52 
[APRIL 1, 1897 
of the medium. By slight alteration of the pendulum-suspen- 
sions this dispersion might be made different at different parts 
of the model, and would then correspond to certain known cases 
of ‘anomalous dispersion.” Or, again, it might be made to 
illustrate the theory of Helmholtz with regard to the vibrations 
of the molecules of glass ; according to which, the vibration 
of the molecules alters the vibrations of the waves, so that dis- 
persion occurs, and the energy is not propagated at the same 
rate as the waves themselves. It was shown by Michaelson 
that it was possible to have a medium in which the energy is 
propagated in one direction, and the wave in another. 
attained, in a magnetic model, by Ewing. 
indicated how a model could be made which should give out 
‘harmonics ” and *‘ over-tones”’ very different from one another ; 
where different wave-lengths would be propagated with different 
velocities, and the over-tones would correspond to the differences 
Further, it indicated a mechanism for producing any desired 
spectrum ; such, for instance, as that of hydrogen. A some- 
This was | 
The mesh apparatus | 
NATURE 
what similar model had been designed by Glazebrook for illus- | 
trating the absorption-bands of a medium when the rate of 
vibration was the same as the free period of the vibrations of 
each of the molecules, which is the theory of Helmholtz, but 
it'was not such a simple model. The experiment of red paper 
changing to black was interesting as illustrating a red spectrum 
varying with temperature.—Mr. Shelford Bidwell proposed 
votes of thanks to all the exhibitors, and the Society adjourned 
until April 9. 
Chemical Society, March 18.—Mr. A. G. Vernon Harcourt, 
President, in the chair.—The following papers were read :—On 
the atomic weight of carbon, by A. Scott. The author calls 
attention to the unsatisfactory nature of the experimental evi- 
dence on which the determinations of the atomic weight of carbon 
rest ; erroneous determinations of the expansion produced by the 
absorption of carbon dioxide by potash solutions have been em- 
ployed. When this and other sources of error have been allowed 
for, the recalculated values of the atomic weight of carbon are 
127008 from the combustion of carbon and 12°050 from the con- 
version of the monoxide into the dioxide.—On a new series of 
mixed sulphates of the vitriol group, by A. Scott. The author 
obtains members of a new series of mixed sulphates of the com- 
position (MN)’’SO,,H,O by adding sulphuric acid to solutions of 
the mixed sulphates ; the ferrous cupric salt Cu,Fe;(SO,),, 7H.O 
is reddish-brown in colour.—A synthesis of camphoronic acid, 
by W. H. Perkin, jun., and J. F. Thorpe. Ethylic B-hydroxy- 
aaB-trimethylglutarate is converted by the usual methods into 
ethylic 8-cyano-acB-trimethylglutarate, COOEt.CMe,.CMe- 
(CN).CH,.COOEt ; this on hydrolysis yields aa§-trimethyltri- 
carballylic acid, COOH.CH,.C(COOH)Me.CMe,. COOH, which 
is found to be identical with camphoronic acid.—Note on a 
method of determining melting points, by E. H. Cook.— | 
Velocity of urea formation in aqueous alcohol, by J. Walker 
and S. A. Kay. . The addition of ethylic alcohol to an aqueous 
solution of ammonium cyanate undergoing conversion into urea 
accelerates the reaction ; if the reverse action and the degree of 
dissociation at the various stages of the process are taken into 
consideration, it is found that the law of mass-dction is strictly 
obeyed. The authors calculate that the conversion of ammonium 
and cyanate ions into urea is accompanied by a heat evolution 
of about 5000 cals. per gram-molecule.—Action of allyl haloids 
on aldoximes and ketoximes, by W. R. Dunstan and E. Gould- 
ing. When formaldoxime, acetaldoxime, and acetoxime are 
heated with an alkyl iodide or bromide in alcoholic solution, 
compounds of the types R’CHN(R’)O and R’,CNCH(R’)O are 
obtained. 
Entomological Society, March 17.—Mr. Roland Trimen, 
F.R.S., President, in the chair.—Mr. Butterfield, present as a 
visitor, exhibited a series of thirty-three male and six female 
LPhigalia pedarza, taken near Bradford, Yorkshire, on February 
14-17, 1897. Twenty-one males were typical in having a greater 
or less development of the four transverse bars. The remaining 
twelve were without bands, and varied in colour from black to 
smoky olive ; they were decidedly less in point of size, ranging 
from I 4° in. to 14/5 in., as against 17 in. to 1+} in. in the banded 
forms, and were also poorer in scales and slightly deformed. 
