BYE

DYE

( 381 )

*otton with a ley of impure foda in large claypans with a very narrow neck, and fet in brickover a fire place. The boiling continues fortwenty-four hours.

A dye-houl'e for giving to cotton yarn a finefed equal to the Turkey red was eftablifhed atGlafgow by Mr. Papillon, the fecret of whichWas purchaled by the Commiffioners for Manu-factures in Scotland , and has been made publicnot long fince. “ It confifts of a very clofeimitation of the Adrianople procefs, as alreadydefcrxbed, but with a confiderable faving in thelength and number of applications. The par-ticulars need not be here enumerated, but itmay be mentioned generally that it confiits ofthe diftinct operations of boiling with foda,

■—deeping in a compound bath of (beep's dung,oil, foda and other ingredients—oiling withoutthe dung—galling—-aluming—dyeing with mad-der and blood—fixing the colour with the dungand oil fteeps—and lallly brightening the dyewith a finilli of foap-water and foda.

Mr. Kauffman in his obfervations upon Adri-anople procefies, announces a great Amplificationin the number of procefies and an alteration inthe mordants, by which he aflerts that a redmay be procured fully equal to that of theLevant. 0 The mordant which he propofes is acompound folution of alumine and oil in cauftiealkali, and is made in the readieft way by addingcauftic alkali to a hot concentrated folution ofalum, which firft precipitates, then rediffolvesthe alumine, after which a fmall portion of lin-feed oil (and probably fifh oil would anfwer fullas well if not better) is to be put in, and thewhole mixed into a cream-like liquor. Cottonfteeped twice (or where fine colours are wanted,thrice) in this alumino-oily foap appears to bethen fit for maddering and to retain the colourin great perfection.

To give a full dead-red like that of the India handkerchiefs, Berthollet directs that the cottonfhould firft be boiled in lime-water; then fteepedin the bath of foda, oil, and gaftric liquor ofIheep or other ruminating animals; wafhed;fteeped in a mordant of acetite of alumine (madeby alum and fugar of lead) and laftly maddered.In this cafe the finifhing procefs is not required.The colour thus produced is a full red withoutluftre, and the deadnefs of colour appears to beowing to the lime-water.

Cotton dyed red may be brought downthrough all the intermediate ftiades to a paleorange, by fteeping for a longer or Ihorter timeill. nitrat of tin. As a general rule, to give the

* Phil. Mag. voi-1?.

brighter colours the cotton rauft be but mo-derately oiled and galled, fteeped for a length oftime and often in alkaline leys of the weakerfort, largely alumed, dyed with the beft andbrighteft madder, and at the laft long and plen-tifully foaped.

Such in a general way are the procefies bywhich the red colour of madder may be madedurable on cotton and linen. The ftiades ofdegraded red producible by adding any ironfolution to the aluminous mordant are endlefs.It may only be added that for the fake ofeconomy the fame bath may often be ufed withadvantage, both for the fme bright reds and forthe violets, wine colour, and other darker (hades,by employing for the former the madder bathwhen firft warm and frefh, and for the latterthe fame bath when fully boiled, where the dunyellow part of the madder begins to prevail, andin which it can produce no material injury tothe intended colour.

Of Cochineal Scarlet and Red.-

Whoever cafts his eyes on a piece of broad-cloth dyed in the mod perfect manner with thefine or cochineal fcarlet, muft be ftruck withits tranfcendant beauty and luftre, and acknow-ledge it to be one of the fineft efforts of the artof dyeing.

The fcarlet dyeing in general makes a diftindtbranch of trade, the materials being of thatdelicate kind as eafily to be hurt by accidentaladmixture of other colours, and part of theapparatus being fomewhat different from thatof common dyeing. The boiler in which thecochineal bath is made is generally of tin orftrongly tinned copper, for as a folution of tinis the mordant employed, no harm can arifefrom its being in contact with the fame metal,but copper might be fomewhat acted on in theprocefs and the dye injured. The quality ofthe water is alfo of importance here, whichfhould be foft and pure, for hard water tendsto produce a rofe colour, which however is cor-rected by boiling bran or ftarch in it.

Cochineal (the peculiar nature of which isdefcribed under that article) contains a vaftquantity of colouring matter in proportion toits weight, and yields it very readily to watercold or hot. The infufion of cochineal is natu-rally of a fine crimfon, and is entirely an adjec-tive colour, but with a mordant- it fixes onwoollen and filk with great firmnefs, but weaklyand with difficulty on linen and cotton.

Alum appears to have been the mordant firftemployed to fix the colour of cochineal on wool..

• An. Chim. tom. 41*