The method of experiment by which the following results have been obtained has been described in the abstract of Part I., published in the “Proceedings” February 1877. All the experiments were performed on dogs.

During the months of May and June of this session, we have endeavoured to investigate certain questions suggested by our experience of the discharge of electricity through the gases and through oil of turpentine.

Ordinary paraffin-oil, when used as a dielectric, exhibits the same phenomena as oil of turpentine. Gas is liberated by the passage of the spark, and at the same time carbon is deposited. Once produced, the gas bubbles make the passage of the spark more easy through bringing the electrified surfaces nearer to one another; hence, in taking a series of observations, it is necessary to get rid of the bubbles after the passage of each spark. They were attracted generally to the positive surface, but sometimes to the negative. The attraction was more marked when no jars were attached to the Holtz; it was not so powerful as in oil of turpentine, and was generally in the opposite direction.

At a recent meeting of the Society, Dr Crum Brown exhibited a gutta percha bottle of irregular form, which, when applied as a resonance cavity to reeds of various pitches, gave very good imitations of certain vowel sounds. By closing certain apertures in the side of the bottle it could be made to say A (“father”), A (“awe”), O (“oh”), and I (“machine”). When the cavity was kept constant, and the pitch of the reed was altered, the same vowel continued to be given. Dr Crum Brown was good enough to lend us the apparatus, in order that we might investigate the sounds given by the bottle in the same way as we have been investigating certain human vowel sounds, by obtaining and magnifying phonographic traces, and then subjecting them to harmonic analysis as far as the sixth partial tone.

It is widely known that a destructive epidemic has this spring appeared among the salmon of the rivers Eden, Esk, and Nith. The mortality among the fish has been so great as to cause considerable alarm among proprietors, salmon commissioners, taxmen, anglers, and the general public.

The newspapers inform us that within three days the watchers have taken out of the Esk as many as 350 dead salmon. All who have examined the fish carefully, agree in referring the disease to the presence of a fungoid growth.

It is generally stated that isomorphous salts are capable of crystallizing together in any proportions, or that the isomorphous elements which enter into them are capable of replacing one another in any proportion; e.g., potash alumina alum and potash iron alum can crystallise together in all proportions.

The method for the separation of these two groups hitherto in use was first proposed by Berzelius, and has been followed by almost all chemists who have investigated these earths. For the details of this method we must refer to his “Handbuch;” but we may briefly state that it depends on the relative solubilities of the double sulphates of these metals with potassium in a saturated solution of potassic sulphate.

Recent discussions as to the nature of vowel-sounds have led us to make experiments (partly with an apparatus constructed some years ago for the same purpose) upon the effect of a periodic variation of intensity of a simple tone.

It is obviously impossible to secure a simple harmonic variation, so we endeavoured to produce a displacement varying as

1 − cos mt.

An organ-pipe, giving a tone very free from harmonics, was sounded on one side of a partition in which were cut a series of large holes.

Two years ago I had an opportunity of making from the deck of the steamer “Pharos” some observations on the performance of the fog-siren at Sanda, off the Mull of Cantire, The instrument is worked by air at about 1¼ atmospheres pressure; and, though driven by a powerful air-engine, sounds for 7 seconds only per minute. One obvious defect of such an arrangement I saw to be the waste of energy in producing a current of air through the trumpet of the siren along with the oscillations.