216 
NATURE 
[ Dec. 28, 1882 
Mr. Andrew Goldie.—Description of two fishes lately taken in 
or near Port Jackson, by William Macleay, F.L.S., &c.—On 
the physical structure and geology of Australia, by the Rev. J. E. 
Tenison-Woods, F.L.S., &c. This paper dealt at length with 
all the physical features of the Continent, viz. :—its mountain 
systems, its inland plains, and the portions intervening between 
the tableland and the sea, and its river-systems. Secondly the 
author enumerated the formations which had been recognised in 
Australia from the fundamental granite up to the recent alluvial. 
Showing that none of the large groups of rocks which are known 
in other parts of the world are absent from this continent. Re- 
ferences were made to the character of the fossils found, and the 
soils resulting from the rocks.—On a large cretaceous Mytilus, 
from the Barcoo, by the Rev. J. E. Tenison-Woods, F.G.S., 
&c. This paper was descriptive of a very large fossil Mytilus 
(JZ. ingens. sp. nov.), which was found in some mesozoic strata 
in Queensland, of probably Oolitic age. The paper also con- 
tained a brief reference to the collections of Mesozoic fossils 
made in Australia.—Notes on the inflorescence and habits of 
plants indigenous in the immediate neighbourhoo | of Sydney, by 
E. Haviland The author gives an account of his observations 
on the mode of fertilisation of two species of rutaceous plants 
common in the neighbourhood of Sydney—/PAilotheca australis 
and Boronia pinnata. In the former species the arrangement 
of the parts of the flower is such as apparently to specially 
favour self-fertilisation, but a closer observation shows that this 
is rendered physiologically impossible by the maturing and dis- 
charge of the pollen of each flower before the stigma comes to 
maturity. A similar phenomenon was observed in B. pznnaia, 
and the author suggests that the close opposition of the anthers 
to the stigma in these species until the pollen is almost ripe, may 
be designed in order to prevent, to some extent, the access of 
light and heat, and thus retard the maturing of the stigma until 
the pollen of its own flower has become discharged.—Note on 
some seaweeds from Port Jackson and adjacent coast, by E. P. 
Ramsay, F.L.S.—Mr. W. A. Haswell read a note on some 
points in the anatomy of the pigeons referred to by Dr. Hans 
Gadow ina recent paper on the anatomy of Pterocles.—Prof. 
Stephens exhibited a collection of rocks and fossils illustrating 
the structure of the Western coal-fields, as explained by Mr. 
Wilkinson in his map of Wallerawang (1877). 
BERLIN 
Physical Society, December 1.—Prof. Kirchhoff in the 
chair.—Dr. Hertz described and exhibited an apparatus he had 
constructed for demonstration of such weak electric currents as 
change their direction very often, several thousand times in a 
second. He called attention to the defects of the electro-dyna- 
mometers previously employed for the purpose, and showed that 
the electric heat-effect could most fitly be used in this case. The 
new dynamometer consists of an extremely thin horizontally 
stretched silver wire, the extension of which by heat, produced by 
the alternating currents, is observed. To this end the wire is, at 
its middle, wound round a vertical cylinder of steel capable of 
rotation about its axis, by turning of which the wire is stretched. 
Each extension of the wire through electric heating turns the cylin- 
der the opposite way to his torsion, and its rotation is observed 
by means of a mirror and telescope. This dynamometer, as 
Herr Hertz showed, is only applicable when the currents are 
weak, and the current reversals are very frequent ; that is, pre- 
cisely in cases where other measuring instruments fail.—Prof. 
Helmholtz then spoke on his thermodynamic investigations of 
chemical processes, and their relation to the electromotive force 
of galvanic batteries, and fully explained his views both on the 
reversibility of chemical processes and the electromotive forces 
in batteries ; also the experimental verification of these views in 
a ‘Calomel battery” comp-sed of zinc, chloride of zinc solu- 
tion, mercurous chloride, and mercury. The results hitherto 
obtained in these experiments and considerations, were brought 
by the author before the Berlin Academy of Sciences in July, 
and he is at present still engaged with the inquiry. 
