14. Rare Minerals found in the Vicinity of Edinburgh. Within these few months beautiful specimens of deeplycoloured prehnite have been found in Salisbury Craigs. In several of these, the prehnite was associated with that kind of datolite described under the name Humboldite by Mr. Levy. In the basaltic rock of the Castle Hill, small but beautiful specimens of radiated Wollastonite have been found. Many years ago, fine specimens were got. The same mineral occurs occasionally in greenstone of Salisbury Craigs.-(Edin. Phil. Journ.)

15. Discovery of Selenium in the Volcanic Rocks of Lipari.

Dr. Turner has just sent to us the following interesting notice, the substance of which was communicated to him by Prof. Stromeyer. "Prof. Stromeyer has lately discovered selenium under two different forms, one of which is altogether new. On diluting some fuming sulphuric acid, such as is made at Nordhausen from the sulphate of iron, he observed that a solid matter separated from the diluted acid, which, on examination, proved to be selenium. One pound of the acid gave on dilution about a grain of selenium. This substance has already been detected in some of the Bohemian sulphuric acid; and it is supposed that the acid in question had been prepared in Bohemia. The second source of selenium is in the volcanic productions of the Lipari Isles, among which Prof. Stromeyer has lately discovered a native sulphuret of selenium. He has mentioned neither the mineralogical character of the new mineral, nor given an account of his chemical examination of it; but I hope soon to obtain from the Professor more full information on the subject; and shall then have great pleasure in communicating it to you. It appears probable from these circumstances, that selenium is a more common production of nature than is generally supposed; and it may be anticipated that it will frequently be found, whenever the attention of chemists and mineralogists in general shall be directed to the subject."-(Edin. Phil. Jour.)

MISCELLANEOUS.

16. Light and Heat from terrestrial Sources.

Mr. B. Powell, FRS. has, during the last winter, been engaged in a series of experiments on the light and heat emitted from incandescent and burning bodies, in extension of those of MM. Leslie, de la Roche, &c. The principal question investigated is one with regard to the nature of the heating agents, which very naturally arises from the results of the experiments just alluded to: viz. whether, of the effect from a luminous hot body, the part intercepted by a glass screen is of the same nature as, or different from, the part transmitted, (independently of the heat acquired and radiated again by the screen). The result of

various experiments conducted upon different principles was, that the two are essentially distinct. The part of the effect intercepted by glass being shown to have a greater relation to the texture of the surface on which it acts, and the part transmitted to the darkness of colour.

17. Explosive Engine..

An engine of a very remarkable kind is, we understand, about. to be brought into public notice, which, if it answer the high expectation of its inventor, may ultimately supersede the use of the steam-engine. The patents for England and Scotland are, we believe, both completed, so that we may expect soon to hear the particular details of its construction.

At the lower end of a small cylinder is placed a minute apparatus for producing oil gas. As the gas is generated, it elevates a piston so as to admit as much atmospheric air as, when combined with the oil gas, would render the mixture explosive. When the piston has reached this height the gas is exploded, and the mechanical force of the explosion is employed to drive machinery. Experiments have, we understand, been actually made with this power, which was employed to force up water to a considerable height.

Our readers will no doubt be reminded by this brief notice, of the ingenious invention of the Rev. Mr. Cecil, by which the power is obtained by taking advantage of the vacuum created by the explosion of a mixture of hydrogen and common air.-(Cambridge Transactions, vol. i. part 2.) Mr. Cecil suggested in his paper that the expansive force of the explosion might also be employed; but his machine was not founded on this principle. (Edin. Jour. of Science.)

18. Electricity produced by Congelation of Water.

When water is frozen rapidly in a leyden jar, the outside coating not being insulated, the jar receives a feeble electrical charge, the inside being positive, the outside negative. If this ice be rapidly thawed, an inverse result is obtained, the interior becomes negative, and the outside positive. Grothus.-(Jour. of Science.)

ARTICLE XIX.

NEW SCIENTIFIC BOOKS.

PREPARING FOR PUBLICATION.

The History of Mollusca, containing a Description of all the Species of Recent and Fossil Shells. By J. E. Gray, MGS. This work will be published in Parts, each forming a complete work, illustrated with figures of all the new species, and furnished with Indices, and a geological list of the fossils.

JUST PUBLISHED.

Meteorological Essays and Observations. By J. Frederick Daniell, FRS. With Plates. 8vo. 16s.

Elements of Phrenology. By George Combe, President of the Phrenological Society. With Plates. 4s.

A Descriptive History of the Steam-Engine. By Robert Stuart, Esq. Civil Engineer. Illustrated by Engravings of 47 Steam-Engines.

8vo. 8s.

Phillips's Flora Historica. 2 vols. 24s.

Parkes's Chemical Catechism. Enlarged Edition. 14s.

Bland's Hydrostatics. 1 vol. 12s.

A General Index to the first 19 vols. of the Edinburgh Medical Journal. 8vo. 16s.

ARTICLE XX.

NEW PATENTS.

J. Wells, Manchester, silk and cotton manufacturer, for his machine for dressing, stiffening, and drying cotton and linen warps, or any other warps that may require it, at the same time the loom is working.-May 25.

J. Holland, Fence House, Aston, York, shoemaker, for certain improvements in the manufacture of boots and shoes.-May 31.

J. Heathcoat, Tiverton, Devon, lace manufacturer, for improvements in the methods of preparing and manufacturing silk for weaving and other purposes.-June 15.

W. A. Jurup, Middlewich, Chester, salt proprietor, and W. Court, Esq. Manor Hall, Chester, for their improved method of manufacturing salt.-June 15.

R. Hooton, of the Aqueduct Iron Works, Birmingham, for certain improvements in manufacturing wrought iron.-June 15.

W. Harwood Horrocks, Stockport, Chester, cotton manufacturer, for his new apparatus, giving tension to the warp in looms.-June 15.

R. Garbutt, of the town of Kingston upon Hull, merchant, for his apparatus for the more convenient filing of papers and other articles, and protecting the same from dust or damage, including improvements on the files in common use.-June 15.

W. Harrington, Esq. Crosshaven, Cork, for his improved raft for transporting timber.-June 15.

C. Chubb, Portsea, Southampton, ironmonger, for his improvements in the construction of locks-June 15.

B. A. Day, Birmingham, Warwick, fire-screen maker, for certain improvements in the manufacturing of drawer, door, and lock knobs, and knobs of every description.-June 15.

J. M'Curdy, Snow-hill, for an improvement in the method of generating steam.-June 15.

P. Taylor, City-road, engineer, for certain improvements in apparatus for producing gas from various substances. June 15.

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.

6.

Sixth Month.-1, 2. Fine. 3. Overcast.

4. Fine and overcast. 5. Fine.

Fine: a Stratus on the marshes at night. 7. Fine: sultry. 8. Sultry. 9. Fine. 10. Rainy day. 11, 12. Fine. 13. Rainy night. 14. Showery. 15. Cloudy.

21, 22. Fina. 23. Very

16. Fine: rainy night. 17, 18. Fine. 19, 20. Rainy. rainy. 24. Rainy. 25. Cloudy. 26. Cloudy. 27. Fine. 28. Cloudy. 29, 30. Fine.

RESULTS.

Winds: N, 6; NE, 7; E, 2; SE, 3; S, 5; SW, 3; W, 1; NW, 2; Var. 1.