March 16, 1871| 

Gras communicates a paper on some botanical synonyms. The 
plants referred to in the last-mentioned paper are Lindernia 
palustris Crantz, anterior to Z. pyxidaria Linn., and identical 
with Anagalloides procumbens Krock. ; Scirpus quinqueflorus 
Crantz; Stelaria graminea Linn. ; Galeopsis segetum Neck. ; 
Euphorbia sequieriana Neck. ; and Statice cordata Linn., said to 
be distinct from the species so named by Gusson, which is here 
noticed as Statice Gussonit. 
THE Proceedings of the Bohemian Society of Sciences contain 
several papers by M. Emil Weyr on subjects belonging to the 
higher mathematics, the titles of which it would be useless to 
give here. One of his papers, however, is on the curves of maxi- 
mum and minimum electro-magnetic action.—Dr, A. Griinwald 
also communicates a paper on some differential equations with 
variable coefficients, and Prof. Blagek a short notice on the tri- 
axial ellipsoid. The titles of several natural history papers are 
given ; one by Dr. Schobl on the termination of the sensitive 
nerves in newly-discovered terminal corpuscles in the wing mem- 
brane of the chiroptera, and on the minute structure of the mem- 
brane is printed in full. This paper has appeared with illustra- 
tions in Siebold and Kolliker’s ‘* Zeitschrift fiir wissenschaftiche 
Zoologie.”—A short notice is g iven of a lecture by M. Wocel on 
the significance of stone and bronze antiquities in the primitive 
history of the Sclavonic tribes, founded on the study of a large 
collection of casts of such objects from the Ural, Altai, Caucasus, 
&e. 
THE Verein fiir Evdkunde in Dresden published last year its 
sixth and seventh annual reports, including its proceedings for 
the sessions 1868-69, and 1869-70. The abstracts of proceed- 
ings contain a multitude of short notes upon the results of travels 
made by members of the Society, and a report upon the doings 
of the sections of the Society in furtherance of its objects. Be- 
sides these, we have in an appendix three memoirs of some im- 
portance, namely, contributions to the knowledge of the Hotten- 
tots, by M. T. Hahn, relating especially to the language of the 
‘Nama ” tribes, but containing besides much interesting matter ; 
a geographical sketch of the Murray and Darling district in Aus- 
tralia, by Dr. H. Beckler; and a curious contribution to the 
history of geography during the latter half of the Middle Ages, 
giving an account of the maps and charts of the seafaring peoples 
of Southern Europe up to the first printing of Ptolemy’s 
Geography, by M. Heinrich Wuttke. 


SOCIETIES AND ACADEMIES 
Royal Society, March 9.—‘‘Results of Seven Years’ 
Observations of the Dip and Horizontal Force at Stonyhurst 
College Observatory, from 1863 to March 1870.” By the Rev. 
S. J. Perry. 
The object of the present paper is to bring further evidence to 
bear upon an important question of terrestrial magnetism. 
The existence of a sensible semi-annual inequality in the 
earth’s magnetic elements, dependent on the position of the sun 
in the ecliptic, was deduced by General Sir Edward Sabine from 
a discussion in 1863 of a continuous series of the monthly mag- 
netic observations taken at Kew. A previous reduction of ob- 
servations made at Hobarton and at Toronto had first suggested 
the idea, and a new confirmation of the results has lately been 
obtained by Dr. Balfour Stewart from subjecting a second series 
of Kew observations to the same tests as before. The observa- 
tions, which form the basis of the present discussion, extend over 
the period from March 1863 to February 1870, during which 
time the same instruments have been in constant use. These are 
a Jones unifilar and a dip-circle by Barrow, both tested at Kew, 
and a Frodsham chronometer. Sir Edward Sabine, who made 
the Stonyhurst Observatory one of his magnetic stations in the 
English survey in 1858, greatly encouraged the undertaking of 
monthly magnetic observations, and the Rey. A. Weld procured 
in consequence the instruments still in use. Only occasional 
observations were made with these instruments for some years, 
and it was only in 1863 that a continuous series of monthly deter- 
minations of the magnetic elements was started by the Rev. W. 
Sidgreaves. He observed regularly until September 1868, when 
I returned to my former post at the Observatory, and have con- 
tinued the same work ever since. 
A stone pillar was at first erected for the magnetic instruments 
in the open garden, and this remained in use from 1858 until the 
beginning of 1868, when a most convenient hut of glass and 
wood was built for the instruments in a retired corner of the 
NATURE 