Physiological Society, December 8.—Prof. du Bois Rey- 
mond in the chair.—Prof. Munk read a paper upon two investi- 
gations which had been carried out in his laboratory. The first 
of these was by Mr. M. Preusse, on the Tapetum in the retina 
of some mammals. It appeared from this chiefly anatomical 
investigation that a tapetum is always present in the eyes of dogs, 
horses, and cats ; and further that this tapetum is of an irregu- 
arly triangular shape and that the greater part of it is situated in 
the outer and upper quadrant of the retinal surface ; so that it 
is specially impinged upon by the rays that enter the eye from 
beneath ; over the median line and the equator of the 
retina the tapetum extends only a little, and this inwards 
and under. The point of entrance of the optic nerve always 
lies to the inside of the tapetum, which attains its greatest height 
above the nerve-papilla. In the case of all the animals that 
were examined, the situation of the tapetum corresponds with 
the region of most distinct vision. Hence is seen the correctness 
of Mr. Briicke’s view that the tapetum acts 2s a mirror at a 
plane behind the cones and rods that are sensitive to light, which 
sends back a second time through the axes of these cones and 
rods the rays of light that have already passed through them. 
This arrangement is of particular service to animals when the 
illumination is feeble, and it explains how the above-mentioned 
animals can distinctly see objects lying on the ground even when 
slightly illuminated, and consequently also at night-time, The 
second investigation on which Prof. Munk reported was that 
made by Dr. Karlin on the vaso-motor nerves. It is well known 
that Prof. Goltz has, from experimental evidence, laid down the 
doctrine that the blood-vessels have ganglion-cells on or in their 
walls, which cause the blood-vessels to contract, and which are 
connected with the central organs by means of vaso-motor 
nerves which generally dilate but also occasionally contract 
the blood-vessels. The well-established fact that a section 
of a nerve, ¢.g. of the sciatic nerve, is followed by an expan- 
sion of the vessels in its tract was regarded by Prof. Goltz as 
the result of the action of the vaso-dilator nerves stimulated by 
the section, and the after occurring contraction of the vessels as 
the result of the action of the peripheral vaso-motor centres which 
in course of time attain the preponderance. This doctrine had 
received support from Prof. Bernstein’s experiments, in whicha 
great dilatation of the vessels was observed to occur, on stimula- 
tion of the divided sciatic nerve, in extremities in which contrac- 
tion of the vessels had been induced by a great lowering of the 
temperature, and consequently a strong dilatation of the vessels 
was caused by direct electrical stimulation of the nerve. Dr. 
Karlin repeated the above experiment, and found its results con- 
firmed only when very strong currents were employed ; when, 
however, weak or moderate stimulation was applied, a contrac- 
tion instead of a dilatation of the vessels took place. Accordingly 
the dilatation of the vessels on powerful stimulation is to be 
regarded as due to a paralysis, and the experimental evidence for 
the existence of vaso-dilator nerves as inconclusive. 
CONTENTS Pass 
MatTHemartics In America. By J. W. L. GratsHer, F.R.'S. . . . 193 
Quain’s *“VANATOMY (U5 20 2 6 eb oe Met et oa ie canon CEE 
LxTTERS TO THE EDITOR :— 
Transit of Venus, December 6.—C. J. B. Witttams, F.R.S.  . - 297 
The Comet during the Last Month.—C. J. B. Witttams, F.RS . 198 
The Heights of Auroras.—T. W. Backhouse . . . . - ~~. ~ 198 
The Aurora and its Spectrum.—J. Rawp CapRON . . . . 198 
The Weather.—J. Ranp CAPRON. . «+ + - - © - + + «= 198 
A Common Defect of Lenses.—R. T. GLAZEBROOK . .« « » 198 
New Deep-Sea Fish from the Mediterranean.—Dr. Hexry 
HItyer GIGLIOLI 5 6 %: Key io in a). fet Uke, ole ke anSAES 
Electrieal Phenomenon.—A. J. K. oe DOP OrS Geno 
PHOTOGRAPHING THE Corona. By WiitiAmM Huacerns, D.C.L., 
LL.Dsjf RR Si wis fe wel natetatole eis) fel 6 oka f=) xo) dele PICO 
A WEDGE AND DIAPHRAGM PHOTOMETER (With Illustration). . . 201 
On THE OccURRENCE OF GREAT TIDES SINCE THE COMMENCEMENT 
or THE GEoLoGICAt Erocu. By Prof. Ropert S. Batt, LL.D., 
jah not aii OrmtOnd SDs Oooo 5G Oot See 
By Rev. T. W. WEBB (With Illustration). . » - 
Mars. ©), (a fey 
Destruction oF Lire 1N INDIA BY Potsonous SNAKES. By Sir 
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