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motion to be wholly produced by the centre of gravity of the piece of camphor, and of the fluid displaced by it not being in the same vertical line. If that were so, an irregular piece of any substance capable of floating on water should, under the same circumstances, exhibit the same phenomena as a piece of camphor, which is not the case. Another, and cooperating cause must, therefore, be looked for; and there seems no reason to doubt that it is correctly assigned in M. Biot's abstract. Yours, F. B.

9. Improvement in Clocks.

The public papers, sometime since, contained information of an improvement in timekeepers, invented by Mr. Dyer, of this city. We hope hereafter to furnish our readers with a more particular account of this invention than is contained in the following brief notice :

The most important feature in this improvement consists in the application of the spiral teeth to the wheel-work of clocks, and in this the pinion is reduced to a single tooth. By this happy idea, Mr. Dyer has greatly reduced the wheel-work necessary to a clock, and the friction is diminished in a still greater degree; as all who are acquainted with the spiral gearing are aware that the point of contact, between two wheels with spiral-teeth, always coincides with the line of centres. Mr. Dyer has also contrived a very ingenious method of suspending the pendulum, in place of the spring, or knife-edge suspension. This method is to hang the mass constituting the pendulum to a plane, the under surface of which rolls at every oscillation upon a fixed convex body. He proposes to give such a curve to the convex surface, that the pendulum, in vibrating, shall be accelerated at every moment of its descent by a force proportional to the arch between it and the lowest point; this condition being required to render the vibrations isochronal. Mr. Dyer has not yet demonstrated the curve necessary to obtain this result; but from the constant variation of the centre of oscillation, in a pendulum suspended in the above method, the cycloid is not the curve required. He is aware that his suspension cannot be executed with such accuracy as to render the vibrations perfectly isochronal; but he may undoubtedly obtain a near approximation to a curve which would render them so.-(Boston Journ. of Philosophy and the Arts, May, 1824.)

10. Method of cleaning Gold Trinkets, and of preserving engraved Copper-plates.

The method used by artists for cleaning gold trinkets is the application of a mixture of neutral salt, intended to disengage nitric acid, with the assistance of heat. Dr. Mac Culloch recommends instead to boil the trinkets in water of ammonia,

which dissolves the metallic copper of the alloy to a certain depth on the surface, so that after the operation the metal is in fact gilded, nothing but pure gold being visible. In this process the waste of gold, which is dissolved by the acid, in the process usually employed, is avoided.

Dr. Mac Culloch observes, "that it is an unaccountable omission of chemists not to have observed that metallic copper is soluble in ammonia. The solution takes place rapidly in the heat at which the water of ammonia boils."

Copper-plates are apt to be injured by laying by; a thin coat of oxide forms on the surface, which is rubbed off by the hand of the workman in the first inking, when the plate is again called into use; and by repetition of the formation of oxide, and its removal, the fine lines on the plate are soon injured, and ultimately obliterated. Dr. Mac Culloch recommends the application of common spirit varnish to the surface when the plate is laid by; it is easily applied, and can be removed when requisite by spirit of wine.-(Edinburgh Journal of Science.)

ARTICLE XV.

NEW SCIENTIFIC BOOKS.

PREPARING FOR PUBLICATION.

The Fourth Volume of the New Series of the Memoirs of the Manchester Literary and Philosophical Society.

A Compendium of Medical Theory and Practice, founded on Dr. Cullen's Nosology, which will be given as a Text Book. By D. Uwins, MD. in a duodecimo volume.

Muscologia Britannica: containing the Mosses of Great Britain and Ireland. By W. J. Hooker, FRS. ASL. &c. and T. Taylor, MD. MRIA. FLS. &c. 8vo. With Plates.

Mr. Swainson will speedily publish in an octavo volume, with six Plates of the most beautiful humming Birds of Mexico, the "Zoology of Mexico," illustrated by general Remarks and scientific Descriptions of the Animals collected by Mr. Bullock; to whose Travels the work is intended as an Appendix.

JUST PUBLISHED.

Wade's Observations on Fever. 8vo. 4s.

Woodford's Catalogue of Phænogamic Plants in Edinburgh. 12mo. 3s. 6d.

Harrison's Surgical Anatomy of the Arteries. Vol. I. 12mo. 5s. Sandwith's Introduction to Anatomy and Physiology. 12mo. 9s. The Butterfly-Collector's Vade-Mecum. 12mo. 5s.

