A series of reflex adjustments of balance disturbed round the anteroposterior and horizontal axes are described in the domestic duck.

THE minor fluctuations of the atmospheric pressure are now engaging the close attention of meteorologists, and my own attention has been drawn to them on account of their connection with the oscillations of lake-surfaces generally known since Forel's investigations under the name of seiches.

As these fluctuations often do not exceed a millimetre or two of water, they are not shown by the ordinary self-registering apparatus. In order to record them we may use a specially sensitive form of barograph, such as the Richard statoscope, which is delicate enough to show these small fluctuations, and yet can be brought back to a momentary zero whenever the indicator threatens to go off the scale or beyond the limits of safety. There are, however, two objections to this method of measurement.

In taking cranial capacity as a ground of comparison between the Anthropoids and Man, he gave some measurements of skulls contained in the Museum. The capacity of the cranial cavity in the Gorilla skeleton belonging to the Museum is 29 cubic inches. Considerably larger gorilla skulls, however, have been measured. The smallest healthy adult human skulls in the Museum are those of two Andaman Islanders. Of these, one has a cranial capacity of 75·5 cubic inches, and the other a capacity of 72 cubic inches. Next to these comes a Peruvian skull; its cranial cavity measures 76 cubic inches. The smallest healthy adult human skull measured by Morton was also that of a Peruvian, whose cranial capacity measured only 58 cubic inches.

The following facts appear to have been conclusively established by universal experience:—

1. Nearly all, if not all, solid substances become self-luminous at the same temperature.

2. The red rays are the first to become visible, and, on increasing the temperature, colours of less wave-lengths are successively added in the order of their wave-lengths.

3. While colours of shorter wave-lengths are being added, those which were previously visible become more intense.

The extinction of the Tasmanian aboriginal in 1876 closed, for all practical purposes, the further scientific study of this ancient and highly interesting race, and it appeared almost certain that our knowledge of this people would remain dependent on the earlier works of those who were fortunate enough to have studied them during life, and on the few remains housed in such fortunate centres as London, Paris, Edinburgh, Oxford, and Cambridge.

This is a direct continuation of an earlier communication by the author, on “The Revised Prepared System of the Quadratic Complex,” which appeared in vol. lvi (1936) of the Society's Proceedings, pp. 38–49. It will be convenient to utilize the same notation and references to earlier works I, II and III as before, with IV to denote the 1936 paper. A complete system of concomitants for a quadratic complex is here worked out; omitting polar forms, it consists of 210 forms. The sign ≡ in a relation A ≡ B is here used to mean “may be replaced by”: thus A is equal to a non-zero numerical multiple of B plus reducible terms.

The first obvious difficulty which presents itself, in trying to derive Clerk-Maxwell's equations from those of the elastic-solid theory, appears in the fact that the latter, being linear, do not impose any relations among simultaneous disturbances. Thus, for instance, they indicate no reason for the associated disturbances which, in Maxwell's theory, constitute a ray of polarised light. Hence it appears that we must look on the vectors of electric and magnetic force, if they are to be accounted for on ordinary dynamical principles, as being necessary concomitants, qualities, or characteristics of one and the same vector-disturbance of the ether, and not themselves primarily disturbances. From this point of view the disturbance, in itself, does not correspond to light, and may perhaps not affect any of our senses. And the very form of the elastic equation at once suggests any number of sets of two concomitants of the desired nature, which are found to be related to one another in the way required by Maxwell's equations.

Lakes whose causal conditions are due to the direct interposition of glaciers, may be formed in one or other of the two following ways. First, when a glacier descending a lateral valley protrudes so far as to dam up a river in the main valley, the obstructing element being either the actual ice or the morainic débris deposited from it. Or, secondly, when a glacier occupying a main valley blocks up the outlet of some tributary stream. In both instances the water accumulates behind the obstruction and so forms a lake, varying in size according to the height of the barrier and the surface configuration of the district immediately above it.

The problem in question is to determine the equation of the curve traced out by any point of an elliptic or hyperbolic disc which touches two fixed rectangular axes. Mechanically constructed figures of different forms of the curve have been given by Tait, who also showed that the same glissette can be traced either by means of an ellipse or a hyperbola. If p, q are the coordinates of the tracing point referred to the axes of the disc as axes of coordinates, the glissette is clearly the θ eliminant of

and Cayley stated that it would be found to be of order 8 in x, y. The actual elimination was first performed by Muir, who obtained in the first instance an equation of order 10. On dividing by an extraneous quadratic factor a lengthy equation of order 8 was obtained; and subsequently Lord M'Laren verified the accuracy of the terms of highest order in this equation.

Two earthquake shocks have lately occurred in Argyleshire of so decided a character that a description of their effects, as observed at four of the Lighthouse stations on the west coast of Scotland, will, it is thought, be interesting to the Society.

The first shock occurred on the 11th March, and was observed at the Lighthouse station of Hynish in the island of Tyree, and at Sound of Mull, near Tobermory, the distance between the two places being about 34 statute miles.

