Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 3, 1802).djvu/48

iRd IRO for making cast metal or pig iron from the ore, and manufa6turing it into bar, or any other malleable iron, deserve particuLir notice. — The reader will iind these, together with the various patents relative to the iron manufailory, miniltely de- scribed in the different volumes of the Repertory of Arts and Manu- Jaciures. Beside its utility as a material for implements of agriculture, Src. iron is eminently adapted to the purpose of dyeing cotton. From the various experiments made by Chap- TAL, it appear.s that tiie o.^yd of iron has so great an affinity for cot- ton thread, that if the latter be im- mersed in a saturated solution of this metal in any acid, it assumes instantaneously a chamoy-yel'.ow colour, which becomes more or less deep, according to the strength of the liquors, and the length of time it has been exposed to the air. The colour thus communicated is fixed j resists both air and water, and also alkaline leys ; nor is its durability in the least affefted by washing it "with soap i which, on the contrary, imparts to it additional brightness. The oxyd of iron, if precipitated on any stuff, easily unites v/ilh the fawn colour obtained from vege- table astringents ; and, by varying the strength of the soda, soap, or other mordants employed in dye- ing, an inhnity of si:adea may be produced. Thus, by means of a boiling heat, the oxyd of iron may be mor6 intimately combined with the astringent principle. These colours may likewise be rendered brown, as they are susceptible of a variety of shades, from a bright grey to a deep black tint ; by simply passing the cotton impregnated with astringent vegetable matter, through a solutipn of iron. When long exposed to {[. .' , Iron is ver)"- Hable to become r^ y, especially in moist situations : hei)cc an effei^ual method of preserving it bright, still remains to be disco- vered. Various compositions have indeed been contrived for this pur- pose ; but none appears to be more: serviceable than common oil, though its use is on man}' occasions both troublesome and disagreeable. To obviate these incouveniencies, it has been recommended to heat the irou to such a degree, that it cannot bd touched without burning the hand, then to vnrnish it witii new white wax, and expose it to the lire, till the wax is completely imbibed by the metal, which should next be rubbed over with a piece of serge. — According to others, this metal may be perfectly secured from the effefts of rust, by plunging itj while red-hot, into linseed-oil^ wiiich is suffered to drop off till it become dry, and then wiping the iron ith a clean cloth. Thus a black crust or varnish is formed, which renders it impervious to moisture. Again, others jwur melt- ed lead into the oil, before it is ap- plied to the heated iron ; but both preparations require a considerable degree of skill and precaution. Iron, when imported in British ships from the United States of America, is exempt from duty y but if it be brought in American vessels, it is liable to a duty of 5s. 7'd. per ton, and 10s. lOd. per ton for convoy-duty. — I'he sura ot 10s. 10-Ki. is paid on iron, whe- ther in rods, or drawn, or ham- mered le.-s than three-fourths of an inch square, if imported from lUissia in British ships ; but, if in foreign bottoms, it is subjeiS: to' the duty of lis. 3|d. per cwt. In medicine^ irou is cliiefly em- plovetl