All methods of vapour density determination hitherto in use, in which quartz or glass manometers are employed, suffer from the disadvantage that the highest temperature attainable is about 750° C.

It is, however, possible to overcome this difficulty whenever the substance under investigation has a considerable vapour pressure below 750° C.

Hydroid Zoophytes were collected by the Nimrod at eleven different stations within the Antarctic Circle. These stations centre round three definite areas of Victoria Land—the open waters of M'Murdo Sound to the west and north-west of Cape Royds (“M'Murdo Sound” in the following pages); the open waters of the Sound from Cape Royds southwards (“Cape Royds” in the following pages); and the Bay, a small indentation in the land to the east of Cape Royds.

The absorption spectra of aqueous solutions of ferric chloride have been examined qualitatively by Jones and Anderson, and quantitatively by Ewan, but Ewan's measurements were confined to very dilute solutions. It was thought, therefore, that quantitative measurements might profitably be carried out on more concentrated solutions of ferric chloride and on solutions of other salts of iron.

The salts experimented on in this research were the chlorides, bromides, nitrates, and sulphates of copper, cobalt, and nickel. They were obtained from Kahlbaum. Jones and his co-workers have already investigated qualitatively the absorption of alcoholic solutions of some of these salts. Also quantitative measurements of the absorption at a few points in the visible spectrum have been made by Vaillant for some of the hydrated salts. In the present case solutions of the anhydrous salts were examined.

My last communication in reference to the history of axisymmetric determinants dealt with the period 1841–1859 (Proc. Roy. Soc. Edin., xxvii. pp. 135–166). The present paper continues the history up to the year 1880, but in addition contains an account of one contribution belonging to the previous period, namely, by d'Arrest (1857).

It is well known that salts such as the chlorides of the alkali metals are less soluble in water containing the corresponding acid than in water alone; and for sparingly soluble salts, in weakly acid solution, the decrease of solubility has been shown to follow quantitatively the course predicted from simple ionic notions. With concentrated solutions of strong electrolytes, however, the causes which operate are still obscure; and, indeed, much has yet to be discovered as to the facts in such cases. There may be said to be two methods of studying the isothermal phenomena in question. The first, which has received attention from numerous observers, consists in determining the solubility of a salt in water containing the acid in varying concentrations. This may be termed the “solubility“ method. The second method seeks to ascertain the minimum concentration of aqueous acid which must be used in order to cause deposition of salt, when the acid is added in small quantity to the saturated aqueous salt solution. This we shall refer to as the “precipitation“ method; it was adopted by Gibson and Denison, and formed the subject of a communication by them to this Society (Proc., vol. xxx., 1910, p. 562).

In a previous paper by one of us, it was shown that a certain part of rock magnetism was variable and uncertain under the influence of raised temperature. In some instances the rock specimen became permanently more magnetic after it was heated in air, whereas, in the majority of cases, heating caused great loss of magnetic quality. It was suggested that the increase of magnetism observed was caused by the transformation of hæmatite into a more magnetic iron oxide.

In order to obtain material which might support this assumption, and also to amplify the work of previous investigators, experiments were undertaken with artificial and natural ferric oxide, in which the transformation of ferric oxide from a non-magnetic into a magnetic condition was observed, while some of the conditions which assist or impede this change were also studied.

The immediate purpose of this research has been:—

1. To investigate whether a presumably spontaneous growth variation amounting to a four-day rhythm which had been observed in certain organs of limited growth was an individual idiosyncrasy or was of general occurrence in plants.

2. To examine the growth rhythm in roots and ascertain if any correlation existed between the respective rhythms of root and shoot in the same plant.

All instruments designed to give a record of some fluctuating quantity as a function of the time, both those employed to give “instantaneous” values of the quantity measured and also those which totalise or integrate it during a given time, are liable to sufler from error due to the inertia of their moving parts and consequent “lag”. In each class instances are given of instruments which are free from the error, but the Robinson cup anemometer—in which the authors are more particularly interested—is not one of those. As nothing was known definitely as to the effects of lag in this case, an investigation was undertaken, using a specially designed apparatus analogous to the cup anemometer, and, for greater accuracy of measurement, currents of water instead of air.

A description of this apparatus is given; and the remainder of the paper is occupied with the mathematical theory and the results of experiment. The most striking of these is the fact that the instrumental error is always positive; that is to say, that when the current fluctuates the instrument registers too great a flow.

The authors desire to record their thanks to Professor MacGregor for the facilities he has provided, and for the kind interest he has taken in their work.

Part of the special apparatus described was obtained by a grant from the Tait Memorial Fund.