He had only met with this variety once before in the last twenty 
years, and suggested that the eruption of small, black, and de- 
pauperised forms might have been produced by dryness and want 
of food in the larval conditions, the trees having been exten- 
NO. 1431, VOL. 55] 
sively defoliated in the preceding year.—Mr. Kirkaldy exhibited 
an example of the rare macropterous form of Velia currens, 
Fabr., taken at East Grinstead, and one of Czcadetta montana, 
Scop., from Brockenhurst.—Mr. Burr exhibited a series of grass- 
hoppers with red and blue hind wings, of the family G2dipodide, 
to show the remarkable variation in colour seen in this group. 
Red, blue, and yellow forms are found alike in the same species, 
the blue being due to the failure of the red pigment, and there- 
fore an incipient albinism, the yellow being a further form of 
albinism.—Mr, Champion communicated a paper on the Elate- 
ride and Rhipidoceridze collected by Mr. H. H. Smith at St. 
Vincent, Grenada, and the Grenadines, and exhibited the speci- 
mens.—Dr. Forel also communicated a paper on the Formicidee 
collected by Mr. Smith in the same islands. 
Linnean Society, March 18.—Dr. A. Giinther, F.R.S., 
President, in the chair.—Mr. Bernard Arnold exhibited three 
contiguously-built nests of the chimney swallow, Azrundo 
rustica, having a continuous wall of mud as if built by one pair 
of birds ; but from the evidence of the observer it appeared 
that there were two pairs of birds, and that one pair had made 
two of the adjacent nests. —The Right Hon. Sir John Lubbock, 
Bart., F..R.S., reada paper on stipules, their forms and functions. 
This embodied observations supplementary to those published 
in previous papers (L272, Soc. Journ., Bot. xxviii. 217, and xxx. 
463). It was shown that while the usual function of stipules 
is to protect leaves in bud, in some cases they replace them, and 
in others serve to hold water. Instances were mentioned in 
which stipules developed into spines, and in other cases became 
glandular. Where stipules were absent, other arrangements 
for bud protection were found to exist. Attention was especially 
directed to the formation of the winter buds of certain common 
shrubs and trees, and some curious differences were noted even 
in nearly allied species. In the wayfaring-tree, V2burnem 
Lantana, the author remarked that the young leaves are un- 
covered, but are protected by a growth of hairs; in the ash and 
thorn the outer scales of the bud consist of expanded petioles ; 
in the willow the outer scales consist of leaves; in the poplar 
of stipules. The buds of the oak and beech were also described ; 
and it was shown by the aid of lantern-slides that in the beech 
the outer scales of the bud consist of two pairs of stipules, that 
the twelfth pair are the first which have a leaf, and that the sub- 
sequent growth is between the leaves, while the portion of the 
shoot between the stipules scarcely elongates at all. As a con- 
sequence the seat of each winter bud is marked by a ring, and 
thus.a series of successive rings which remain visible for many 
years indicate each year’s growth.—Mr. W. C. Worsdell read a 
paper on the origin of transfusion-tissue in leaves of gymno- 
spermous plants. It was explained that ‘‘ transfusion-tissue” 
is a special kind of conducting-tissue found chiefly in the leaves 
of conifers, in direct connection with the vascular bundles. 
Evidence was adduced in favour of the conclusion that trans- 
fusion-tissue, as universally found in recent coniferous leaves, 
has originally sprung from the centripetal xylem of the leaf- 
bundle of the ancestors of these plants. 
CAMBRIDGE. 
Philosophical Society, March 8.—Mr. F. Darwin, Presi- 
dent, in the chair.—On the injection of the intercellular spaces 
occurring in the leaves of Z/odea during recovery from _plas- 
molysis, by the President and Miss D. F. M. Pertz. 2/odea 
continues to assimilate in salt solutions strong enough to plas- 
molyse the cells. On replacing the plant in water assimilation 
ceases, the gas disappears from the intercellular spaces, and the 
leaf is injected with water. The disappearance takes place 
partly by the escape of bubbles at the open ends of the inter- 
cellular spaces, but chiefly by solution. The first of these 
phenomena depends on the surface tension of salt solutions being 
greater than that of water. The solution depends on the fact 
that air is less soluble in salt solutions than in water.—The 
phenomena of carbon dioxide production associated with re- 
duced vitality in plants, by Mr. F. F. Blackman. By the aid 
of an apparatus (which was exhibited), specially adapted for 
physiological research on very small outputs of carbon dioxide, 
several new phenomena of this nature have been brought to 
light in plants. These comprise the liberation of carbon dioxide 
produced in the following four cases. Firstly, that resulting 
from the action of temperatures between 40° C, and 50° C. on 
dry resting seeds: at temperatures below 40° C. no appreciable 
