DECEMBER 20, 1906 | 
NATURE 
189 
a linear differential equation which is a generalised form 
of that satisfied by the ordinary hypergeometric series, and 
the asymptotic expansions are related to the form of the 
differential equation. In the most important cases the 
asymptotic expansions become exponentially infinite at 
infinite distances.—The potential equation and others with 
function given on the boundary: L. F. Richardson. The 
paper suggests a tentative method for arriving at an 
approximate solution of the problem of steady flow of heat 
in a homogeneous solid with given surface temperature by 
beginning with the problem of variable flow in a solid of 
variable diffusivity which tends to zero on the boundary.— 
The limits of real variants: J. Mercer. The paper is 
occupied with generalisations of Cauchy’s theorem which 
is expressed by the formula 
limn=— (Xing — Xn) =limy—,, (277 Xn)- 
Royal Astronomical Society, December 14.—Mr. W. H. 
Maw, president, in the chair.—Solar parallax papers, 
No. 5: examination of the photographic places of stars 
published in the Paris Eros Circular: A. R. Hinks. Com- 
parisons had been made of the photographic places of stars 
obtained at Paris, Bordeaux, Catania, San Fernando, 
Toulouse, and Algiers, showing many discordances, some 
of considerable amount. The Algiers places were specially 
affected by ‘‘ magnitude equation,’’ the cause of which was 
very obscure. It appeared that many of the star places 
are affected by errors much larger than those considered 
permissible in the Astrographic Catalogue.—Account of the 
Oxford Astrographic Catalogue, vol. i.: H. H. Turner. 
The volume in question, which has just been published, 
contains measures of rectangular coordinates and diameters 
of star images on plates with centres in dec. +31°. The 
complete catalogue will consist of eight volumes, one of 
which will be devoted to discussions.—Notes on some 
spectroscopic observations of the sun: H. F. Newall. The 
observations were first made with the 25-inch equatorial 
at Cambridge (the Newall telescope), and later with a fixed 
horizontal telescope, a ccelostat, and auxiliary mirror; the 
latter equipment appeared to possess considerable advant- 
ages. An account was given of the preliminary experi- 
ments; the instrumental arrangements were described, and 
some results were given of the photographic study of the 
bands and flutings in the spectra of sun-spots.—Note on 
the approaching return of Halley’s comet: A. C. D. 
Crommelin. _The author directed attention to a paper 
by Dr. A. J. Angstrém published in 1862, in which a mean 
period for the comet of 76-93 years was deduced, with 
inequalities due to the action of Jupiter and Saturn. Dr. 
Angstrém’s results give 1913-08 for the time of the next 
perihelion passage, while that given by the Count de Ponté- 
coulant is 1910-37. In view of this large discrepancy of 
2-7 years, it is most desirable that the perturbations should 
be independently computed. Before the last return, in 
1835, there were at least five independent determinations 
of the orbit, and it would be a great misfortune if there 
is a serious error in the prediction of this return after the 
great success achieved in 1759 and 1835.—Photographs of 
Mira Ceti in 1897 and 1906, by Father Sidgreaves, were 
shown. There were marked differences in the relative 
intensities of the hydrogen lines.—Dr. Lockyer also 
showed photographs of the star taken at its present 
maximum. 
MANCHESTER. 
Literary and Philosophical Society, November 13.— 
Mr. C. Bailey in the chair—Luminosity produced by the 
rubbing or knocking together of various forms of silica: 
R. L. Taylor. The luminosity is connected in some way 
with the breaking away of small particles, mostly in the 
form of dust. Mr. Joseph Burton finds that whereas 
ordinary felspar only shows this property in a very small 
degree, the same substance previously heated almost to 
fusion shows it nearly as well as quartz. Common glass 
does not show it, but a specimen of glass “‘ frit,”? rich in 
lead and very hard, does to a slight extent. The luminosity 
may be partly due to the hardness of the material, but 
that it is not entirely so is shown by the fact that whereas 
a slight luminosity is shown when a piece of corundum or 
a piece of native emery is rubbed against a picce of silica, 
there is none whatever when two pieces of corundum or 
NO. 1938, VOL. 75| 
two pieces of native emery are knocked together. There 
is a curious odour produced by the impact of any of these 
bodies which become luminous, an odour which has been 
compared to that of ozone, but Mr. Taylor has not been 
able to verify that observation. Mr. F. Jones and Mr. 
