صور الصفحة
PDF
النشر الإلكتروني

rents, mixed with ten per cent of fixed air. Two measures of this hydrogen gas, after the carbonic acid had been separated from it, and one of oxygen gas, left near a measure of inflammable air, mixed with fifty per cent of fixed air.

A fire was kindled at half past eleven o'clock, by placing a quantity of the Lehigh coal, upon a stratum of common charcoal in a powerful air furnace, which was then filled with equal. portions of the two fubftances.

As faft as the charcoal confumed, the Northampton coal was added, and at half paft one, the furnace was completely filled with it, and two-thirds of it red hot. At four the coal was half confumed, and it continued burning until eleven o'clock at night.

Five of Wedgwood's thermometer pieces, put in crucibles made of porcelain, were depofited in different places among the coal, that they might defcend in different directions, and fome of them be expofed to the greatest degree of heat.

When they were cool, being measured by the gauge, they gave 70, 77, 150, 156, and 159, degrees.

125 is the highest heat Mr. Wedgwoood could ever produce, in a common fmith's forge, and 160 in an air furnace, eight inches fquare. Brafs melts at twenty-one, copper at twenty-feven, filver at twenty-eight, gold at thirty-two, and caft iron at one hundred and thirty of this thermometer. The welding heat of iron is one hundred and twenty-five.*

James's river coal, fubmitted to an experiment of the fame kind, burned out in four hours.

A fire was made with the Lehigh coal, in a smith's forge, and two thick bars of iron were placed in it, and welded with great eafe, by the proprietor of the furnace.

The fmith, his journeymen, and bystanders were convinced, that the heat was much cleaner and greater, than that of the James's river coal.

* Description and use of a thermometer for measuring the higher degrees of heat, by Jofiah Wedgwood. Phil. Tranf. Vol. 72d.

As the Virginia coal burns with flame and much smoke, a vaft portion of this combustible substance, and the heat generated by it, is loft by paffing up the chimney.

It appears from fome of thefe experiments, that this coal does not unite to the base of oxygen gas, with as much rapidity as common charcoal, and that it decompofes water. Its flame confifting of oxyde of carbon, or carbonated hydrogen gas, arifes from this decompofition.

When it is exposed to a red heat, and contains little water, it gives rife to a peculiar fpecies of inflammable air, without any fixed air ; but when the fteam of water is tranfmitted over it, in a red heat, the production of carbonic acid gas is very confiderable, and when the hydrogen gas, thus obtained, is fired with oxygen gas, the fixed air generated amounts to thirty-five per cent more than when it is procured from coal united to a small .quantity of water.

According to the opinions, now generally adopted by the Philofophers of Europe, the gafes, when little water is mixed with the coal, muft confift of oxyde of carbon and carbonated hydrogen gas. It will be faid, the oxgyen of the water, unites to part of the coal and forms oxyde of carbon, while its hydrogen escapes, dissolves a portion of the coal, and makes carbonated hydrogen gas.

This explanation is far from being fatisfactory; for no oxyde of carbon can be detected in the gafes, produced by extinguishthis coal when red hot under water, or by fubmitting it to heat in an earthen retort.

The Lehigh coal promises to be particularly useful, where a long continued heat is neceffary, as in diftilling, or in evaporating large quantities of water from various substances; in the melting of metals, or in fubliming of falts; in generating steam to work steam engines; and in common life, for washing, cooking, &c. provided the fire-places are conftructed in fuch a manner, as to keep up a strong draught of air.

MEDICAL AND PHILOSOPHICAL

REGISTER.

A

FOREIGN AND DOMESTIC..

Ta stated meeting of the American Philofophical Society, held at Philadelphia, for promoting useful knowledge, on the 19th of April, 1805.

William Tilghman, Efq. was duly elected a member of the fociety.

THE thanks of the fociety are prefented to the following perfons for their Communications and Donations.

COMMUNICATIONS.

On the Italian manner of managing Silk-worms. By R. K. Lowry, received through the President of the Society.

On the Manufacture of Cloth from the Fur of Seal-skins, accompanied with fpecimens. By R. R. Livingston.

DONATIONS FOR THE CABINET.

Sundry fpecimens of minerals, chiefly from Elba. By John D. Clifford.

