Societies and Academies

Abstract

LONDON

Linnean Society, December 6.—Prof. Allman, president, in the chair.—Messrs. J. N. Fitch, J. S. Gamble, F. S. Piggott, A. B. Stewart, and Prof. Macoun were elected Fellows.—Mr. Thiselton Dyer exhibited portions of the “Nam-mu” tree, which grows in Yunnan, 25°–26° N. lat. The Chinese nobility greatly prize its wood for building purposes and for making coffins, and enormous columns in tombs of the Ming dynasty, 300 years old, are still extant. Supposed to be teak, it probably rather belongs to the Lauraceæ, the leaves closely resembling those of Phœbe pallida. Mr. Dyer also exhibited a seed of Entada scandens, and another of an anonaceoas plant (Cyathocalyx Maingayi?) found in the cœcum of Rhinoceros sumatrensis from Chittagong, and dissected at the Zoological Gardens, Regent's Park; and he likewise showed fruits of Oncocarpus viliensis from the crop of a fruit-pigeon (Carpophaga latrans).—Attention was afterwards called by Mr. Dyer to the fruit-head of an Indian Pandanns made into a brush, the fibrous tissue of the drupes forming the bristles, and this instrument was said to be used to scrape cloth, like our teazle (Dipsacus).—Flowers and foliage of Cinchona (C. calisaya, vars., Josephiana and Anglica) grown in the garden of Mr. J. Elliot, at Tottenham, were exhibited by that gentleman, whose researches among the quinine-bearing trees are already well known and appreciated.—Mr. Moggridge read a note on the occurrence at Wallis Down, a heath near Bournemouth, of Dabeocia polifolia.—A paper on certain organs of the Cidaridæ was communicated by Mr. Chas. Stewart, who illustrated, amongst others, the subjoined points of his recent investigations. Among the sea-urchins the families Diadematidæ, Echinometridæ, and Echinidæ, have long been known to possess external branchiæ; but the existence of such in the Cidaridæ has been denied by Müller, though insisted on by Alex. Agassiz. Mr. Stewart finds in Dorocidaris papillata five organs corresponding to branchiæ, but situated internally. The water bathing these interior gills finds ingress and egress by a crevice near the “compasses,” the peculiar mechanism of the teeth and jaws producing the temporary opening in question. As respects the pedicellariæ of Cidaridæ, where the jaw ends in a terminal hollow fang, there is an additional orifice to that at the tip, besides two glands in the vicinity; he suggests this to be a poison apparatus, comparable to the falces of the spider, and poison sac and tooth of venomous serpents.—The Secretary read a paper by Dr. I. Bayley Balfour, “Observations on the genus Pandanus.” Few families of plants present more difficulty in their elucidation than the Pandanaceæ; this by variability of species, difficulty of procuring the male flower, with little character in the leaves, while tte fruit loses its distinctive features in drying. The Screw-pines had attracted the notice of the early voyagers, but their descriptions are confused. To Rumphius we owe the name Pandanus, though his account and figures are poor compared with Reede's of a century before. Linnæus, though indicating a plant under the name Bromelia sylvestris, omitted the genus Pandanus, a want supplied by his son. Afterwards, as species increased, many new genera were unnecessarily introduced, which Dr. Balfour is now inclined to reject; even Brongniart's New Caledonia genera do not claim acceptance. Pandanus runs over a great breadth of longitude, viz., from east tropical Africa through the Mascarene Islands, India, Indian Archipelago, and Australia, to the Sandwich Islands. The East Archipelago and the Mascarenes are centres whose species do not commingle. There succeeds in this paper other facts and an extensive list of names and references to all the Pandani known.—The substance was given of a report on a small collection of insects obtained by Dr. J. C. Ploëm, in Java, with description of a new species of Hoplia, by Chas. O. Waterhouse, of the British Museum.—The Secretary read a communication by Dr. J. Stirton, viz., “Notes on the Rev. Mr. Crombie's paper on the Lichens of the Challenger Expedition,”and another note by Dr. R. C. A. Prior, relative to the migration of wild geese, purported to have passed from North America to the African coast. Physical Society, December 15.-Prof. G. C. Foster, president, in the chair.-The following candidates were elected Members of the Society:-W. E. Ayrton, J. M. Cameron, J. W. Clark, J. E. Judson, B.A., H. N. Moseley, M.A., F.R.S., Lord Rayleigh, M.A., F.R.S., W. N. Stacker, M.A., and H. T. Wood.-Mr. C. W. Cooke read for the author, Prof. S. P. Thompson, a paper on permanent Plateau films, and exhibited the process of their formation. After a brief enumeration of the various attempts made by Plateau, himself, Schwartz, Mach, Rottier, and others^ most of which are described in the work of Plateau, the author described his own experiment on the subject. As the result of these he concludes that the best films are obtained by using a mixture of 46 per cent, of pure amber-coloured resin, and 54 of. Canada balsam, which should be heated to from 93° to 95° C. The frames for forming the films are made of brass wire o'3 mm,, in. diameter, and when thicker, wire is .employed they are found to be irregular hi consequence of the retention of heat by the metaL The films are obtained by simply introducing these frames into the heated mixture, and they harden almost immediately on exposure tojthe air; but better results are obtained by slow drying in an air bath heated up to 80° C., and allowed to cool. In proof of the toughness of the films it was mentioned that a flat circular film 4 cm. in diameter, had supported a 5O-gramme brass weight at its centre.-Mr. Sedley Taylor then exhibited some experiments in illustration of a paper on the colours exhibited by vibrating liquid films which he has recently communicated to the Royal Society.-Dr. Guthrie exhibited a simple lecture illustration of the action of the telephone. Two similar coils of wire are placed one on the end of a bar magnet, and the other on a soft iron core. A tin disc about three inches in diameter is suspended by two threads almost in contact with one end of this latter, and when a similar disc is brought, at regular intervals, against the end of the magnet which is provided with the coil, a distinct movement of the first-named disc is observed which can be easily increased by properly timing the movement of the inducing disc.