the earth's axis, the retrogradation of the moon's nodes, the equilibrium of Saturn's rings, and the peculiar effect of a magnet upon an iron disc in rotation. He had been led to the construction of the first of these instruments so long ago as 1835, from the difficulty he experienced while teaching astronomy, in explaining the subject of precession by mere verbal description. He conceived that the motions of the common spinning-top might be converted into an exact imitation of those of the earth, by altering the position of the centre of gravity in reference to the point of support. In the conception of such an instrument, he was not aware at the time that he had been anticipated by others; but he now found that the records of the Royal Astronomical Society contained a short and obscure notice of a similar instrument, which had previously been constructed by Mr. Atkinson. M. Bohnenberger's gyroscope had also been previously known on the Continent, and partially in this country, which, among other purposes, exhibited correctly the precession of the equinoxes; and Mr. Higginson, now present, had, it appeared, constructed an instrument of the same kind. The effect of a magnet on a rotating iron disc had been shewn to him (Professor Elliot) by a friend, but almost accidentally, and without reference to its theory or astromical application. Its use for that purpose was to exhibit the effect of one planet in disturbing the plane of another planet's orbit, in eight different positions of the disturbing body (as described in Newton's Principia), in producing a forward or a backward movement of the nodes, or an increase or diminution of the obliquity of the plane of its orbit to the ecliptic. Professor Ellibt stated that, although his experiment with the iron ring and magnet was admitted to be an exact imitation of the peculiar motion of Saturn's rings, yet the coincidence of the two in regard to principle had been disputed

by some of our best mathematicians. The objection advanced to it by Professor Thomson, of Glasgow, that the one was, to a certain extent, a constrained, and the other a perfectly free motion, was certainly a valid objection; but there were some difficulties attending the subject which required to be removed by further experiment. He (Professor Elliot) had shown the greater part of these experiments to the Liverpool Polytechnic Society in the year 1839. Since that time the subject of rotatory motion had become a fashionable study among mathematicians, having been taken up successively by Professors Magnus, Wheatsone, Powell, Foucault, Smyth, and Maxwell. Foucault's experiment for shewing the stability (perfect or partial) of a rotating disc during the earth's rotation was not new in theory, as it had been described more than twenty years before by Mr. Sang; nor was it in his (Professor Elliot's) opinion practically successful in shewing the earth's rotation, since its success depended altogether upon the adjustment of the apparatus, and the only mode, he believed, of making that very delicate adjustment, was by trying if it produced the very motion it was intended to demonstrate. It could be made to shew the rotation of the earth, or not to shew it, just as it was balanced. Professor Smyth's apparatus he had previously described. Professor Maxwell, of Aberdeen, was the last who had produced any thing new on the subject of rotatory motion, and in a set of beautiful experiments, and some refined calculations, he had advanced further into the subject than any of his predecessors. Professor Maxwell's principal object was to throw light on the theory of Saturn's ring. In his essay, for which he lately had the high honour of gaining the Adams' Prize offered by St. John's College, Cambridge for the best dissertation on that subject, Professor Maxwell objected to the applicability of his

Professor Elliot's) experiment on the iron ring to that of Saturn, but agreed with him in maintaining that Laplace's hypothesis of a load on the ring was untenable. Professor Elliot briefly described two other experiments which he had himself made in regard to rotation. One of these consisted in magnetizing the axis of a light rotating disc, carefully depriving the disc of all precessional movement, inclining its axis a little from the vertical line, placing over its centre an electro-magnet, and then giving to the disc a rapid rotation on its axis. The axis remained at rest in its oblique position till an electric current was passed along the wire of the electromagnet; as soon as that was done the axis of the disc began to revolve round the magnet. When the current was transmitted in the opposite direction, the direction of revolution immediately changed, producing a singularly close resemblance to that mysterious phenomenon, electro-magnetic rotation. The other experiment consisted in taking a very large cylindrical vessel of water, making a small orifice in the centre of the base, with a straight brass pipe extending a few inches downward, the outer end of the pipe being closed with a plug, and the inner end being made perfectly smooth. The vessel was filled with water, and as soon as that had attained perfect repose the plug was withdrawn. This being done, as the level of the water sank, it gradually acquired a rotatory movement, at first very slow, but becoming more rapid as the evacuation proceeded, and always in the direction of the earth's rotation, provided that perfect stillness of the fluid had been secured. The rationale of the process was this: That the vessel of water participated in the earth's diurnal rotation; its own motions consisting of a revolution round the earth's axis and a slow rotation on its own axis, that the portions near the circumference had a more rapid motion in rota

tion than those near the centre. In approaching the centre they retained their actual velocity, and consequently increased in angular velocity, and, in escaping at the central orifice, produced a vortex in the direction of the earth's rotation, affording another experimental proof that such rotation existed.

FIFTH ORDINARY MEETING.

ROYAL INSTITUTION, 14th December, 1857.

The REV. H. H. HIGGINS, M.A., V.P., in the Chair.

ROBERT TOPHAM STEELE, Esq. was elected an Ordinary Member.

The resignation of Mr. C. Millward was accepted.

The death of Mr. S. T. Winstanley was communicated. Mr. A. HIGGINSON submitted portions of the skeleton of a shark, and explained its anatomy.

Mr. T. C. ARCHER exhibited a series of English lichens, prepared by Dr. W. L. Lindsay, together with fabrics dyed by them.

Mr. WHITEHEAD exhibited portions of the wooden keel of a vessel extensively destroyed by the teredo navalis, also specimens of the worm.

The paper of the evening was then read "ON THE SMELTING AND ASSAYING OF TIN ORES, &c.," by NEWTON SAMUELSON, Esq., F.C.S.

SIXTH ORDINARY MEETING.

ROYAL INSTITUTION, 11th January, 1858.

The REV. H. H. HIGGINS, M.A., V.P., in the Chair.

CHARLES BOTTERILL, Esq., was elected an Ordinary Member.

A paper was read "ON THE PRESERVATION OF FRESH MEATS, &C., IN METALLIC CASES," by CHRISTOPHER BELL, Esq.

The author entered into the details of the various processes in use, the particulars of which he had ascertained, and illustrated the same by specimens of home and foreign product. In presence of the members, many cases were opened, some of which had been sealed. for ten and fourteen years. Mr. Goldner's stood this severe test, as well as those prepared by the Messrs. McCall and Co., his successors in the business. one of the canisters opened was unsound, but the home was better than the foreign. The The process of preservation was the coagulation of the albumen and expulsion of oxygen, effected by simple means effectually applied. The following paper was then read:

Not

NOTES ON SOME OF THE PRINCIPAL STATIONS FOR BOTANIZING

IN THE NEIGHBOURHOOD OF LIVERPOOL.

BY THE REV. H. H. HIGGINS, M.A., SEN. V.P.

THE vicinity of Liverpool has for many years been diligently examined by botanists in search of phanerogamic plants, and their labours have been rewarded by the discovery of a series probably as extensive as any collected in Britain within a district of similar extent.