Marcu 28, 1907 | 
NATURE 
8 formes locales, qui ont toutes dans leur dérivation un 
caractére malgache; trois formes locales (sous-espéces ou 
variétés) dérivées d’espéces indomalaises; une espéce 
océanienne ; une espéce américaine évidemment importée et 
ayant un peu varié; puis deux formes communes aux archi- 
pels mais l’une au moins décidément dérivée malgache. 
Enfin, une espece (Pheidole punctulata) et une sous-espéce 
(Camponotus grandidiert) tout communes aux faunes afri- 
caine et malgache, probablement dérivées de la premiére.— 
(7) Pyenogonida: Prof. G. H. Carpenter. Only five 
species of the group were obtained, of which four are de- 
scribed as new. The most remarkable is a Colossendeis 
from 450 fathoms off the Saya de Malha Bank.—(8) Aves: 
Dr. H. F. Gadow, F.R.S., and J. Stanley Gardiner. 
The birds obtained were in no way remarkable, being 
mostly waders or regular sea-birds of wide distribution. 
The crab-plover (Dromas ardeola) was found everywhere. 
Of economic importance as guano-formers were breeding 
colonies of Fregata ariel on Nelson Island, Chagos, Sula 
piscator on St. Pierre, Sterna fuliginosa and Anous leuco- 
capillus on Cargados Carajos, and Pelecanus crispus and 
Puffinus tenutrostris on St. Joseph, Amirante Islands. 
Society of Chemical Industry, March 4.—Mr. R. J. 
Friswell in the chair.—Five years’ experience in measuring 
and testing producer gas: R. Threlfall, F.R.S. The first 
part of the paper is devoted to a réswmé of the principles 
and construction of the instruments employed in Pitot tube 
gas measurement. This is followed by a description of the 
** static ’? method of measuring gas density. An account is 
then given of the results of balancing the make and distri- 
hution of producer gas over a period of several years, this 
being illustrated by curves which show that an agreement 
within about 2 per cent. can be attained in practice. The 
next section of the paper is devoted to a discussion of the 
theory and practice of measuring pulsating streams of gas 
or air, such, for instance, as are produced by pumping by 
gas-engines or otherwise. As to the question of sulphur in 
producer gas, it is shown that the referee’s test is less 
suitable for this purpose than a modification of Valentine’s 
test. The discussion of this matter covers both the deter- 
mination of sulphuretted hydrogen and of total sulphur, and 
it is shown that it is fatal to the sulphuretted hydrogen to 
employ a gas meter containing water—no matter how long 
it may have been in action. The best methods hitherto 
proposed and practised for the determination of the volume 
of gas produced per ton of coal, otherwise than by the 
author’s meters, are considered critically, and some ex- 
amples are given of the results of balancing on carbon and 
On ammonia. The paper ends with a note on the deter- 
mination of producer temperatures by a system of thermo- 
couples which are read by a potentiometer suitably divided 
to read direct, and fed by a very large Clark or cadmium 
cell. 
Zoological Society, March 5.—Mr. F. Gillett, vice- 
president, in the chair.—The discovery, in cave deposits in 
Crete, of remains of elephants, some of which represent a 
new species: Miss D. M. A. Bate.—Report on the Polyzoa 
of the third Tanganyika expedition: C. F. Roussetet. 
Five species were represented in the collection, three. of 
which were described as new. Of the five species, three 
belonged to the Phylactolamata and two to the Gymno- 
lamata. Amongst the latter was Arachnoidita raylankes- 
tert, Moore, which was found in some abundance on shells 
dredged from deep water.—Report on the Brachyurous Crus- 
tacea of the third Tanganyika expedition: Dr. W. A. 
Cunnington. The collection contained specimens from 
both Nyasa and Tanganyika. Including a few individuals 
which had hitherto passed without notice in the collection 
of the British Museum, there were now on record three 
species from Nyasa and five from Tanganyika. Of these 
species, three were described as new. The forms from 
Nyasa all belonged to the widely distributed subgenus 
Potamonautes ; but while two species from Tanganyika 
also belonged to that subgenus, the lake contained three 
species belonging to the remarkable endemic genus Platy- 
thelphusa, A. Milne-Edwards. The suggested marine ap- 
pearance of P. armata was considered to be only super- 
ficial, and the peculiar character of the Brachyuran fauna 
of Tanganyika could be explained on the grounds of a 
NO. 1952 VOL. 75] 
prolonged isolation of the lake.—Two new species of 
African oligochate worms of the genus Microchztus be- 
longing to the collection of the Christiania Museum: F. E. 
