Page:Encyclopædia Britannica, first edition - Volume I, A-B.pdf/678

 570 B L E A < : H I N G. foap is apt to leave a yellownefs in the cloth. It is vitriol-fours do it in as many hours ; nay, perhaps as hard that the ufe of hard ioap is difcharged in Holland. many minutes ' Their junction with.the abfdrbent parti- faid, As there muft be a confiderable quantity of fea-falt in cles in the'cloth muft be immediate, whenever thefe acid this kind, which is not in the foft, and as this fait apparticles enter with the water. An unanfwerable proof that the fadt is fo, arifes from the circumftances which pears prejudicial to cloth, the foft foap ought to be pre-, happen when the cloth is firft fteeped in the vitriol-four; ferred. the cloth has no fooner imbibed the acid liquor than it The management of the coarfe cloth is very different, lofes all acidity, and becomes immediately vapid ’This in this operation, from fine. Inftead of being rubbed effedi of vitriol fours mull be of great advantage in the with hands, which would be too expenfive, it is laid on bl achfield, as the bleachers are at prefent hindered from a table, run over with foap, and then put betwixt the enjoying the feafan by the tedioufnefs of the fouring rubbing-boards, which have ridges and grooves from one procefs. The whole round of operations takes feven fide to another, like teeth. Thefe boards have fmali days; to anfwer which they muft have feven parcels, ledges to keep in the foap and water, which faves the which are often mixing together, and caufing miftakes. clqth. They are moved by hands, or a water-v. heel, is more equal and cheaper. The cloth is drawn, As three days, at moft, will be fufficient for all the ope- which degrees, through the boards, by men who attend j rations when vitriol-fours are ufed, there will be no more by than three parcels, 'fhe cloth will be kept a Ihorter or, which is more equal and cheaper, the fame waterwheel moves two rollers, with ridge and groove, fo that time in the bleachfield, and arrive fooner at market. • The milk-fours are very dear, and often difficult to be the former enters the latter, and, by a gentle motion got: but the vitriol are cheap, may be eafily procured, roond their own axis, pull the cloth gradually through the boards. and at any time. There is yet another advantage in the ufe of vitriol, This mill was invented in Ireland about thirty years and that is its power of whitening cloth. Even in this ago. The Irifli ble-ichers ufe it for their fine, as well as diluted ftate, its whitening power is very confiderable. coarfe cloatb. Thefe rubbing-boards were difcharged, We have already feen, that it removes the fame cblour- fome years ago, in Ireland, by the Truftees for the maing particles, which the alkaline lyes do. What of it nufactures of that country, convinced from long expethen remains, after the alkaline and abforbent particles rience of their bad effects. But as proper'care was not the bleach rs by degrees in a fafor meare neutralized in the cloth, muft adt on thefe colouring taken totheyinftruct continued in the old, made a party, and kept particles, and help to whiten the cloth. That this is thod, really the cafe, appears from the following fadh Mr poffeffion of the rubbing-boards. There were confideChryftie being obliged to chufe twenty of the whiteft rable improvements made in them in this country; fuch as the addition of the ledges, to keep the cloth moift; pieces out of a hundred, five of the twenty were taken and the rollers, which pull the cloth more gradually out of feven pieces which were bleached with vitriol. thanofmens hands. Thefe improvements were firft made From both experience and reafon, it appears, that it would be for the advantage of our linen-manufadture to in Salton bleachfield. The objections againft thefe rubbing-boards, are unufe vitriol in place of milk-fours. anfwerable. By rubbing on fuch an unequal furfaCe, the fibrous part of the cloth is wore; by which means Hand-rubbing' <nvith Soap and Warm Water, Rub- folid it is much thinned, and in a great meafure weakened bebing-boards*, Starching, Bluing. fore it comes to the market. As a proof of this, if the After the cloth comes from the fouring, it ffiouldbe water which comes from the cloth in the rubbing-boards well waflied in the waihing-mill, to take off all the acid be examined, it will be found full of cottony fibrous particles which adhere to its furface. All acids decom- matter. Thefe boards give the cloth a cottony furface, pofe foap, by feparating the alkaline fairs and oily parts fo that it does not keep long clean. Again, they flatten from one another. Were this to happen on the furface the threads, and take away all that roundnefs and firmof the cloth, the oil would remain ; nor would the wafii- nefs, which is the diftinguifhing property of cloth bleached in the Dutch method. ing-mill afterwards be able to carry it off. From the waffiing-mill the fine cloth is carried to be For thefe reafons they muft be very prejudicial to fine rubbed by womens hands, with foap and water. As the cloth, and fliould never be ufed in bleaching it. As liquors, which are generally employed for fouring, are they fe^m to be, in fome meafure, neceffary to leffen the impregnated with oily particles, many of thefe muft expence of bleaching coarfe linen, they ought never to lodge in the cloth, and remain, notwithftanding the pre- be ufed above'twice, or thriee at moft. They might be ceding milling. It is probable, that all the heavy oils rendered much more fafe, by lining their infides with are not evaporated by bleaching. Hence it becomes ne- fome foft elaftic fubftance, that will not wear the cloth ceffary to apply foap and warm water, .which unite with, fo much as the wooden teeth do. Mr Chryftie at Perth diffolve, and carry them off. It is obferved, that if the has lined his boards.with fliort hair for fome years paft, cloth, when it is pretty white, gets too much foap, the knd finds that it anfwers very well. following bleaching is apt to make it yellow; on that ac- After the coarfe linen has undergone a tubbing, it fltould be immediately milled for an hour, and warm count they often wring out the foap. It is a matter worth inquiring into, whether hard or water poured now and then on it to make ;t lather. This fiifx idap is heft for cloth. Moft bleachers, agree, that milling has very good effects; for it cleans the. doth af all.