The periodic variations of the temperature of water have been studied for some months at the Scottish Marine Station at Granton. The only tidal basin which has been considered as yet is the haven formed by the irruption of the sea into Granton Quarry. It has an area of about 7 acres; the tidal entrance is on the west side, and is so situated that no water can enter until about half tide; then it comes in as a very rapid stream for about three-quarters of an hour, when the rate falls off, and near high water it is the same as that of the rising tide on the shore. The ebb is gradual until the tide has narrowed the channel by uncovering the sandbanks which lie on each side of the entrance, then it is rapid for about an hour and a half, after which the water runs out ext'remely slowly, and does not absolutely cease until the tide begins to re-enter; but for from four to five hours the water-level inside is practically unaltered. The depth of the quarry at low water varies from 5 to 8 fathoms in the parts where observations were made, and at high water the depth is slightly more than 1 fathom greater. The bottom shelves off abruptly from the bar at the entrance.

This paper contains the substance of investigations made for the most part many years ago, but recalled to me during last summer by a question started by Sir W. Thomson, connected with Laplace's theory of the tides.

A comparison is instituted between the results of various processes employed to reduce the general linear differential equation of the second order to a non-linear equation of the first order. The relation between these equations seems to be most easily shown by the following obvious process, which I lit upon while seeking to integrate the reduced equation by finding how the arbitrary constant ought to be involved in its integral.

Whether the variation of resistance in conductors in a steady magnetic field depends on the field strength, on the magnetisation, or on both, does not seem to be definitely settled. The various experimental methods as yet used are fundamentally similar in principle, and have the disadvantage that the experiments are difficult to perform.

A method where the experimental difficulties are very few is to be found in the comparison of the variation of resistance for any given field-strength with some other phenomenon whose dependence on the field-strength or on the magnetisation is already known, and whose exact determination offers no experimental difficulties.

FAM. EUPHROSYNIDÆ.—In Euphrosyne foliosa, Aud. and Ed., the separate nerve-cords are comparatively large, and lie quite within the body-wall, the oblique muscles, which generally bound the longitudinal ventral muscles, decussating beneath them.

AMPHINOMIDÆ.—The cords are somewhat small and flattened in Chloeia, and occupy an area bounded internally by a transverse band of fibres, and externally by the circular muscular layer and the hypodermic basement-tissue. The oblique muscles are attached at the outer border of each trunk.

In but a few cases are solutions of equations of the type

known, and even in the simplest cases the most general of the known solutions suffers from the disadvantage of being in a symbolic form. The equations to be studied in the present paper are those which can be derived from

by a change in the independent variable. This equation is the one which most naturally claims the attention of the investigator, after the equation of wave-motion

has been disposed of.

The effect of the friction of the crushing plates upon the yield point of short compression specimens has been investigated.

With plates harder than the material under test, the end friction causes an increase in the apparent yield point. This increase is calculated as 18 per cent. for wrought iron and mild steel, 20 per cent. for cast iron, and 50 to 200 per cent. for stones, bricks, and concrete. These figures, except the first, may apply almost equally well to the crushing strength, but they require experimental support. The corresponding inclinations of the surfaces of shearing are 37° for wrought iron and steel, 36° for cast iron, and 27° to 15° for stones, etc. The first value is seldom obtained, but the others agree fairly well with average experimental results.

When the crushing plates are of material softer than that under test, the lateral flow of the former diminishes the apparent strength of the specimen. With stones crushed between lead plates the strength is calculated as 0·35 to 0·15 of that obtained when iron or steel plates are employed. Experiments give 0·65 to 0·43 as the value of this ratio, but the specimens do not rupture by shearing in the manner contemplated.

The total crushing load of a short specimen of cast iron is increased by diminishing the length of the piece, but the crushing stress per unit of area is simultaneously decreased.

The ages of the various tribes and sub-tribes of Compositæ have been calculated in doubling periods, according to Yule's formulæ; these are known briefly as Dp-ages (Small and Johnston, 1937; Udny Yule, 1924). Yule advises caution in interpreting Dp-ages in terms of geological time, but if his conceptions are to be applied to realities there should be some method of comparing Dp-ages with actual ages. Further, in the case of Compositæ, an almost complete parallel seriation has been found for Dp-ages and order of origin of both tribes and sub-tribes (Small and Johnston, 1937). Since the order of origin has been provisionally correlated with geological time (Small, 1919) it is possible to compare the calculated Dp-ages with suggested points of origin in geological time. This has been done by Small and Johnston (1937, Tables, VI, VII).

It became evident during the War that some men who are organically sound are nevertheless incapable of supporting heavy exertion; and among the older groups that were called to the Colours in 1918 the proportion of such individuals was considerably more. The effect of forcing these men to carry out the duties falling to the lot of an “A” recruit was in many cases harmful to them, and in extreme instances resulted in permanent disability and sometimes in death. The Army Medical Department therefore sought to obtain a method of physical examination, which would supplement the ordinary medical examination of a recruit, and which could be applied to men who proved to be unserviceable material in the hands of the drill sergeant—a test which would, in fact, enable the malingerers to be distinguished from those who were truly incapable of sustained labour.

When an iron wire is magnetised longitudinally, it lengthens in the direction of magnetisation, according to an old discovery of Joule's. More recently Wiedemann showed that when wire is at the same time magnetised circularly it tends to twist. Thus, if an iron wire be fixed at one end, and stretched vertically by means of a mass attached to the free end, the free end will twist round when the wire is both traversed by one current and magnetised by another which traverses a helix surrounding it. If the wire is magnetised so as to have the north pole down, a down current will make the free end twist in the direction of the hands of a watch as looked at from above. Eeversal of either current reverses the direction of twist; reversal of both produces no alteration. Maxwell and Chrystal have pointed out that Wiedemann's phenomenon can be explained by means of Joule's.