis of symmetry are determined, and 
it is shown that the radiation received at any point can be re- 
garded as made up of secondary waves due to such doublets 
distributed upon an arbitrary surface separating the point from 
the actual sources of the radiation. —Lieut.-Colonel Cunningham 
gave an account of some investigations on repetition of the sum- 
factor operation. The result of the repetition of the operation 
upon a_number is very frequently unity when the operation is 
repeated sufficiently often; in the case of one small class of 
numbers the result is a perfect number ; in another small class, 
a pair of amicable numbers; in a third small class, the result 
may increase beyond the power of practical calculation. —The 
following papers were communicated from the chair:—M. E. 
Picard, Sur un théoreme fondamental dans la théorie des 
équations différentielles. This note deals with the question of 
the possibility of the existence of a non-holomorphic integral, 
which, besides satisfying a given ordinary differential equation, 
also satisfies a special condition at a certain point.—Mr. G. H. 
Hardy, some arithmetical theorems. Cauchy’s theory of resi- 
dues is used to obtain various relations between sums of terms 
b 7 ; , 
of the form ((2)) in which @ and @ are fixed integers, and 
c is an integer which ranges over a certain set of values, the sum- 
mation is taken with respect to o, and ((x)) denotes the algebraic 
difference between « and the absolutely nearest integer. —Prof. 
M. J. M. Hill, on a geometrical proposition connected with the 
continuation of power series. A power series with a circle of 
convergence C, having been derived from a given power series 
with a circle of convergence Cy, it is possible to choose succes- 
sive positions of a point ., so that every point of the region that 
is common to Cy and C, shall be within one at least of the 
circles described with x as centre to touch C, and C, internally. 
—Mr. J. H. Grace, on types of perpetuants. The numbers of 
perpetuants of one or more forms have been determined by 
Stroh and MacMahon, and the latter has accounted for each 
perpetuant by a corresponding umbral form. In the present 
paper the perpetuants of any number of forms are found by the 
direct reduction of Aronhold’s symbolical forms. 
Royal Meteorological Society, June 18.—Mr. R. 
Inwards, vice-president, in the chair.—Mr. F. C. Bayard read 
a paper on English climatology, 1891-1900, which is a dis- 
cussion of the climatological data printed in the ‘‘ Meteorological 
Record.” In 1874, the Royal Meteorological Society com- 
menced the organisation of a series of stations at which the 
observations are made twice a day on a uniform plan, so that 
the results may be strictly comparable with each other. In 
addition to these the Society in 1880 organised another class of 
stations, termed ‘‘ climatological,” at which the observations 
are made once a day, viz. at 9a.m. Mr. Bayard on a former 
occasion worked up the results from these climatological stations 
for the ten years 1881-90, and in the present paper he gives the 
averages from sixty-nine stations for the ten years 1891-1900. 
The elements dealt with are temperature, relative humidity, 
amount of cloud, rainfall and rainy days, and the results are a 
valuable contribution to the climatology of the British Isles. — 
A paper by. Mr. W. L. Dallas on earth temperature observa- 
tions recorded in Upper India was also read, in which the 
author discussed the observations made on the temperature of 
the soil at three stations, viz. Lahore, the capital of the Punjab; 
Dehra Dun, in the north-west of the North-Western Provinces ; 
and Jaipur, the capital of the native State of that name. The 
observations, which were made at depths varying from 4 inches 
to 454 feet below the surface, extended from 1884 to 1899. 
