212 
NATURE 
[Dec. 29, 1881 
commonly cultivated in tropical Africa ; though along the Nile 
valley G. herbaceum is that usually in cultivation, According 
to authorities, cotton was not cultivated in Egypt in ancient 
times, and the fact that the varieties now grown there are for the 
most part forms of G. herbaceum, suggests the idea that India is 
the source whence Egypt has derived the cotton—a notion con- 
firmed by various other considerations, The wild form of GC. 
herbaceum, Dr. Masters has previously shown, is probably G. 
Stocksit, Masters, a native of Scinde.—A note on Adies Pattonii, 
Jeffrey, MS. 1851, by Prof. W. R. McNab, was then read. The 
author mentions that the trees known as 4. Hookeriana and A. 
fattonit have been a source of confusion to botanists and horti- 
culturists. Andrew Murray, in 1855, in describing a New North 
American pine, mixed up the leaf of 4. Patfonit, Balf., from 
Mount Baker, with the cone of 4. Hookeriana from Scots Moun- 
tain, Oregon, originally collected by Mr. John Jeffrey. Dr. 
McNab, in unravelling the error, proposes that as Jeffreys, No. 
430, from the Cascade Mountains, named by Balfour 4. Patéonit, 
in the Oregon Circular, was unpublished, it should now be re- 
ferred to 7suga Hookeriana, and the Mount Baker tree he re- 
garded as 7, Pattoniana.—There followed a paper by Dr. G. 
EE. Dobson, on the digastric muscle, its modifications and func- 
tions ; and thereafter the eleventh part of the Mollusca of the 
Challenger Expedition, by the Rev. R. Boog Watson, was read 
in abstract.—Messrs. W. H. Coffin, E. Milner, and S. H. 
Parkes were balloted for and elected Fellows of the Society. 
Mineralogical Society, December 14.—W. H. Hudleston, 
F.G.S., President, in the chair.—Messrs. H. Baker, F.C.S., 
and R. Fleming, were elected Members.—The following paper 
was read:—On some minerals from the sodalite syenite of 
Julianshaal District, South Greenland, by Johann Lorengen ; 
communicated by Prof. Johnstrup.—Mr. Baring Gould and Mr, 
Porter Rhodes, who were present as visitors, gave an account of 
the diamond mine of Kimberley, South Africa, illustrated by 
photographs of the workings and by numerous specimens, which 
gave rise to an interesting conversation. 
PARIS 
Academy of Sciences, December 19.—M. Wurtz in the 
chair.—The following papers were read :—Proofs of the recent 
formation of the Mediterranean, by M. Blanchard. In the 
nature and relations of plant species in places more or less apart 
he seeks evidence regarding changes that have occurred in the 
configuration of the land. Were the banks of the Mediterranean 
brought together one might pass from Europe into Africa or into 
Asia without any trait of nature making one aware of it. Now 
as very moderate obstacles prevent a dissemination of many 
plants and animals, the Mediterranean would be absolutely un- 
crossable by most living species. It is inferred that the sea has 
been formed in the present age of the earth, when the animals 
and plants on the coasts were under the same conditions as now. 
The recent study of the marine fauna, proving that there are few 
species in the depths, and those present are probably from the 
Atlantic, is thought confirmative. M. Milne Edwards con- 
sidered the uniformity of natural productions explained rather 
by the recent existence of two isthmuses between the northern 
and southern banks of an older sea, one between Sicily and 
Tunis, the other between Spain and Morocco. The Mediter- 
ranean has probably not been in communication with the Indian 
Ocean since the Miocene epoch. M. Daubrée also declined, on 
geological grounds, to accept M. Blanchard’s conelusion.—Ob- 
servations on the decomposition of metallic formiates in presence 
of water, by M. Berthelot.—On the principle of surfaces of 
separation, by the same,—M. de Lesseps presented maps and plans 
of the project of a railway between the Niger and theSoudan, by 
the Fonta-Djallon. The Fonta-Djallon presents a central plateau 
350 km. from the coastand rooom, in altitude ; five parallel val- 
leys run from it to the coast. The iman of Timbo (in that region) 
is friendly.—Researches on the fundamental laws of electro- 
dynamics, by M. Le Cordier, This mathematical memoir was 
deposited as a sealed packet in September.—On a means of 
preventing the development of phylloxera by turfing the ground 
In the intervals of the vine-stocks, by M. Bidauld. This proposal 
is based on the facts that heating of the ground is very favour- 
able to hatching of the apterous, and still more of the winged 
pbylloxera, and that according to MM. Becquerel, bare ground 
requires in summer a much higher temperature than turfed 
ground.—Ephemerides of the planet (217) Eudore (continued), 
by M, Callandreau.—On the introduction of logarithms in 
criteriums, which determije an upper limit of the number of 
roots of an equation which are comprised between two given 
numbers, by M. Laguerre.—On a. differential equation of the 
form /) G a)= o, by M. Fuchs.—On functions irreducible 
Z 
according to a prime modulus, by M. Pellet.—Theorem of 
arithmetic, by M. Weil.—Amplitude of diurnal oscillation of 
the magnetic declination obtained at the Observatory of the 
Charles Albert Royal College, at Moncalieri, in the years 1879 
and 1880, by M. Denza. In agreement with previous data — 
(1871-78) the minimum occurs in the winter months, and the 
maximum in summer, The values for the summer months are 
very variable. The mean annual values for the two years are 
both superior to that for 1878, which, indeed, is the smallest in 
the period 1870-1881 ; the minimum seems to have been passed 
then, or rather between 1877 and 1878.—On the method of M. 
