348

COTTON DYEING.

to fishermen’s nets, and in the construction of life-boats. Its impermeability to water hasled to its employment for inner soles to shoes.

When cork is rasped into powder, and subjected to chemical solvents, such as alcohol,&c., it leaves 70 per cent, of an insoluble substance, called suberine. When it is treatedwith nitric acid, it yields the following remarkable products:— White fibrous matter0-18, resin 14-72, oxalic acid 16-00, suberic acid (peculiar acid of cork) 14-4 in 100parts.

Machine cork-cutting. — A patent was obtained some years ago by Sarah Thomson forthis purpose. The cutting of the cork into slips is effected by fixing it upon the slidingbed of an engine, and bringing it, by a progressive motion, under the action of a circularknife, by which it is cut into slips of equal widths. The nature or construction of amachine to be used for this purpose may be easily conceived, as it possesses no new me-chanical feature, except in its application to cutting cork. The motion communicatedto the knife by hand, steam, horse, or other power, moves at the same time the bed also,which carries the cork to be cut.

The second part of the invention, viz., that for separating the cork into square pieces,after it has been cut into slips as above, is effected by a moving bed as before, upon whichthe slips are to be placed and submitted to the action of a cutting lever, wiiich may beregulated to chop the cork into pieces of any given length.

The third part of the invention, viz., that for rounding or finishing the corks, consistsof an engine to which is attached a circular knife that turns vertically, and a carriage orframe upon its side that revolves upon an axle horizontally.

This carriage or frame contains several pairs of clamps, intended respectively to holda piece of the square cut cork by pressing it at the ends, and carrying it lengthways per-pendicularly ; which clamps are contrived to have a spindle motion, by means of a pinionat the lower end of their axles, working into a spur-wheel.

The machinery, thus arranged, is put in motion by means of bands and drum-wheels,or any other contrivance which may be found most eligible; and at the same time thatthe circular knife revolves vertically, the frame containing the clamps wilh the pieces ofcork, turns horizontally, bringing the corks, one by one, up to the edge of the knife, when,to render each piece of cork cylindrical, the clamps, as above described, revolve upon theiraxes, independently of their carriage, by which means the whole circumference of thecork is brought under the action of the knife, the superfluous parts are uniformly paredoff, and the cork is finished smooth and cylindrical.

CORROSIVE SUBLIMATE; bichloride of mercury.

CORUNDUM ; or Telesie ; a very hard genus of aluminous minerals, to which thegems, sapphire, ruby, salamstein, and adamantine spar belong.

COTTON DYEING. (Teinture de Coton, Fr.; Baumwollenfarberei, Germ )Cotton and linen yarns and cloths have nearly the same affinity for dyes, andmay therefore with propriety be treated, in this respect, together. After they haveacquired the proper degree of whiteness (see Bleaching), they are still unfit toreceive and retain the dyes in a permanent manner. It is necessary, before dipp‘ n Sthem into the dye-bath, to give them a tendency to condense the coloring particleswithin their cavities or pores, and to communicate such chemical properties' as willfix these particles so that they will not separate, to whatever ordinary trial they maybe subjected. All the colors which it would be desirable to transfer to these stuffs unfor-tunately do not possess this permanence. Men of science engaged in this important art haveconstantly aimed at the discovery of some new processes which may transfer into the classof fast colors those dyes which are at present more or less fugitive. Almost all thegoods manufactured of cotton, flax, or hemp, are intended to be washed, and ought)therefore, to be so dyed as to resist the alkaline and soapy solutions commonly used it*the laundry. Vitalis distinguished dyed cottons into three classes; 1. the fugitive , ° rfancy-colored ( petit teint), which change their hue or are destroyed by one or twoboils with soap; 2. those which resist five or six careful washings with soap, are good dy e ’-*(bon teint ) ; and those which were still more durable, such as Turkey reds, may becallefast colors (grand teinl). The colors of Brazil-wood, logwood, annotto, safflower, & c ->are fugitive; those made with madder without an oily base, are good; and those °^ mader with an oily mordant, are fast. It is, however, possible to point out certain processfor giving these different orders of dyes a greater degree of fixity.

I shall describe, in the five following paragraphs, the operations conducive to theation of colors upon cotton and linen. ' . j

1. Galling. Either gall-nuts alone, or sumach alone, or these two substances un * ’are employed to give to cotton the fast dye preparation. 2 or 3 ounces of galls for e tpound of cotton, being coarsely pounded, are to be put into a copper containing a30 gallons of water for every 100 pounds of cotton, and the bath is to be boiled tilll the s

of galls feel pasty between the fingers. The fire being withdrawn, when the bathbeeomoderately cool, it is passed through a hair-cloth sieve. If during this operation