Societies and Academies. 
me Lonpon. 
__ Royal Microscopical Society, December 20.—Prof. 
. J. Cheshire, president, in the chair—J. E. 
. Barnard : ae The ee gee - eee oe 
is suggested for t up of presumably living 
organisms which are aahnliy referred to on filter 
s’’ or “ultra-microscopical viruses.’”” The 
m may be justified on the grounds that such 
organisms are of the same order of size as colloidal 
particles known as sub-microns. Filters are of 
_ variable and often unknown porosity, and it is there- 
fore more satisfactory to let the microscopical limits 
of resolution be the standard beyond which the title 
s ted may be applied. For the investigation 
of ies beyond the limits of microscopical resolution 
but still within the limits of visibility by suitable 
illumination, the improbability of any staining 
‘method proving of value was insisted on, ey 
those involving prolonged fixation processes in whic 
the so-called staining is in reality a deposition of 
‘material on the exterior of the object —H. J. Denham: 
_A micrometric slide rule. When one or more micro- 
_ meter > ecg are employed with several objectives, 
a simple nomograph may be used to convert the 
epiece measurements into known units of length. 
e slide rule described consists of such a nomograph 
fitted with a movable cursor, which is engraved with 
an eyepiece scale enlarged ten times. Oblique rulings 
on the body of the scale represent the rulings of a 
% micrometer. The scale is calibrated by trial 
5 various combinations of eyepiece and objective 
4 ly to be used (at stand tube length) on a 
‘graduated stage micrometer: to use it, the movable 
cursor is set to the predetermined position for the 
combination of eyepiece and objective employed, 
and the eyepiece measurement is read off in terms 
of the stage micrometer, while the magnification 
“may be read off the graduated lower edge of the rule. 
Correction for alterations in tube length without 
recalibration may be made by the help of a second 
nomograph on the back of the slide rule—J. R. 
Norman: Methods and technique of reconstruction. 
‘Some of the methods employed for building up a 
‘model of any object which has previously been cut 
into sections in a definite plane are described. The 
Graham Kerr method consists in making coloured 
drawings of the sections on ground-glass plates ; 
the plates are then fitted together, and a model 
obtained by rendering them transparent by im- 
‘Mersion in a suitable medium. In the so-called 
_** plastic” method invented by Born, which appears 
__ to be in general use, the sections are drawn on plates 
made of some form of wax, their outlines cut out, 
_ and the wax sections fixed together to form a solid 
“model. The technique of preparing the models is 
described and a new wax mixture formulated. 





































ParIs. 
_ Academy of Sciences, December 26.—M. Emile 
& in the chair.—Pierre Termier: The structure 
of the eastern Alps ; origin of the superalpine sheet ; 
the problem of the age of the large strata.— A. Blondel : 
The electro-phonographic method and its use for the 
tion of sounds. The author described in 
.a method of sound recording based on the 
bination of the microphone and oscillograph, 
ind this was modified in 1915 for use under war 
conditions. An imperfect form of this was utilised, 
without acknowledgment, by the French army.—C. 
Guichard : Conjugated networks.—Edouard Imbeaux: 
NO. 2777, VOL. I11] 
NATURE 
103 
The fountain of we Silver Spring). A description 
(with photograph) of Silver Spring, Florida, with a 
geological section showing its relationship with Blue 
Spring, 26 miles distant—Alf. Guldberg: Some 
inequalities in the calculus of probabilities —Bertrand 
Gambier: Linear systems of plane curves admitting 
a given system of bees points.—Georges Bouligand : 
A concept of linear geometry. —Nilos Sakellariou : 
Polar figures.—A. Petot: Motor-cars with transmission 
by a longitudinal Cardan shaft.—M. Maggini: Anoma- 
lous dispersion in stellar spectra. Studies on anoma- 
lous dispersion may serve as a qualitative test of 
the theories of Lockyer and Schuster on the evolution 
of stars.—J. Le Roux: Newton’s mechanics is not 
an approximation of that of Einstein.—F. van Aalst : 
The maintenance of electrical oscillations by a lamp 
with three electrodes. Experiments confirming the 
formula expressing the necessary condition for the 
maintenance of oscillations—A. Druault: The dif- 
fraction spectra produced by round corpuscles 
irregularly distributed. Three classes of round 
corpuscles were used in these experiments, lyco- 
podium grains, powder from diseased wheat, and red- 
blood corpuscles. The existence of a maximum of 
diffracted light not predicted theoretically is shown.— 
H. Weiss and P. Henry: Diffusion in solid solutions. 
A study of the interdiffusion of gold and silver at 
temperatures of 935° C., 885° C., and 835° C. The 
diffusion constant found agrees well with the earlier 
figure of Fraenkel and Houben at 870° C.—F. 
Bourion and E. Rouyer: The application of the 
method of continuous variations to boiling - point 
phenomena for the determination of double salts 
in solution.—Marcel Delépine: The cis and trans 
iridio-dichloro-dioxalates. The optical resolution of 
the cis potassium salt.—Marcel Godchot and Pierre 
Bedos: The oxide of A;-methylcyclohexene and 
the dimethylcyclohexanols. The ether oxide can be 
obtained from the hydrocarbon A,-methylcyclohexene 
either by direct oxidation with perbenzoic acid or by 
conversion into the iodohydrin and subsequent treat- 
ment with caustic potash. The ether’ oxide is con- 
verted into the corresponding diol by heating with 
water for six hours at 130° €-—Paul Gaubert: The 
polymorphism of antipyrine, vanillin, and the eryth- 
rites—M. Lecointre: The paleozoic strata of the 
region north-west of Zaér (Western Morocco).— 
Georges Corroy: The Valanginian of the eastern 
border of the Paris basin.—M. Boit : The morphology 
of the Bas-Morvan.— Marc Dechevrens: Two cate- 
gories of earth currents. A discussion of various 
observations from 1851 onwards from the point of 
view of the influence on the moon on telluric currents. 
—C. Dauzére: Researches on natural coloration 
effected at the Pic du Midi according to the experi- 
ments of J. Bouget. The intense colorations of 
flowers at high altitudes are ascribed to the same 
cause as the permanent coloration of glass exposed 
in similar positions.—Ph. Flajolet: Perturbation of 
the magnetic declination at Lyons during the year 
1921—22.—R. Dongier: Magnetic measurements in 
the south-east of France (left bank of the Rhéne).— 
L. Blaringhem: Hereditary mosaic in the pea (Pisum 
sativum).—René Souéges: The embryology of the 
Malvacee. The development of the embryo in 
Malva rotundifolia.— E, and G. Nicolas: The in- 
fluence of formaldehyde on the higher plants. When 
chlorophyll is absent, or present in insufficient 
quantity, formaldehyde exerts a toxic action on 
plants: when the chlorophyll can act as a photo- 
catalyst the influence becomes favourable to growth. 
—Manuel Sanchez y S&nchez: The nature and 
function of the reticular apparatus of Golgi. The 
process of oxidation in the plant cell and the de- 
velopment of the network of Golgi increase together ; 