Lippmann for determination of the ohm, by M. Brillouin,— 
History of the process.employed for direct coppering of cast 
iron, by M. Weil. He maintains his rights and priority in 
the invention. His patents date from 1863.—On the diffusion of 
solids in solids, by M. Colson. When, eg. in a reducing 
atmosphere, an iron plate is heated in lampblack, not only 
does carbon pass into the iron, changing it successively into steel 
and cast iron, but notable quantities of iron are diffused in the 
carbon, This will occur at a temperature below red. At a low 
temperature the iron is more easily diffused in the carbon ; at a 
high, the reverse is the case. Nothing of the kind occurs with 
platinum. For two solids to diffuse into each other, there must 
be affinity, or more generally, they must react on each other. 
M. Colson illustrates this, and he describes an experiment esta- 
blishing the law of the diffusion.—On the temperature of com- 
bustion, and on the dissociation of carbonic acid and of aqueous 
vapour, by MM. Mallard and Le Chatelier.—On chromocyanide 
of potassium, by M. Moissan.—On the decomposition of metal- 
lic formiates in presence of water ; production of some crystal- 
line mineral species, by M. Riban.—On a new sub-class of 
Infusoria, by Mr. Geddes. This relates to curious, small, 
curved, pear-shaped cells found in the mesoderm of the Planarian 
Convoluta ; they have a large central vacuole, and in the wall of 
this a row of fibrillee, which, when the cell is in water, are in 
rapid rhythmic contraction, altering its shape. When in the 
animal’s body, the cell shows but slight contraction. The author 
thinks these cells parasitic infusoria, and proposes for them the 
name Pulsatella convolute ; a fourth sub-class, Pu/satorians, being 
here represented.—On a new type of Turbellaria, by M. Silli- 
man. This was got at Roscoff; it is parasitic ona green parasitic 
nematoid. It is intermediate between Turbellaria and Trema- 
toda, and the author proposes to call it Sydesmis. The genital 
organs are the most remarkable character.—On the live fishes, 
crabs, and molluscs ejected by the Artesian wells of the Oued 
Rir (Sahara of the province of Constantine), by M. Rolland. 
These animals are only for a time under ground in passing from 
one ‘‘bahr ” or pond to another.--On the age of the carboni- 
ferous limestone of the Central Oural, by M. Grand Eury.— 
Two posthumous memoirs of M. Delesse were presented: one 
on the influence of soil on the composition of the ashes of plants, 
the other on the waters of Savoy. 
CONTENTS 
Suicipz. By Gseorce J. Romangs, F.R.S. . . « « » © 
Our Book SHELF :— 
Wheeler and Smith’s “‘ Catalogue of the Phznogamous and 
Pace 
193 
Cryptogamous Plants of Michigan” . . . . yea 196 
LETTEKsS TO THE EDITOR :— 
Pendulum Observations in London.—Major J. HerscHeL . . . 196 
Dante and the Southern Cross.—Signor N. Perinr. .« eee / 
The Horse-Power given to any Part of a Circuit by Intermittent 
Light.—Joun Perry (With Diagram) . . . «© « «© « « « 198 
The New Red Star in Cygnus.—J. BirmMInGHA of 8) jee Lepie Satee 
Meteor —Rey. JouN Hoskyns-ABRAHALL eretiee yy oc 
A New Ececrricat SroraGe Barrery. By Henry Surron. . . 198 
Tue BiscHorrsHemm OssERVATORY. om ee ele 6 ve) tbl 
Fossit FrokA OF SUMATRA 500 «ss 3 pe ahs) eee ee 
Tue VoyaGE oF THE ‘‘ VgGa,”’ II. (With [dlustrations) . . . + . 200 
Nore. ibaee tee ee ietas, whe ise Cee) ena) oe ores 206 
Our AsTRONOMICAL COLUMN :— 
‘The Satellites of Mars. . .. . ove & ih «piealt sets ac eee 
Comet 1881 ¢ (Swift, November 16) ° 18) aes § ey ny 
The Comets of Short Period. . . « . 209 
Variable Stars . <i One ate 209 
GrocrapHican NoTES . . . . . + + e 209 
Dr. LENZON THE SAHARA . . 6 « © «© © 8 210 
Screnrmic SshrArs’. «3. se =) 6 «6 se ee el © 210 
Socigrims AND ACADEMIES . . . « © 6 « 0 e%s e 6 6 © s OEE 
