Frsruaky 28, 1907 | 
NATURE 
431 
paper to record his own experimental results at nine, 
he should solve interesting problems using squared 
paper and logarithms and tables of sines and cosines 
at the age of ten and eleven, and he should get the 
notion of a rate long before he was twelve. He would 
have an elementary knowledge of the infinitesimal calculus 
before he was fourteen. He considered the elementary use 
of the calculus, and even the solution of easy differential 
equations, a school and not a university subject. Spherical 
harmonics and Bessel functions and their use in all sorts 
of physical problems with actual curve drawing, was an 
undergraduate study. Permutations and combinations and 
the theory of probability were post-graduate subjects, like 
the study of the fifth book of Euclid.—The magnetic field 
and inductance coefficients of circular, cylindrical, and 
helical currents: A. Russell. The author gives formule 
for the magnetic force near a circular current which can 
be readily evaluated. He then shows how the self- 
inductance of a ring of wire and the mutual inductance 
between two coaxial circular filaments can be found with- 
out using Neumann’s theorem. By Kelvin’s method, the 
results obtained can be applied at once to the correspond- 
ing problem of the simple vortex filament in hydro- 
dynamics. In this way expressions are found for the 
velocity of translation of a circular vortex filament—about 
which there appears to be uncertainty in hydrodynamical 
theory—and for the energy of the motion. The exact 
formula for the mutual inductance between a cylindrical 
current sheet and a coaxial helical filament of current is 
obtained. It is expressed both in terms of elliptic integrals 
and in the form of an algebraical series. 
MANCHESTER. 
Literary and Philosophical Society, December 11, 
1906.—Mr. Francis Nicholson in the chair.—The discovery 
by Biitschli of strontium sulphate as the basis of the 
skeleton in certain Radiolaria (Acantharia): Dr. F. W. 
Gambie. Working with material brought back by the 
German Antarctic Expedition, and also upon Mediterranean 
Acantharia, Biitschli has shown that strontium sulphate is 
the material of which the complex rods and spicules of 
these Radiolaria are composed. This is the first time that 
strontium has been described in animal tissues, and 
coincides with the recent discovery of barium sulphate in 
certain other deep-sea Protozoa (Xenyophophoridz).—The 
parichnos in the Lepidodendraceze: Prof. F. E. Weiss. 
This somewhat problematical organ appears as two small 
marks on the leaf scars of Lepidodendron and Sigillaria. 
It is found to consist of a thin-walled tissue communicating 
with the interior of the stem, and has been regarded by 
some as concerned in the transpiratory function of these 
extinct plants. Prof. Weiss brought forward arguments 
in favour of comparing them to the breathing pores of 
trees known as lenticils.—The structure of syringodendron, 
the bark of Sigillaria: Miss K. H. Coward. An account 
was given of a particular instance of the above-mentioned 
breathing pores in Sigillaria. 
January 15.—Sir W. H. Bailey, president, in the chair. 
—The positions of Mendeléeff’s groups of chemical 
elements: C. E. Stromeyer. With the help of an 
empirical formula, which, like Stoney’s logarithmic spiral 
of the cube roots of the atomic weights, gives average 
results, the author has calculated the mean positions of 
the various chemical groups, and finds that they are not 
equidistant, but are irregularly spaced like the musical 
notes of the major or minor scale. — Dividing the iron 
groups into three, viz. iron, nickel, and cobalt, the chief 
irregularities may be summarised as follows :—The man- 
ganese and the iron groups, as well as the nickel and 
cobalt groups, fall nearly together, viz. 6-64, 6-82, and 
7°59, 7-30, whereas the oxygen and fluorine groups, the 
cobalt and sodium groups, and the magnesium and 
aluminium groups are separated from each other by about 
one and a half average group intervals, viz. 5-27, 6-64, and 
7:80, 9-29 and 9-82, 11-37. By assigning their mean posi- 
tions to the groups, instead of the whole numbers (one to 
sixteen) as has been done previously, the author’s empirical 
formula expresses very accurately the atomic weights, the 
chief discrepancies being found amongst the recently dis- 
covered rare elements and amongst the sulphur group. 
NO. 1948, VOL. 75] 
The conclusion arrived at by the author is that the atomic 
weights cannot be expressed by a single continuous curve, 
even if irregular positions are assigned to the groups. 
