of England and France, to express temperature in future in none but centigrade degrees, would quickly become general, and form an universal language in this respect, to the expulsion of Fahrenheit's ridiculous scale, as well as the others, which occasion such unnecessary delay and difficulty in fixing the different degrees of heat in the memory, when running through chemical experiments in both the languages.

I may also perhaps be permitted to mention, to those who are making experiments on the conversion of starch into sugar, by Kirchoff's method, that if the boiling be performed by passing steam into the fluid, all risk of empyreuma may be avoided, desiccation prevented, (as the volume will continue any length of time nearly the same,) and the operation can be performed in porcelain, earthen ware, or even wood vessels.

Mr. Wilkinson, the celebrated Iron-master, could not produce any current of air through cast-iron pipes, (extending about a mile in length,) even to the distance of 600 feet from the impelling force, which was very great; yet the gas-light companies find no difficulty in this respect.-May I request an explanation of this anomaly from any of your correspondents?

XII. Formation of Sal-Ammoniac in burning Bricks.

(To Dr. Thomson.)

I. H.

SIR, In your Sketch of the latest Improvements in the Physical Sciences, under the division Salts, article Sal-ammoniac, you observe," that the sand employed in making bricks probably contains common salt, derived from the sea water with which it is washed; and that this may be the source of the muriatic acid, which goes to the formation of the sal-ammoniac that sublimes during the burning of the bricks; but that if this be the case, nature employs, during this process, some method of decomposing common salt, at present unknown to manufacturers, &c."

In reply to this observation, I beg leave to remark, that as sulphate of ammonia generally accompanies the volatile products of burning coals, it is not improbable that this salt decomposes the common salt that adheres to the sand, and gives rise to the production of the muriate of ammonia in question.

I shall be much obliged to you to inform me, of some practicable method of separating manganese when in solution from the solution of a neutral salt. A minute portion of this metal communicates a permanent stain to a considerable quantity of any neutral sulphate that may happen to contain it.

Bristol, Jan. 14, 1815.

I remain, Sir, your most humble servant,

E. T. I.

ARTICLE XV.

List of Patents.

ROBERT SALMON, Woburn, Bedfordshire; for improvements in the construction of machines for making hay. Aug. 22, 1814. JOHN DICKINSON and GEORGE LONGMAN, Nash Mills, Hert fordshire; for improvements in the said John Dickinson's patent machinery for manufacturing paper, and also a certain apparatus for separating the knots or lumps from paper or paper stuff. Aug. 24, 1814.

JAMES PENNY, of Low Nibthwaite, Lancaster, mechanic; and JOSEPH KENDAL, same county, turner; for a new and improved principle of making pill and other small boxes. Sept. 8, 1814.

WILLIAM LISTER, Paddington, Middlesex, Esq.; for certain further improvements on an engine for separating corn or seeds from the straw and chaff. Sept. 21, 1814.

JAMES DOBBS, Birmingham, Gentleman; for his improvements in the manufacturing of machines used for cutting and gathering in grain and produce arising from the earth, whereby much labour and expense are saved. Sept. 21, 1814.

JOSEPH TAYLOR and PETER TAYLOR, Manchester, machinemakers; for having invented and brought to perfection certain improvements in a loom to be used in weaving cotton, linen, worsted, silk, or other cloth or clothes, made of any two or more of the said materials. Sept. 21, 1814.

W. E. SHEFFIELD, Somer's Town, Middlesex, Gentleman; for divers improvements in the working or manufacturing of copper and its compounds, and other metallic substances, or any or either of the same. Sept. 21, 1814.

W. SAMPSON, Acorn-street, London, millwright; for certain improvements for raising water. Oct. 3, 1814.

ABRAHAM SHAW, Leicester, glazier's vice and diamond manufacturer; for his apparatus for the better cutting of window, plate, and sheet glass. Oct. 3, 1814.

AMBROISE FIRMIN DIDOT, Holborn, London, Gentleman; for an improvement in the method of making types or characters to be used in the art of printing. Oct. 3, 1814.

R. PHILIPS, Newbury, Bucks, engineer; for certain improvements in a plough. Oct. 5, 1814.

JAMES LONGHURST; for an Eolian organ or barrel organ with a self-acting swell. Nov. 1, 1814.

JOHN WALTERS, Fenchurch-strect, London; for certain improvements in the construction and fastening of frame timber or binds of ships or vessels, whether building or under repair. Nov. 7, 1814.

