OcToBER 26, 1916] 
NATURE 
163 
together, occurs at the tapering end of a pair of calci- 
fied cartilages, which evidently represent a jaw. An 
imperfect detached tooth probably belongs to an oppos- 
ing row. The teeth are large compared with their 
base, and the serrated edges have been worn during 
life. Small Orodont teeth of the form named Campo- 
dus are scattered in the shale near the jaw. Mark- 
ings on the Edestus teeth themselves suggest that 
they have been derived from the Campodus type of 
tooth. The specimen was obtained from shale below 
the Rough Rock, in the upper part of the Millstone 
Grit, at Brockholes, near Huddersfield.—A, Holmes : 
The Tertiary volcanic rocks of Mozambique. With 
the exception of a coastal belt of Cretaceous and 
Tertiary sediments, flanked on the west by later Ter- 
tiary volcanic rocks, the territory consists of a com- 
plex of gneisses. and other foliated rocks, intruded 
upon by granites belonging to at least two different 
periods. From Fernao Vellosa Harbour to Mokambo 
Bay the junction of the sedimentary formations with 
the crystalline complex is faulted, and the volcanic 
rocks are distributed on each side of the fault. The 
lavas are of post-Oligocene age, and are the result of 
fissure-eruptions, the feeding channels being exposed 
as small dykes that penetrate the underlying rocks. 
The prevailing lavas are amygdaloidal basalts. An 
andesite dyke of later date occurs near the Monapo 
River. In the north, near the Sanhuti River, picrite- 
basalt, basalt, phonolite, and sdlvsbergite have been 
found, and related lavas occurring elsewhere in the 
area are tephritic pumice and egirine-trachyte. The 
“allali’’ series can be closely matched by the lavas 
of Abyssinia, British East Africa, Réunion, and Tene- 
riffe. The amygdaloidal basalts of the “ calc-alkali”’ 
series are similar to those of the Deccan, Arabia,,and 
East Africa, and also to.those (of late Karroo age) 
occurring in South Africa and: Central Africa. Each 
of the series was probably evolved by a process of 
differentiation acting on a parent magma. From’ the 
composition of the amygdale minerals it is deduced 
that the parent magma of the ‘“‘alkali’’ series was 
rich in carbon dioxide and under-saturated in silica; 
whereas that of the ‘“‘calc-alkali’’ series was rich in 
water and over-saturated in silica. The radio-activity 
of the lavas indicates that the depth from which the 
parent magma came was probably between thirty-three 
and forty-four miles. from the earth’s surface. 
Royal Microscopical Society, October 18.—Mr. E. 
Heron-Allen, president, in the chair.—Dr. Helen Pixell 
Goodrich and M. Moseley: Certain parasites of the 
mouth in cases of pyorrhcea. After a general de- 
scription of the pathological changes in gum tissues 
resulting from pyorrhoea, illustrated’ by sections of 
normal and infected jaws, a detailed account of Enta- 
moeba gingivalis, Gros, was given, followed by notes 
on Trichomonas and the interesting complex Lepto- 
thrix colonies, which give rise to the tartar. Of these 
parasitic organisms only the Leptothrix colonies were 
considered by the authors as likely to be the cause of 
the disease. 
Paris. 
Academy of Sciences, October 2.—M. Camille Jordan 
in the chair.—E. Picard: Functions of two complex 
variables remaining invariable by substitutions of a 
discontinuous group.—G. Bigourdan: The declaration 
of Louis XIII. relating to the first meridian. The 
text of.the declaration, dated July 1, 1634, is given in 
full. The position chosen had no scientific basis.—G. 
Bigourdan: The propagation of the sound of the 
cannonade at the front to great distances. There is evi- 
dence that the sounds heard are not propagated through 
the air, but through the soil.—H.: Douvillé : The Creta- 
NO. 2452, VOL. 98] 
ceous and the Tertiary in the neighbourhood of Thones 
(Haute Savoie).—J. Meunier; The detection of small 
quantities of selenium; distinction from arsenic. 
Selenium may cause error in the Marsh test for arsenic 
when present in minute traces only. A scheme for 
examining the deposit is given, by means of which 
selenium can be detected in the presence of arsenic.— 
P. Garrigou-Lagrange : Luni-solar action and tempera- 
ture.—J. Amar: The technique of the sense education’ 
of men without limbs or sight. Details of the methods 
and apparatus used in the education of the sensibility 
of mutilated limbs, and of the sénse of touch in the 
blind.—L, Camus: Vaccinal immunity resulting from 
intravascular injections of vaccine, 
WasHINGcTon, D.C, ° 
National Academy of Sciences (Proceedings No. 9, 
vol. ii., September 15).—J. Loeb: The mechanism of 
diffusion of electrolytes through animal membranes. 
For the diffusion of certain electrolytes through animal, 
membranes there is required, besides the osmotic pres- 
sure, a second effect, called the.‘‘ salt effect,’’ upon the 
membrane. This consists probably in an ionisation of 
the protein molecules of the membrane.—F. G, Pease : 
The rotation and radial velocity of the spiral nebula 
N.G.C. 4594. The radial velocity is +1180 km., in 
good agreement with the values found by Slipher. 
The linear velocity of rotation at a point two’ minutes 
of arc from the nucleus is more than 330 km.—F. H. 
Seares: A simple method for determining the colours 
of the stars. The method suggested consists in deter- 
mining the ratio of exposure-times which is necessary 
to produce photographic and: photovisual, or, more 
briefly, blue and yellow, images of the same size.—H. 
Shapley ; Studies of magnitudes in star clusters. III. 
The colours of the brighter stars in four globular 
systems. It is concluded that in all the clusters 
examined, and probably in all globular clusters, the 
volumes of the bright red stars are very great in 
comparison with the stars that are fainter and rela- 
tively blue.-—Janet T. Howell: The effect of an electric 
field on the lines of lithium and calcium. Lithium 
and calcium were examined, both for longitudinal and 
transverse effects.—A. B. Coble: A proof of White's 
porism.—J. P. Iddings and E. W. Morley: A contribu- 
tion to the petrography of-the Philippine Islands. Six 
detailed analyses are given of rocks from Luzon, P.I. 
—W..-O. Fenn: Salt antagonism in gelatine. The 
experiments on gelatine support the hypothesis. that 
anions antagonise kations in their effects upon organ- 
isms. The hypothesis here developed resembles that of 
Clowes except that it requires that NaCl should antag- 
onise any electrolyte. which has either-a strong-anion or 
a strong kation. The point-of maximum antagonism is 
an isoelectric point at which the amount of alcohol 
needed for precipitation is at a minimum, and the 
aggregation or amount of precipitation is at.a maxi- 
mum.—W. O. Fenn: Similarity in the behaviour of 
protoplasm and gelatine. .A close analogy to -Oster- 
hout’s: experiments on the electrical resistance of 
Laminaria is found in gelatine (plus NaOH), if we 
assume that the ‘effect of time in the Laminaria. ex- 
periments is to increase the concentrations of the 
salts in the cells of the tissue.—W. E. Milne: Certain 
asymptotic expressions in the theory of linear 
differential equations. Formulas more precise than 
those previously obtained by Birkhoff are given.— 
H. B. Fine: Newton’s method of approximation. A 
condition is given under which Newton’s method of 
approximation for computing a real root of an equa- 
tion, and the extension of this method used in com- 
puting a root of a system of equations, will with 
certainty lead to such a root or solution. 