Beddard. 
Physical Society, March 8.—Prof. J. Perry, F.R.S., 
president, in the chair.—The rate of recovery of residual 
charge in electric condensers: Prof. F. T. Trouton and 
S. Russ. The experiments described by the authors were 
undertaken in order to examine the rate of recovery of 
residual charge when the difference in potential of the 
plates is kept constant. Previous experimenters have 
always allowed the charge to accumulate on the plates 
while observing the rate of rise in potential. In that case 
the recovery meets with an ever-increasing opposition 
which complicates matters. The authors have employed 
two methods. 
In the first, which was used with mica 
condensers, the potential, observed by an electrometer, 
was kept constant by means of a variable resistance 
which was gradually increased as the recovery current 
diminished. The high resistance necessary was con- 
structed of two horizontal metal plates with ionised air 
between them. A movable shutter could be introduced 
between the plates to diminish gradually the cross-section 
of the air resistance as required. The second method 
was used when the residual charge was great enough. In 
it the current was passed through a dead-beat galvano- 
meter, and the value of the recovery current at each 
moment determined. In this case the difference of poten- 
tial of the plates may be taken as constant since it was 
practically zero. Lhe observations when plotted with 
current against time were found to lie on a hyperbola. 
This shows that in the circumstances of the experiments 
the quantity of electricity recovered up to any given time 
follows a law QO=alog(p+t) similar to that found by 
Rankine and others for the recovery of stress in over- 
strained elastic bodies when the strain is kept constant. 
MANCHESTER. 
Literary and Philosophical Society, February 12,— 
Mr. Francis Nicholson in the chair.—Some tables for ex- 
plaining the nature of statistical correlation: A. D. Darbi- 
shire. The thirteen tables exhibited graphically the results 
of thirteen series of pairs of throws of dice in such a way 
that the effect of increasing the correlation between the 
first and second throws of the pair was clearly seen. The 
method is an application, to some new sets of throws, of 
Weldon’s beautiful device for illustrating statistical cor- 
relation. 
February 26.—Prof. H. B. Dixon, F.R.S., in the chair.— 
Report on the recent Foraminifera from the coast of the 
Island of Delos (Grecian Archipelago), part iv.: H. Side- 
bottom. Drawings of some of the more interesting species 
were exhibited, and mounted specimens were shown under 
the microscope.—The leaves of Passerina: Madeline 
Carson. The Passerine belong to the natural order 
Thymelaaceze. These plants inhabit the warm dry regions 
of Egypt, South Africa, and the Mediterranean. They are 
common on the sand hills near the coast, and always live 
under conditions in which there is a difficulty of obtaining 
water. In order to combat against this, they are specially 
modified. The leaf surface is reduced, often the leaves are 
imbricating. They are provided with a very thick cuticle, 
have the edges inrolled, and the stomates are found only 
on the inner surface. They are further protected by a cover- 
ing of hairs. The chief object of the study of these leaves 
was to discover whether the epidermal cells contained 
mucilage or not. In Passerina filiformis and in P. 
hirsuta, the author found that in many of the epidermal 
cells a portion was cut off from the rest by a cellulose wall. 
The upper portion contained tannin and probably mucila- 
ginous sap, while the lower portion consisted of hard 
stratified mucilage. In the other species examined, Pas- 
serina ericoides and PP. rigida, no trace was found 
of separation of the epidermal cells into a striated and non- 
striated portion. The whole epidermal cell stained with 
mucilage stains and tannin stains. Since mucilage and 
tannin both act in the same way towards methylene blue, 
and since it is impossible to separate tannin and mucilage, 
the evidence for the presence of mucilage in these species 
is not perfectly conclusive. As, however, mucilage is with- 