397 

College garden. ‘This alteration was rendered necessary from 
the placing of iron rails in the vicinity of the old pillar ; and 
although it introduces into the results a correction for change of 
Station, it has the great advantage of securing immunity from 
disturbance for the future. 
Considering the object in view in drawing up this reduced form 
of the dip and horizontal-force observations, I have judged it 
advisable to adhere strictly to the tabular forms in which the 
matter has been presented in previous discussions of a similar 
nature. Each element is the subject matter of these tables. In 
the first are the monthly values of the element, the deduced 
me«n value, and its secular variation, Next in order comes the 
calculation of the semi-annual inequality. The residual errors, 
and consequent probable weights of the observations and results, 
compose the third and last table. 
The yearly mean values of the horizontal force are found to 
vary progressively from 3°5926 to 3°6178 in British units, the 
mean for Oct. Ist, 1866, being 3 6034, with a secular accelera- 
tion of 00042. Calculating from the monthly tables the mean 
value of the horizontal force for the six months from April to 
September, and for the semi-annual period from October toMarch, 
we find the former to be 0°0005 in excess over the latter, showing 
that this component of the intensity is greater during the summer 
than during the winter months. ‘lreating the dip observations 
in a precisely similar way, we obtain 69° 45’ 21” as the mean 
value of this element for October Ist, 1866, subject to a secular 
diminution of 1’ 49"'2; the extreme yearly means being 
69° 48' 47" and 69° 37’ 52". The resulting excess of 10" for the 
winter months in the computed semi-annual means is so small, 
that the observations tend mainly to show that the effect of the 
sun’s position is not clearly manifested by any decided variation 
in the dip. Deducing the intensity from the above elements, 
we obtain for the summer months the value 10°4136, whilst that 
for the winter months is 10°4128. The intensity of the earth’s 
magnetic force would thus appear to increase with the sun’s dis- 
tance, but the difference is not large enough to have more than a 
negative weight in the question under discussion. This weight, 
moreover, is lessened by the slight uncertainty arising from the 
probable disturbing causes at the first magnetic station. 
It is hoped that a second series of observations at the new 
station will throw greater light on the fact of the sun’s influence 
on terrestrial magnetism, by either confirming the results obtained 
above, or by adding fresh weight to the conclusions arrived at by 
the President of the Royal Society. 
“Preliminary Notice on the Production of the Olefines from 
Paraffin by, Distillation under Pressure.” By Dr. Thorpe and 
John Young, 
** Contributions to the History of the Opium Alkaloids, Part 
I.—On the Action of Hydrobromic Acid on Codeia.” By C. 
R. A. Wright, D.Sc. 
Mathematical Society, March 9.—Mr. W. Spottiswoode, 
F.R.S., president, in the chair. Mr. C. R. Hodgson, B.A. 
Lond., was elected a member : and the following gentlemen were 
proposed for election :—The Hon. J. W. Strutt, Major F. Close, 
R.A., and Mr. James Stuart, Fellow and Assistant-Tutor of 
Trinity College, Cambridge. Two models of surfaces were 
exhibited by Prof. Henrici, which had been exhibited and 
described at previous meetings of the society. Prof. H. J. S. 
Smith, F.R.S., read a paper on ‘‘ Skew cubics.” The secre- 
tary (Mr. Tucker) then read a communication from Prof. J. 
Clerk Maxwell, F.R.S., entitled ‘ Remarks on the Mathematical 
Classification of Physical Quantities.” The classification referred 
to was founded on the mathematical or formal analogy of the 
different quantities, and not on the matter to which they belong. 
Thus a finite straight line, or force, or velocity of rotation, &c., 
are quantities, differing in their physical nature, but agreeing in 
their mathematical form. The two methods of classification, the 
one just referred to and the obvious classification founded on 
that of the sciences in which the quantities occur, may be dis- 
tinguished by calling the first a mathematical and the second a 
physical classification of quantities. The secretary afterwards 
read a ‘‘ Note on the History of certain Formule in Spherical 
Trigonometry,” communicated by Mr. I. Todhunter, F.R.S., in 
which ti.> formulze usually known as Gauss’ Analogies were 
claimed for Delambre. Dr, Hirst presented ten ‘‘ Memoirs by 
M. Chasles” to the library of the society. 
Entomological Society, March 6.—Mr. A. R. Wallace, 
president, in the chair. Baron de Selys-Longchamps was 
elected an honorary member, the Rey. T, A. Preston an ordinary 