Stevenson's Historical Sketch of the Progress of Discovery, Navigation, and Commerce, from the earliest Records to the beginning of the 19th Century. 8vo. 14s.

Otter's Life and Remains of the Rev. E. D. Clarke. 4to. 31. 3s. The Encyclopædia Metropolitana, Part XII. containing, among other subjects, the completion of the article on Magnetism, Electromagnetism, and Electricity; and from CAP to CHI in the Miscellaneous Division.

ARTICLE XVI.

NEW PATENTS.

J. Crosby, Cottage-lane, City-road, for his improvement in the construction of lamps or lanterns, for the better protection of the light against the effects of wind or motion.-May 5.

J. Viney, Shanklin, Isle of Wight, for improvements in water-closets. -May 6.

W. Cleland, Leadenhall-street, for his improvement in the process of manufacturing sugar from cane juice, and in refining of sugar and other substances.-May 6.

J. T. Paul, Charing Cross, mechanist, for improvements in the methods of generating steam, and in the application of it to various useful purposes.-May 13.

J. Potter, Smedley, Lancashire, spinner and manufacturer, for certain improvements in looms.-May 13.

J. Perkins, Fleet-street, engineer, for his improved method of throwing shells and other projectiles.-May 15.

W. Church, Birmingham, for improvements in the apparatus used in casting iron and other metals.-May 15.

J. H. Ibbetson, Smith-street, Chelsea, for improvements in the manufacture of gas.-May 15.

L. W. Wright, Wellclose-square, engineer, for improvements in machinery for making pins.-May 15.

J. Luckcock, Round Cottage, Edgebaston, near Birmingham, for his improvement in the process of manufacturing iron.-May 15. W. H. James, Cobourg-Place, Winson-green, near Birmingham, engineer, for his improved method of constructing steam-carriages.May 15.

T. Parkin, Bache's-row, City-road, merchant, for improvements in machinery for printing.-May 15.

J. Dickinson, Nash Mill, Hertford, for his method of cutting cards by machinery, and also a process for applying paste or other adhesive matter to paper by means of machinery.-May 20.

J. Cook, Birmingham, gun-maker, for improvements in the method of making and constructing locks for guns, pistols, and other firearms.-May 20.

T. Marsh, Charlotte-street, Portland-place, saddler and harnessmaker, for an improvement in the making of saddles.-May 20.

J. Viney, Shanklin, Isle of Wight, for his method of supplying water or fluids for domestic or other purposes in a manner more extensively and economically than has hitherto been usually practised.-May 22. B. Black, South Molton-street, Hanover-square, lamp manufacturer, for his improvement on carriage-lamps.—May 25.

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The observations in each line of the table apply to a period of twenty-four hours, beginning at 9 A. M. on the day indicated in the first column. A dash denotes that the result is included in the next following observation.

REMARKS.

Fifth Month.-1. Fine. 2, 3. Rainy. 4, 5. Showery. 6-8. Fine. 9. Fine: a solar halo, coloured, a little before sunset. 10. Fine: a lunar halo of the largest diameter. 11. Overcast: cold wind: a lunar halo at night, with a bright spot on each side, at the same height as the moon. 12. Showers. 13. Rainy. 14. Rainy. 15. Rain, without ceasing, all day. 16. Cloudy. In consequence of the heavy rains of the last four days, amounting on the whole to 2.91 inches, a flood was naturally expected this morning; and towards evening the waters rose suddenly in the sea, and passing over all the banks of the level, soon filled the marshes, and in the course of the night rose to an unprecedented height, being 24 inches higher than in the flood of 1809. The houses in the marshes south of the road were filled nearly to the chamber floors, and some of the inmates removed with great difficulty: the flood remained stationary for nearly 24 hours. On the 17th in the afternoon, it began very gradually to subside, and on the 18th, in the morning, was much abated; the marshes still presenting the appearance of a bed, the tops of the trees appearing in places only. 17-19. Cloudy and fine. 20-23. Fine. 24. Morning showery. 25-29. Fine. 30, Fine: a slight shower in the morning. 31, Cloudy and fine.

RESULTS.

Winds: N, 6; NE, 8; E, 3; SE, 1; SW, 5; NW, 8.

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