Societies and Academies

Abstract

EDINBURGH. Royal Society; July 8.—Dr. J. Home, president, in the chair.—Dr. R. Kidston and Prof. W. F. Lang: Old Red Sandstone plants, showing structure, from the Rhynie chert bed, Aberdeenshire. Part ii. Additional notes on Rhynia Gwynne-Vaughani, Kidst. and Lang; Rhynia major, n.sp.; and Hornea Lignieri, n.gen. et sp. In this paper the species of Rhynia, which were included under one name in a former account, are distinguished as R. Gwynne-Vaughani and R. major. The latter plant is larger in all its parts, and lacks the adventitious branching found in R. Gwynne-Vaughani; but its morphology is essentially similar. Both plants are rootless and leafless. They have a subterranean rhizome with a simple stele, erect branched cylindrical shoots, and terminal sporangia. Another plant of similar organisation is named Hornea Lignieri, and is united with Rhynia in the family Rhynaceæ. It also had neither roots nor leaves. The subterranean rhizome was protocormus-like, and from it erect dichotomous stems arose. At the tips of some of these were developed sporangia, which differed from those of Rhynia in having a colurrtella of sterile tissue, making the spore-sac dome-shaped.—A. G. Ramage: Notes on mirage observed on the Queensferry Road. Under the conditions of a strong sun and not too strong a breeze, apparent reflections of grass and passing vehicles were observed in the highly heated surface of the bitumenised road. It was necessary to stoop so as to bring the mirage phenomenon over the surface into view. Sometimes a silvery streak was observed. The author did not find, the usual theory of mirage sufficient, and suggested the reflection from a swarm of small particles as a vera causa.—Dr. W. W. Taylor: (1) The rotatory commutator method of determining electric conductivity, and an improved form of Mac-Gregor's drum. This drum is a double reversing key, reversing the current continuously so as to make it alternating through the electrolyte, and readjusting it so as to make it continuous through the galvanometer. It is well known that with the usual form of drum the apparent resistance varies with the conditions, such as the rate of rotation, and differs slightly from the value obtained by the Kohlrausch method. These defects are due to the construction of the drum, and by a simple modification the defects have been overcome. (2) The solubility of insoluble salts and of silver oxide. There are large discrepancies between the solubility of these substances as determined by chemical analysis and physical methods, the latter depending on the determination of the concentration of an ion. The chemical methods give always the greater values owing to the presence of “sols” of the substance in addition to the true solution. In the case of silver oxide a yellow-brown solution was on one occasion obtained; yet its total amount was less than in a similarly prepared colourless solution. In like manner, the increased solubility of insoluble salts in presence of substances like starch is to be attributed to the protection of the sol by the emulsoid, and not to adsorption at the interface. {3) The electric conductivity of sols. A series ctf determinations of the electric conductivity1 of Kohlschütter's silver sol led to the conclusion that the small limiting conductivity is dependent on the electrolvte “impurity” derived from the substances emploved in the preparation of the sol. (4) The titration acidity of urine. The estimation of the acidity of urine by titration with alkali and phenolphaleins: ootassinm oxalafe is added “to remove the calcium which interferes with the end-point.” Experiments show that the end-point is the same in the absence of the oxalate, though perhaps it is not auite so easily fixed. The addition of neutral calcium chloride is found to increase the acidity to a certain definite extent, and this increased acidity is removed by neutral potassium oxalate. It has not yet been ascertained to what constituent of the urine this is due.—R. A. Fisher: The correlation of relatives on the supposition of Mendelian inheritance. The general conclusions of this mathematical investigation are:— (1) The facts of biometry do not contradict, but in manv cases positively support, the theorv of cumulative Mendelian factors: (2) if the theory is correct, a sufficient knowledge of the correlation coefficients for any one feature, between different pairs of relatives, would enable us to analyse completelv and estimate numerically the percentage due to heritable factors; (3) a provisional examination of the existing data shows it to be quite unlikely that more than 5 per cent, of the variance of the physical measurements of man is due to non-heritable causes.