ed continually, and rarely with fufficient intervals to refresh myself by rest. I am fincerely, Sir, your most obedient, October 25th, 1804. SAMUEL K. JENNINGS. To the Editor of the Philadelphia Medical Museum. Obfervations on the Mode of Refining Camphor. By JAMES WOODHOUSE, M. D. Profeffor of Chemistry in the University of Pennsylvania, &c. SIR, I' November 26th, 1804. T must afford fincere pleasure to every true friend of America, to view the establishment and rapid increase, of several branches of manufactures, in the United States. Too long have our citizens been dependent upon other nations, for many articles, to purify or fabricate which, requires but a small capital, and a very flight degree of chemical knowledge. Among the fubjects which we may confider as coming under this head, is the obtaining of refined camphor, from the raw material. Crude camphor is imported by our merchants from Canton and Batavia, where it is bought for fifty and feventy-five cents, and fells in this country, from a dollar, to a dollar and eleven cents a pound. Eight years fince, the refining of this article, was confined to two druggifts in the United States, and at this time there are not more than eight perfons, who accurately understand the process, all of whom keep it a profound fecret. The method was for a long time, known only to the Dutch, who value and conceal all discoveries, in proportion as they are connected with the art of making money. It is not taught in any of the elementary works of Fourcroy, Chaptal, Lagrange, Gren, Nicholson or Thomson, nor in any of the Medical Difpenfatories. A tolerably accurate account of the procefs, may be feen in the French Encyclopædia, and in the twelfth volume of Ars & Metiers, by De Machy. The apparatus neceffary for a refinery is fimple, does not coft much, and occupies little room. It confifts of a furnace, fupporting a fand-bath, glass vessels, and iron, copper or earthen pans. I. OF THE CONSTRUCTION OF THE FURNACE. A furnace fufficiently large for one active and industrious man to attend, will occupy the space of eight feet nine inches in length, and two feet fix inches in breadth. It must be made of feven caft-iron plates, half an inch thick, thirty inches long and fifteen broad. These plates are to be placed upon eight piles of bricks, parallel to each other, and nine inches apart. The bricks are to be ten inches high, thirty long, and fix broad. Great care must be taken, that the lower fides of the plates meet each other exactly midway on the upper fide of the bricks, which fhould be well covered, with a thick bed of mortar. Bricks ferve to confine the fand. When the furnace is connected with a wall, there is no occafion for more than a fingle row of them: and to obtain a confiderable draught of air a chimney should be carried from the fourth plate, with an aperture four inches in diameter, and the flues of the third and fifth plate, may communicate with this chimney. Two separate flues, may be carried from the second and fixth plates, and the first and seventh fhould enter the fecond and fixth. The chimney, if convenient, may be made to enter into that of the house, but if not, it should be about fifteen feet high. II. OF THE GLASS VESSELS. The veffels are procured at a glass-house, and are made of green glafs. They should be blown as thin as an oil flask. They are of a circular form, fhaped flat like a turnip, and have a neck from one to three inches high, with an aperture, from half an inch to one inch in diameter. Their bottoms should be eleven inches broad, and the top ought to be four inches from the bottom. They coft twenty-five dollars a hundred in Philadelphia. |