the melting-point of the mercuric chloride, though still sur- 
rounded by the solid salt, When the salt is in the form of a 
soliditied cylinder, the temperature rises 15° above the melting- 
point. When aturpentine calorimeter is used, the temperature 
‘of the mercuric chloride came out 100° above the ordinary 
melting-point ; but with petroleum or benzine, temperatures 
above the ordinary melting-point could not be obtained. The 
author therefore withdiaws his previous statement, and concludes 
that although mercuric chloride does not fuse when heated under 
diminished pres-ure, yet its temperature never rises appreciably 
above its ordinary melling-point. The high temperatures indi- 
cated by the thermometer being due to the diffusion of the super- 
heated vapours of the mercuric chloride through the pores of the 
solid salt. The author also concludes that turpentine cannot be 
used in a calorimeter for the determination of the specific heat 
of bodies soluble in water, since some substances such as mer- 
curic chloride, zinc chloride, &c., when heated, cause an evolu- 
tion of heat, due probably to the polymerisation of the turpentine. 
Hence many of Kegnault’s specific heat determinations, in 
which turpentine was employed, are probably too high; they are, 
it may be remarked, in almost all cases higher than Kopp’s 
numbers, that observer having used coal-tar naphtha. ‘The 
specific heat of mercuric chloride is 0'06425, and of zinc chloride 
0714301, neither value being altered by a rise of temperature.— 
‘Coutnbutions to the history ef cerium compounds, including the 
analysis of Rbabdojhane, a new British mineral containing 
Cerium, Lanthanum, l/idymium, Yttrium, by W. N, Hartley.— 
On the reaction of chromic anhydride with sulphuric acid, by 
C. F. Cross and A. Higgin.—On dibenzoybanilin and its 
isomerides, by A. Higgin. 
Entomological Society, January 18.—Annual Meeting.— 
An address was delivered by the president, H. T. Stainton, 
F.R.S., and the following gentlemen were elected to serve on 
the Council for 1882 :—President, H, T. Stainton, F.R.S. 
Treasurer, E. Saunders, F.L.S. Librarian, F. Grut, F.L.S. 
Secretaries: E. A. Fitch, F.L.S., and W. F. Kirby. Other 
Members of Council: W. Cole, F. Du Cane Godman, F.L.S., 
F. P. Pascoe, F.L.S., O. Salvin, F.R.S., W. A. Forbes, B.A., 
F.L.S., F.G.S., Rev. H..S. Gorham, Lord Walsingham, M.A., 
F.Z.S., and C, O, Waterhouse. 
PARIS 
Academy of Sciences, January 23.—M. Jamin in the chair. 
—he f.llowing papers were read :—On the explosive wave, by 
M. kerthelot. It is not a sound-wave trayellmg with a velocity 
depending on the physical constitution of the medium, but a 
change of chemical constitution propagated. M. Berthelot re- 
capitulates its properties. As to dependence of the velocity on 
the diameter, this becomes less and less as the increase of the 
diameter allows more freedom of motion to the molecules and 
diwini-hes friction. The total energy of the gas, at the moment 
of explo-ion, depends on its initial temperature and the heat 
liberated during combination, These two data determine the 
absolute temperature of the system, which, moreover, is propor- 
tional to the kinetic energy (4/zv*) of translation of the molecules. 
It follows that the velocity of translation is proportional to the 
square root of the ratio between the absolute temperature and 
the den ity of the gas referred to air, The result of experiments 
agrees clo-ely with this.--Réswmé of meteorological observations 
made du ing 1881 at four points of Haut-Rhin and the Vosges, 
by M. Hirn. The stations are—Thann (alt. 350 m.), Munster 
(alt. 388 m.), Col de la Schlucht (alt. 1154 m.), and Colmar (alt. 
195 m.). /ver alia, the maximum difference between a black- 
bulb thermometer and an ordinary one at the same height in 
shade at Colmar was 27°6 (in January). The most violent winds 
at Col var never exceeded 18 to 20 metres per second. The 
rainfall at Schlucht was 1310°8 mm., at Munster 664 mm., 
at Colmar 521 mm,—Spectroscopic observations with mono- 
chrmatic hght, by M. Zenger. Seeking combinations which 
should give stro g dispersion with perfect transparency and 
total reflection «f red or violet, he finds that benzine and 
benzylene, combined with quartz, eliminate the extreme red of 
an angle of about 75°, while pure anethol, at the same angle, 
eliminates the extreme violet. A parallelepiped thus formed 
is the best means of observing the solar protuberances or spots, 
or the rever-ed colours of the chromosphere. He commends it 
to the Trausit of Venus Commisston. Irradiation is abolished 
or greatly reduced. Larger magnifying power may be used, 
The c nfusion arising from interference-bands at the edge of 
Venus’ disc is obviated. And better photographs may be had. 
NATURE 
Ba = ih i 
[Zed. 2, 1882 
SE ee 
—Remarks on a note of MM. Mignon and Rouart, on processes 
of coppering, by M. Weil. He denies that he uses organic acid 
merely as an accessory.—On the spherical representation of 
surfaces, hy M. Darboux.—On some transcendent equations, by 
M laguerre.—On Fuchsian functions, by M. Poincaré. —On a 
means of extending the theory of imagmaries, without making 
use of imaginaries, by M. Saltel.—New manner of employing 
the principle of least action, in questions of dynamics, by M. 
