During the past two months my attention has been directed to the telephone, chiefly as an instrument which illustrates in a remarkable way the delicacy of hearing. As some of these experiments are novel, and may possibly assist those who are investigating the physical phenomena of the instrument, I beg to give a short account of them to the Society. To save circumlocution in description, the term “proximal” will be applied to the telephone receiving the stimulus, and the term “distal” to the one at the other end of the arrangement. Thus, if A talks to B, A will use the proximal, and B the distal telephone.

Last summer session, with the assistance of Messrs Salvesen, Connor, and Stewart, I applied the method of measuring great differences of potential, described in a paper by Mr Paton and myself (Proc. Feb. 19, 1877), to investigate the laws of passage of the electric spark. The method essentially consists in connecting the prime conductor of the Holtz machine, not with the electrometer directly, but with an insulated spherical ball. This ball acts inductively upon another insulated spherical ball which is in connection with the electrometer.

The authors describe the preparation, properties, and action of heat upon the following compounds of trimethyl-sulphine:—

1st, The sulphide [(CH3)3S]2S;

2d, The hyposulphite (thiosulphate) [(CH3)3S]2S2O2, H2O;

3d, The oxalate [(CH3)3S]2C2O4, H2O.

In answer to your question about the alteration of surface in quartz crystals, I place the glass or quartz plate whose refractive index χ is to be determined between two right-angled flint-glass prisms, with oil of cassia, and measure the angle θ, at which total reflection begins from the hypothenuse of the first flint-glass prism; the angle θ can easily be calculated from i, μ the refractive index of the flint-glass, and P the angle of the prism. Sunlight falls from a collimator with a slit upon the system of flint-glass prisms, and after passing through the second prism is examined by a direct vision set of prisms, I turn the system of flint-glass prisms until the spectrum appears to be broken off at a definite Fraunhofer line, measure the angle i, and thus obtain—

Professor Jenkin called attention to experiments made by Mr Gott in St Pierre, and published in the Journal of the Society of Telegraph Engineers. Mr Gott converted two siphon recorders into a telephonic system by mechanically connecting the suspended coils with diaphragms. In this experiment the only conceivable mode of action was analogous to that suggested by Professor Graham Bell as the explanation of his telephone. This explanation, if not complete, was not, in Professor Jenkin's opinion, erroneous. Professor Jenkin announced that he had, with Mr J. A. Ewing's assistance, constructed one of Mr Edison's phonographs, and that this instrument, like the telephone, gave a nasal intonation to the words spoken by it.

In this paper it is not proposed to discuss in their relations to storms the effects of rain, of the earth's rotation, of areas of high and low pressure external to the storm-area, and of the prevailing westerly winds, which are doubtless occasional factors in the progressive movement of storms. What it is intended to show here is that storms possess in themselves a self-motive power, by which their onward movement over the earth's surface is determined.

Professor Fleeming Jenkin and Mr J. A. Ewing exhibited a phonograph which they had constructed, and also some curves drawn on paper representing the indentions produced in the tinfoil of the instrument by vowel sounds.

The phonograph exhibited had been constructed from a description of the instrument invented by Mr Edison, and consisted of a barrel about four inches diameter and four inches long, mounted on a spindle on which a square-threaded screw had been cut. One bearing of the spindle was cylindrical, and the other was a nut in which the screw worked. A fly-wheel handle turned the spindle and barrel, which advanced during each turn by a distance equal to the pitch of the screw. A helical groove, about in. in breadth, was cut on the surface of the barrel, having the same axial pitch as the screw on the spindle.

This paper contains the results of a laborious series of experiments and calculations carried out during the last ten years, the object being the repetition and extension to other metals than iron of Forbes' experiments, described to the Society in 1862 and 1865.

In this paper the authors gave a preliminary account of experiments made with the help of the phonograph exhibited at the last meeting. The following results have been obtained:—

1. The vowel sounds can be produced by maintaining the relative pitch of the simple tones of which they are composed constant, although the absolute pitch of those simple tones may vary greatly.

Before giving the action of ethylene on the chlorides of iodine. I may shortly describe the method of preparing the latter, which I found to be the most advantageous:—

A weighed quantity of perfectly dry iodine being introduced into bulb A of flask 1, perfectly dry chlorine gas is passed over it, A being at the same time heated over a water-bath to about 60° to 80° C. The ICl3, as it is formed, volatilises and condenses almost entirely in B, only a small portion escaping into flask 2. Chlorine is passed until no more iodine remains in bulb A. If the heating be omitted, only the outermost layers of iodine are converted into the trichloride, a kernel remaining unacted on. (Compare Christomanos, Berl. Ber. X. No. 5, p. 434.)

The integrals referred to occur in connection with applications of the Method of Electric Images. A curious special case was given to the Society in July 1875, but was not inserted in the “Proceedings.” It depended on the fact that the image of a sphere, whose surface density is inversely as the cube of the distance from a point, is another sphere with a similar law of distribution. But any desired number of integrals, whose values can be at once assigned, may be obtained by various applications of the following process.

A couple of months ago I had the honour of submitting to the Society a speculation upon the metamorphism of a particular rock mass. To-night I again return to metamorphism, submitting, however, not a speculation, but the closely elaborated process of the change which has affected another rock.

In a historical introduction the author gives an outline of the progress of research into the history of the Old Red Sandstone of the British area. This system is at present regarded as composed of three sub-divisions, Lower, Middle, and Upper, each characterised by a distinct suite of organic remains. From the absence of unequivocally marine fossils, and from lithological characters, it has been inferred by Mr Godwin Austin, Professor Ramsay, Professor Rupert Jones, as well as other observers, and is now very generally admitted, that the Old Red Sandstone, as distinguished from the “Devonian” rocks, probably originated in inland sheets of water.

According to a usage which has been adopted from the German of Helmholtz by the best English scientific writers on sound, a sound is called a “simple tone,” or without qualification a “tone,” when the variation of pressure of the air in the neighbourhood of the ear which is the immediate excitant of the sense is according to a simple harmonic function of the time; that is to say, when the whole pressure of the air varies in simple proportion to the distance, from a fixed plane, of a point moving uniformly in a circle.