Burton also made careful tests for ozone, and both failed 
to obtain any evidence of its presence.—The proembryo 
and bulbils of Lamprothamnus alopecuroides (Braun) : 
Miss M. MeNicol. This plant, which occurs in various 
countries of Europe and also in Africa, is characterised 
by the possession of unicellular bulbils or tubercles, formed 
by the transformation of rhizoids. 
CAMBRIDGE. 
Philosophical Society, November 12.—Dr. Hobson, presi- 
dent, in the chair.—(1) Electrification produced by heating 
salts; (2) secondary Réntgen rays: Prof. Thomson.— 
The specific heat of gases at constant volume and high 
pressure: W. A. D. Rudge. The author has determined 
the specific heat of carbonic acid by heating the gas in 
small steel bulbs immersed in a calorimeter containing 
paraffin. The value obtained was about o-45 tor a 
temperature range of from 36° to 60°, when the gas was 
under a pressure of about 480 atmospheres.—The radio- 
activity of the alkali metals: N. R. Campbell and A. 
Wood. It is found that potassium salts show a greater 
radio-activity than any substance examined which does 
not contain a ‘“‘ radio-active element.’’ The activity is an 
atomic property, and is not due to any impurity. The rays 
from potassium vary in penetrating power; the most 
penetrating rays are similar to the 8 rays from uranium. 
An activity of the same nature is observed in rubidium, 
but could not be detected in cwsium, sodium, or lithium. 
The rays from rubidium are far less penetrating than those 
from potassium. The ionisation caused by the rays from 
potassium is about 1/1000 of that caused by the B rays 
from a similar quantity of uranium. An apparently 
successful attempt has been made to obtain a photographic 
impression caused by the rays from potassium.—A relation 
between the ionic velocity and the volume of organic ions 
in aqueous solutions: G. A. Carse and ieee cabys 
This is a continuation of a previous paper (Proc. Camb. 
Phil. Soc., xiii., p. 287, 1906). It is found that the product 
ionic velocity x linear dimension of the ion, or va, is 
sensibly constant for the ions of twenty-two amines, the 
mean value being 20-2, for seven homologues of aniline 
18-8, for thirteen pyridines and quinolines 20-3, for five 
phosphines 17-6, &c. The linear dimension of an ion is 
taken as proportional to the cube root of the ionic volume, 
which is deduced from molecular and atomic volumes. It 
is shown from hydrodynamical considerations that yva= 
const. x (term depending on ionic shape). 
November 26.—Dr. Fenton, 
chair.—A _ delicate reaction 
Fenton. When bromo- or 
with sodio-malonic ester in 
duct is obtained solutions of 
blue fluorescence. The reaction is extremely delicate, 
and serves to detect the most minute trace of the 
above-named derivatives of methylfurfural. It is further 
shown that all hexoses and polysaccharides, glucosides, &c., 
which contain a hexose residue yield bromo-methylfurfural 
when acted upon by hydrogen bromide under appropriate 
conditions, and they may therefore be readily identified by 
the formation of this fluorescent product.—Xanthoxalanil 
and its analogues: S. Ruhemann. The author has studied 
the action of ethyl oxalate on acetanilide in the presence 
of sodium ethoxide, and has found that the compound 
thus formed, which is called xanthoxalanil, has the formula 
C,,H,,O,N,.—The influence of a strong magnetic field on 
the spark spectra of titanium, chromium, and manganese : 
J. E. Purvis. The strength of the field was 40,000 units, 
and Prof. Liveing’s 21-feet concave grating spectroscope 
was used. The general results showed that most of the 
lines were divided into triplets of which the middle con- 
stituent was at least twice as strong as the two outside 
ones, although the three constituents of several lines 
appeared to be more nearly equal. A number of lines 
were divided into four, and the two outside constituents of 
some were weaker and more diffuse than the two middle 
ones, whilst in several they appeared to be equally strong. 
vice-president, in the 
for carbohydrates: Dr. 
chloro-methylfurfural reacts 
alcoholic solution, a_ pro- 
which exhibit an intense 