Specimens of lead ore and its gangue, found on Perkioming creek. By James Meafe, M. D.

Rock crystal on ferruginous ftone, from Washington City. By J. B. Smith, Efq.

Engravings of the heads of Dr. Rush, Dr. Wistar, and Dr. Barton, from Mr. Haines the engraver.

Engraving (framed) of Richard Price, D. D. By Thomas C. James, M. D.

A Chinese mariner's compafs. By D. Davis.

DONATIONS FOR THE LIBRARY.

Medical Thefes, felected by C. Caldwell, M. D. 8vo. 1805. By T. & W. Bradford.

Jacob Chriftian Schaffer's Semtliche Papier Verfuche, containing 84 fpecimens of paper, chiefly made from vegetables, with obfervations on the mode of manufacturing them. By William Hamilton, Efq.

Plan de Paris à vol d'oiseau, gravé en 20 planches, par ordre des Echevens de la Ville, fol. 1739.

Travels in Egypt and Nubia. By F. L. Norden, 2 vols. in 1, fol. Lond. 1757. Thefe two by P. S. Du Ponceau, Efq. Bill of Mortality for Portsmouth, 1804. By L. Spalding. Facts and Arguments in favour of Inland Navigation in the United States. By Camach, Efq.

Genuine Principles of Navigation. By Mr. George Baron, of New York, 1803. By the Author.

Reports of Directors of the Chesapeake and Delaware Canal. by J. Gilpin.

Memoirs of the Life and Correfpondence of Sir William Jones. By Lord Teignmouth. Philadelphia, 1805. By Mr. William Poyntell.

Effai fur les Propriétés Médicales des Plantes, comparées avec leur formes extérieures & leur claffification naturelle. By A. P. Decandotte.

Mathematics compiled from the beft Authors, for the Ufe of Harvard College. By the Compiler, Samuel Webber, A. M. Eulogy by Profeffor Webber, on the Rev. Jofeph Willard. By the Corporation of Harvard College.

Conditions of the Magellanic Premium.

M. JOHN Hyacinth De Magellan, in London, having some time ago offered as a donation, to the American Philofophical Society held at Philadelphia for promoting useful knowledge, the sum of two hundred guineas, to be by them vested in a secure and permanent fund, to the end that the interest arising therefrom should be annually disposed of in premiums, to be adjudged by the society, to the author of the best discovery, or most useful invention, relating to navigation, aftronomy, or natural philosophy (mere natural history only excepted) and the society having accepted of the above donation, hereby publish the conditions, prescribed by the donor, and agreed to by the society, upon which the faid annual premiums will be awarded.

1. The candidate shall fend his discovery, invention, or improvement, addreffed to the President, or one of the Vice Presidents of the fociety, free of postage or other charges; and shall distinguish his performance by some motto device or other signature, at his pleasure. Together with his discovery, invention, or improvement, he shall also send a sealed letter, containing the fame motto device or fignature, and subscribed with the real name, and place of residence of the author.

2. Perfons of any nation, fect, or denomination whatever, fhall be admitted as candidates for this premium.

3. No discovery, invention, or improvement, shall be entitled to this premium, which hath been already published, or for which the author hath been publicly rewarded elsewhere.

4. The candidate fhall communicate his discovery, invention, or improvement, either in the English, French, German, or Latin language.

5. All fuch communications shall be publicly read, or exhibited to the fociety, at some stated meeting, not less than one month previous to the day of adjudication; and shall at all times be open to the inspection of such members as fhall defire it. But no member shall carry home with him the communication, description, or model, except the officer to whom it shall be intrusted; nor shall fuch officer part with the fame out of his cuftody, without a special order of the fociety for that purpose.

6. The fociety having previously referred the several communications, from candidates for the premium then depending, to the confideration of the twelve counsellors and other officers of the fociety, and having received their report thereon, shall, at one of their stated meetings in the month of December, annually, after the expiration of this current year, (of the time and place, together with the particular occafion of which meeting, due notice shall be previously given, by public advertisement) proceed to the final adjudication of the said premium: and after due confideration had, a vote shall first be taken on this queftion, viz. Whether any of the communications then under inspection be wor

« السابقةمتابعة »