January 29.—Mr. Francis Nicholson in the chair.—A 
confusion of two species of Lepidodendron (L. Harcourtii, 
Witham, and L. Hickit, sp.nov.) under L. Harcourtit, 
Witham, in Williamson’s nineteenth memoir, with a de- 
scription of L. Hickit, sp.noy.: D. M. S. Watson. In 
his nineteenth memoir, Williamson describes several stems 
as L. Harcourtti, Witham. Examination of these sections 
has shown that whilst one is probably L. Harcourtii, the 
majority belong to a type which differs from L. Harcourtii, 
Witham, in several particulars.—A collection of mammals 
made by Mr. S. A. Neave in Rhodesia, north of the 
Zambesi, with field notes by the collector: R. C. 
Wroughton. 
Paris. 
Academy of Sciences, February 18.—M_ Henri 
Becquerel in the chair.—The president announced the death 
of M. Marcel Bertrand, member of the section of miner- 
alogy.—Researches on the combinations between carbon 
and free nitrogen: M. Berthelot. When acetylene is de- 
composed by electric sparks, there is no trace of the reverse 
reaction, the formation of cyanogen from its elements. 
The author holds that there is no conclusive evidence that 
carbon and nitrogen combine directly at any temperature ; 
observations to the contrary are due to the impurities in 
the carbon or nitrogen.—Some catalytic reactions effected 
under the influence of wood charcoal: Georges Lemoine. 
At a temperature of 350° C. wood charcoal causes the 
decomposition of alcohol into hydrogen and aldehyde. 
Hydrogen peroxide is freely decomposed into oxygen and 
water at low temperatures, and the reaction between iodic 
acid and oxalic acid is also accelerated by charcoal.— 
Remarks on the spectroheliograph: G. Mitlochau. Com- 
menting on a recent paper by MM. Deslandres and 
Azambuja, the author directs attention to the spectro- 
heliograph described by him in conjunction with M. 
Stefanik two years ago, and gives fuller details of the 
arrangement.—The theory of gases and globular clusters : 
H. v. Zeipel. An application of the theory of gases to 
the study of the distribution of stars in globular clusters. 
—A simple apparatus reproducing all the peculiarities of 
Foucault’s experiment on the rotation of the earth: G. 
Blum.—OQuasi-integral and quasi-meromorphic functions : 
Edmond Maillet.—The growth of integrals of differential 
equations of the first order: Pierre Boutroux.—The con- 
struction of a radius of curvature of the curves enveloped 
in the most general movement of a solid body: G. 
Koenigs.—The variation of the vapour pressure as a 
function of the pressure and the determination of the 
ebullioscopic constants: Georges Baume and D. E. 
Teakalotos.—Some molecular combinations of metallic 
halides with organic compounds: V. Themas. The re- 
action between certain metals, such as zinc, aluminium, and 
magnesium, is accelerated by organic substances, such as 
ether or alcohol. The author has made a systematic study 
of the various classes of organic substances capable of in- 
ducing this reaction. Besides ether and alcohol, the fatty 
ketones, the diketones, and nitriles all induce the reaction. 
The aromatic Ketones, on the other hand, paraldehyde, and 
certain aromatic aldehydes, are without effect. These 
effects are traced to the formation of molecular compounds 
of the type CH,.CO.CH,.MgI,.—Note concerning the 
estimation of gold by the wet: method in auriferous sands : 
Albert Fournier. The presence of iron is the main 
difficulty in the estimation of gold in the wet way; the 
method described shows how this difficulty can be avoided. 
—The reducing and catalytic power of amorphous carbon 
towards alcohols: J. B. Senderens. Finely divided, care- 
fully purified animal charcoal was used in the experiments. 
At 400° C. ethyl alcohol gives ethylene and methane, with 
small quantities of hydrogen, carbon monoxide, and 
dioxide. With propyl alcohol, the gases contained pro- 
pylene (88 per cent.) ethane, with small quantities of 
hydrogen and carbon monoxide. Fine sand exerts a 
stronger catalytic action than charcoal, and may be used 
with advantage in the preparation of certain ethylenic 
hydrocarbons. Red phosphorus at 200° C. to 240° C. 
induces this catalysis even better than sand.—The migra- 
tion of the soluble principles in the plant: G. André.— 