WILLIAM HOWARD, Old Brentford, Middlesex; for improved apparatus for working the pumps on board ships, which may also be applied to churning, and various other useful purposes. Nov. 10,

1814.

1814. Wind. Max. Min. Med. Max. Min. Med. Evap. Rain.

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.

Twelfth Month.-4, 5, 6. Slight hoar frosts in the ponds: windy at intervals. 7. Occasional small rain. 8. The max, temp. of the last 24 hours this morning, with a hollow S. W. wind. An unsteady rain followed, of many hours' continuance, with much wind at S. 9. Windy: the barometer appears to have stood through the night at the min. noted. 10. Hoar frost: Cirrostratus: overcast, a. m. : after one, the day wet and stormy: much wind in the night. 11. Cloudy: rain before nine, and at intervals through the day. Though it was very cloudy, the bees came out in great numbers, as observed about the same time last year. 12. Temp. this morning 54°, with low driving clouds, and a gale at S. W. 13. Early this morning the wind was violent: it moderated about three p. m. : and the clouds, after a squall, assumed the Cumulostratus. Much water out in the marshes. 14. Red sun-rise: Cirri over the sky, with their extremities drawn out westward: p. m. it blew hard again from S. W. followed by rain at night. 15. a. m. Much wind and cloud. The millers, who have remarked that for two years past our atmosphere has been calmer than usual, will now probably complain of an excess of wind. The Cumulostratus appeared after three p. m. and the evening and night were calm. 16. Early this morning the wind rose again, and blew with great violence, with rain at intervals, till about three p. m., when the same change ensued as yesterday. 17. Overcast: windy: some rain p. m. : a gale through the night, 18. The tempestuous weather continues. 19. A shower about eight a. m., and again in the evening, after which light clouds were observed to pass the moon's disk with less and less velocity. 20. Hoar frost: a fine and nearly calm day: swarms of gnats in the air, and gossamer floating. The dew froze on the grass by half past four p.m. there was a corona round the moon, and a Stratus, at night. 21. Hoar frost. 22. Dry air; steady breeze: Cirrus, passing to Cirrostratus. A lunar halo of large diameter. 23, 24. Cloudy: steady breeze. 25. Some snow in the night, followed by a little more in the day. 26. a. m. Snow more plentiful: a thaw. 27. Rain: sleet and snow: rain again, 28. The max. temp. early this morning: much rain. 29. Overcast sky. 30. Misty. 31. Hoar frost: large Cirrus clouds: a few drops of rain: p. m. Nimbus.

First Month, 1815.-1. Hoar frost: a rose-coloured sky, with Cirrostratus at

sun-set.

RESULTS.

Winds in the fore part Westerly and violent; in the latter, Easterly and moderate: but in both attendant with rain: but one clear day in the period.

ANNALS

OF

PHILOSOPHY.

MARCH, 1815.

ARTICLE I.

A Biographical Account of David Rittenhouse,* LL. D. F. R. S. late President of the American Philosophical Society.

By Thomas Thomson, M.D. F.R.S.

THE Rittenhouse family from which our philosopher was descended emigrated from the province of Guelderland to New York, towards the end of the 17th century, when that state was in the possession of the Dutch. They soon removed to Germantown, in Pennsylvania, where they established the first paper-mill ever erected in America. Matthias, the youngest son of Nicholas Rittenhouse, our philosopher's grandfather, was born at Germantown, about eight miles from Philadelphia, in 1703. Having abandoned the occupation of a paper-maker when about 29 years of age, and two years after his' father's death, he settled at Norriton, a farm which he had purchased of about 150 acres, and situated about 20 miles from Philadelphia. In the year 1727 he had married Elizabeth Williams, the daughter of Evan Williams, a native of Wales. This woman had been left an orphan, and was brought up by an old Gentleman in the neighbourhood called Richard Jones. She possessed a cheerful temper, and a mind uncommonly vigorous and comprehensive.†

The veneration in which this Gentleman was held in America, and the very high opinion entertained of his genius and scientific attainments, induce me to suppose that a short account of him will be acceptable to my readers. My information is derived from a biographical account of him published in Philadelphia in 1813, by his nephew, Mr. William Barton. I perused this book with much pleasure. The views which it gives of politics, philosophy, and religion, are excellent, and such as I scarcely expected from an American philosopher of the present day.

+ Mr. Barton conceives that the abilities of David Rittenhouse were derived VOL. V. No III. Ꮮ