APRIL 15, 1915 | 
NAT ORE 
195 


it was shown that trails of vortices following in the 
wake of a body moving through a fluid did not form 
a stable system, so that the theory recently advanced 
by Karman, which was based upon a suggestion made 
originally by Kelvin, did not seem to be tenable. The 
paper also contained an interesting development of 
the method of finding the stream lines with certain 
definable forms of boundary.—F. D. Miles: The 
electrical conductivity of aqueous hydrochloric acid, 
saturated with sodium chloride; and on a new form 
of conductivity cell. Within the range of concentra- 
tion (15 to 27 per cent. of hydrogen chloride) the 
specific conductivity is lowered by saturation with 
salt. The salt-saturated acid of maximum conduc- 
tivity was prepared by adding salt to a solution con- 
taining 21-9 per cent. of hydrogen chloride, whereas 
the best conducting solution of hydrogen chloride 
alone contains only 19-1 per cent. of that substance. 
The conductivity cell described was specially suitable 
for solutions which are saturated or contain volatile 
constituents.—F. D. Miles: The reaction between 
sodamide and hydrogen. At temperatures near to 
250° C. these substances react according to the 
formula, NaNH,+H,=NaH+NH;. 
March 15.—Prof. Bower, vice-president, in the chair. 
—Dr. J. H. Ashworth: The larve of Lingula and 
Pelagodiscus. Sixteen larve of Lingula anatina were 
taken by him last year in the surface waters of the 
southern part of the Red Sea, and one in the Indian 
Ocean about 4° south of Colombo. The latter is 
noteworthy because of the depth of water (2200 
fathoms) in the locality where the larva was taken. 
The larve varied from o5 to 16 mm. in length. 
Descriptions were given of the alimentary canal, 
calomoducts (nephridia), and statocysts, and of the 
changes in shape of the shell valves as growth pro- 
ceeds. An account was also given of the anatomy of 
the larva of Pelagodiscus (Discinisca) atlanticus, 
based on six specimens, about 0-4 mm. in length, 
which were taken in October last a few miles west 
of Cape Cormorin in water of 40 fathoms. Adult 
specimens of this Brachiopod have almost entirely 
been recorded from deep water. Blochmann has 
denied the presence of statocysts in both Lingula and 
Pelagodiscus, but these organs were certainly present 
in both genera.—C. Cochrane: The reflective power of 
pigments in the ultra-violet. The diffuse reflection 
from the prepared strip of pigment, which was illu- 
minated by a complete iron-are spectrum, was photo- 
graphed, a similar photograph of the reflection from 
a contiguous strip of white cardboard being simul- 
taneously taken as a standard of comparison. More 
than thirty different pigments were experimented with, 
and of these the greater number showed selective 
reflection in the higher ultra-violet. There were, 
however, marked exceptions, such as Chinese white, 
the reflective power of which rapidly diminished as 
the wave-lengths became shorter.—Dr. W. T. 
Gordon: Archzocyathinae collected by the Scottish 
National Antarctic Expedition. The specimens were 
obtained in a block of limestone dredged in the 
Weddell Sea, and associated with them were remains 
of calcareous alge and sponges. The Archzo- 
cyathine can be grouped under the genera Archzo- 
cyathus, Spirocyathus, Coscinocyathus, Syringocnema, 
and Protopharetra. The fauna shows striking simi- 
larity with that described by Taylor from the Cam- 
brian rocks of South Australia. 
Paris. 
Academy of Sciences, April 6.—M. Ed. Perrier in the 
chair.—G, Bigourdan: The instrumental undulations 
of images; their daily and annual variation and their 
NO. 2372, VOL. 95| 

relation with the general state of the atmosphere. 
A discussion of the causes and means of elimination 
of the irregular movements of the focal images of 
stars.—Paul Appell: The approximate inversion of 
certain real integrals, and on the extension of 
Kepler’s equation and Bessel’s functions.—L. E. 
Bertin: Calculation of the increase of velocity or of 
range of submarines resulting from increase of their 
dimensions. Data furnished by ordinary vessels are 
not directly applicable to submarines. It would 
appear that the maximum speed and range will be 
reached for a submarine having a displacement at 
the surface of 1000 tons.—Maurice Hamy: Radio- 
graphy in the hospital at the Institute. Radiographs 
of all the wounded are made as they enter the hos- 
pital in the same attitude on two distinct plates, the 
bulb being moved a distance of 7 cm. The nega- 
tives, examined in a_ specially constructed stereo- 
scope, show the position of the metallic fragment or 
damaged bone in relief, by means of which the 
operation is much simplified—M. Guignard; The 
formation of pollen.—J. Bosler: The rotation of the 
solar corona. Measurements of the red line of wave- 
length 6374-4 on the east and west borders gave by 
the application of the Doppler-Fizeau principle a 
tangential velocity of 3-7 kilometres per second, with 
a possible error of 25 to 30 per cent. This agrees 
well with the determination of W. W. Campbell, 
who by applying the same method to the green line 
5303 obtained a velocity of 371 kilometres per second. 
Hence the corona moves in the same sense as the 
direction of movement of the sun, and apparently 
with a higher velocity.—H. Deslandres: Remarks on 
the preceding communication and on problems con- 
nected with the rotation of the solar corona, The 
study of the corona throws light on the important 
question of a corpuscular radiation emitted by the 
sun and received by the earth, but increase of know- 
ledge in this direction must necessarily be slow, since 
the corona is only observable during eclipses.—Daniel 
Berthelot : The temperature-coefficient of photochemi- 
cal reactions. For the changes studied, the decom- 
position of lavulose and the decomposition of a mix- 
ture of oxalic acid and ferric chloride the rate of 
photochemical change is increased by a rise of tem- 
perature, but the coefficient is very much smaller than 
that of an ordinary chemical change.—Henri Coupin : 
The resistance of marine bacteria to the action of 
salt. Marine bacteria have tolerance for a consider- 
able range in the proportion of salt in the water in 
which they develop, as they can support 8 per cent., 
and are content with as little as 0-3 to o'2 per cent. 
They adapt themselves better to proportions lower 
than the normal sea-water salt-content than to more 
concentrated solutions.—C. Sauvageau; The develop- 
ment and the biology of Saccorhisa bulbosa.—J. 
Bergonié : The detection and localisation of magnetic 
projectiles by an electromagnet actuated by an alter- 
nating current. The vibration of the flesh immedi- 
ately over the metallic fragment gives an accurate in- 
dication of its position. Details are appended of 
several operations successfully carried out by this 
means.—MM. Belot and Maxime Ménard: The use of 
the Coolidge tube in the medico-surgical applications 
of the X-rays. The Coolidge tube is based on the 
discharge of independent electrons and details are 
given of a pattern made in France by Pilon. _ The 
advantages obtained, as compared with the ordinary 
tube, are the regularity in working, the long period 
of regular working, the possibility of regulating the 
tube without modifying the vacuum, the fixed point 
of impact on the kathode, and the homogeneity of the 
bundle of X-rays.—Miramond de Laroquette and 
Gaston Lemaire: Tables of the coefficients of magni- 