Brassinne.—Determination, by means of the microphone, of the 
nodes and ventral segments in vibrating columns of air, by M. 
Serro-Carpi. A small graphite microphone is applied to an 
elastic membrane on a ring, and this is brought into the sound- 
ing-pipe. The presence of a node is indicated by a roll (vox/le- 
ment) in the telephone, like that which the instrument gives 
with induced currents. In the ventral segments the sounds are 
more apart and rare. One does not hear the musical sound of 
the pipe.—On spermatogenesis in Annelids and Vertebrates, by 
M. Sabatier, In Annelids he has observed two generations of sper- 
ma'ol)lasts formed onthe inner surface of the spermatic pouches. 
The second, springing from the first, are transformed into sper- 
matozoids (the nuclei forming the heads), M. Sabatier considers 
that spermatogenesis in Vertebrates may be similarly explained. 
—On the 7é/e of the amnios in the production of anomalies, by 
M. Daresti. In an anomalous fcetus of sheep he finds confirma- 
tion of his view that deviations, and especially congenital club- 
foot in man, are the consequence of compression of the body of 
the embryo by the amnios arrested in its development.—On the 
vegetation of aquatic plants in air, by M. Mer. He concludes, 
that if certain aquatic plants cannot form branches in free air, it 
is simply because their tissues are unable to resist active transpi- 
ration, and not, as in the ease of aerial plants immersed, because 
they are incapable of development and nutrition in air. They 
can live in air, provided this is moist, and can produce starch in 
it sometimes more easily than in water. But there are very few 
in which the same leaf will act in both media.—On the con- 
centric bands of felspars, by M. Lévy.—On the barometric 
height of January 17, 1882, by M. Renou. This on the pare de 
Saint Maur (alt. 49°30 m.) at 10 a.m. was 78213 mm. ; reduced 
to sea-level, 786°92 mm. During nearly a century, there has 
only been one height slightly exceeding this, at Paris Observa- 
tory. On February 6, 1821, at 9 a.m., the height was 780°90 
mm., at sea-level, 787°52mm. It would appear that at Paris 
during two centuries, with exception of the figures in 1821 and 
1882, the barometer has never exceeded 778°5 mm. M. Renan 
gave an explanation of the recent high pressure. M. Faye attri- 
buted to the pressure a remarkable depression of the sea-level 
observed at Antibes (in the south of France), about which M. 
Naudin had written him, It lasted a fortnight. 
CONTENTS 
Scigntiric Worruims, XIX.—ADoLF Ertk NorpenskJitp (With 
Steel Plate Engraving)... + +. +. a’ War tage ane 
Tue Possipitiry oF FINDING WorKABLE CoAL-SEAMS UNDER THE 
Lonpon Arka. By Prof.Joun W. Jupp, F.R.S.. . . « - « . 3m 
Tue Encyctopapia BRITANNICA » « « s © « oo, eat a ee 
PAGE 
Our Book SHELF :— 
“The Year Book of Pharmacy”” . . - + » « © + = © » ~ 385 
Hatton’s “New Ceylon” . 2 « © = = shes =e «) ey 
Lerrers To THE EpiToR :— 
Earth-Currents.—WILtt1amM Exuis; Rev. S. J. Perry, F.R.S. ; 
G. M. Wurepig; J. PARNELL . «© - + + + « © © 2 + = 335 
Variations in the Sun’s Heat —E. DouGcas ARCHIBALD. . . ~ 316 
Solar Observations.—Sir W1Lt1am Tuomson, F.R.S.. 0. . + = 316 
On the Climate of North Northumberland as regards its Fitness 
for Astronomical Observations.—Rev. Javon J. Muschamp 
PERRYS. 02 ie de ee ya Nese Boos ee), Se 
Primitive Traditions as to the Pleiades.—R. G. HALiBuRTON . . 317 
ON THE VRGETABLE Foop OR THE New ZEALANDERS IN Pre- 
HISTORIC TIMES. ah adel cnine: 6) ete): woe Ue ee Oe ere 
Samuet SHarr. . . « Sn Saw nek & ene ees e «319 
Tue Aurora, I. (With Illustrations)... « . + 6). 6 + 2 + 399 
TuHEopoR ScHWANN. By Prof. E. Ray Lankester, F.R.S. . - ~ 32% 
Woorara (With Illustration) . 2 6 6 6 ee ee * 323 
NOTES.fia" 0 2s) ap erence” fae (0) bei |S Re Re 
Our Asrronomicat CoLuMN :— 
The Observatory of Harvard College, U.S. . . 2 «+ + 326 
Brovocicat Nores:— 
Delicate Test for Oxygen. . . « + ste a,» a ee 
Prothallium and Embryo of Azolla. . a” ey ks ee ie 
Phyllomic Nectar Glands in Poplars . . + «+ + Sey Fe 
Fauna and Flora of the White Sea. . . «© + © : c - 328 
The Growthof Palms . »- . 2 s+» = © © s+ & wo = ® 328 
Acriox or Gases AND Liquips on THE ViTALITY oF SeEDs. By 
Pro€, TTALOIGIGLIOLY =. «. sv. ¥a tela” eipee Wek fan sits a reaee 
Universiry AND EDUCATIONAL INTELLIGENCE - - + «© «© + © * = 
Socimrigs AND ACADEMIES « . + + © © © © © & 