The mercury vapour lamp, although very economical in its use of electrical energy, is not employed very extensively at the present day for illuminating purposes, chiefly because the light it emits is not white, but of a greenish hue. Many attempts have been made to produce the deficient red radiation, but these have so far not met with any great success. The lamp, however, is useful as an illuminant where the colour of the light is of no great importance, such as in public works, etc. Further, it is very much used, in the form of rectifiers, for changing alternating to direct electrical current. During the past few years there has been an increasing demand for lamps which are rich in ultra-violet radiation, which is useful for photographic and medical purposes, as, for example, the sterilisation of water, milk, etc. This requirement is met by the mercury vapour lamp, for the ultra-violet spectrum of mercury is particularly intense; lamps used for this purpose must be made of quartz, since ordinary glass absorbs ultra-violet radiation. Then, again, the mercury spectrum is extremely useful in spectroscopic work as a reference spectrum.

In a paper communicated to the Royal Society of Edinburgh, Mr Manley describes a differential densimeter and its successful application in the laboratory to the rapid determination of the relative densities of sea-waters. The paper also contains the suggestion that the instrument would, if suspended in gimbals, be rendered available and convenient for use at sea: thus making it possible for the oceanographer to carry out observations upon the density of sea-water with greater frequency than the usual methods conveniently permit.

The absorption spectra of the copper, nickel, and cobalt salts investigated in this series do not seem to depend so much upon the acid radical as on the water of solution. The latter evidently plays a very important role, and possibly complicates matters. It was therefore resolved to determine the molecular extinction coefficients in alcohol and in acetone to see whether conditions were any simpler there. It may be stated in advance that they are not.

This article describes work done with the spectrophotometer with the view of clearing up four different points arising out of the earlier articles. At the time it was commenced, the hope of finding a mathematical connection between absorption spectra and molecular structure had been given up, at least so far as aqueous solutions were concerned, and attention was being concentrated on some chemical questions arising out of the work. The spectrophotometer and methods were the same as had been used in Nos. II., III., VI., VII., and VIII. of the series.

In this paper a short account will be given of the present state of the theory of the absorption of light, with special reference to the results gained in this series of investigations.

Theories of the dispersion of light may be divided into two classes: (1) those in which the body is regarded as consisting of particles which vibrate under the influence of the light wave; and (2) those in which the body is regarded as consisting of obstacles which diffract the light wave. According to (2), light is scattered, not absorbed; a wave going through the body diminishes in intensity, but the energy lost is radiated out laterally without change of wave-length.

Writers on mammalian anatomy are united in stating that one of the characteristics of the Cetacean family Physeteridæ is the presence of functional teeth in the lower jaw only. Typical statements are those of Flower and Lydekker (1891): “No functional teeth in the upper jaw”; Beddard (1900): “Teeth found in both jaws, but those of lower jaw alone functional; often very reduced in number”; Turner (1912): “Functional teeth in lower, but not in upper jaw.” A possible exception is the Pigmy Whale, Kogia, in which the upper jaw may altogether lack teeth or may possess an anterior rudimentary pair (as in K. simus, Owen) the utility of which is a matter of some doubt.

The rôle played by the “free” (negative) electrons in metallic conductors as carriers of the electric current has formed the basis of theories developed by H. A. Lorentz, Sir J. J. Thomson, E. Riecke, and others, regarding the thermo-electromotive force. In these theories the free electrons are considered collectively as an ideal gas permeating the metal and subject to the usual gas laws. The kinetic theory of gases is then applied to the problem of the motion of the atoms of the electronic “gas,” and expressions for the thermo-E.M.F.—differing in the various instances by a constant multiplier only—are deduced.

It has been shown in a former paper that an equation of the form

can be applied to give close representation of results in the determination of the law of decrease of torsional oscillations of wires of different materials, when the range of oscillation is large in comparison with the palpable limits of elasticity.

This paper is a continuation of one already submitted to the Society, and published in their Proceedings.

It showed that an equation of the form yn(x + a) = b could be applied to give close representation of results in the determination of the law of decrease of torsional oscillations of wires of different materials. This empirical equation, in which y represented the range of oscillation, x the number of oscillations since the commencement of observations, and n, a, and b constants for any one experiment, their numerical values depending upon the initial conditions of the wire and its subsequent treatment, was found to hold over a large range of oscillation for wires of many metals, and the present paper gives an account of further work on the subject.

The electrograms (continuous records of the atmospheric potential) were obtained by means of electrographs of the Kelvin water-dropper type at the Physical Laboratory, Edinburgh University, and the Royal Observatory, Blackford Hill, and as the inspection of the records showed some remarkable similarities, a more detailed comparison of the records was instituted, the results of which are given in this paper.

In 1903 I communicated to the Society a paper on the relation between magnetization and resistance of nickel at high temperatures (1). In this paper the magnetization was along the direction in which the resistance was measured. A second paper, in which the magnetization was transverse to the direction in which the resistance was measured, was communicated in 1906 (2). In these later experiments a flat coil of nickel wire was used; and it was necessary to use very high fields before an appreciable change of resistance was obtained.