B L A 



ffiaking the vend, is difFufed again throcgh tlie liquor, and 

 tinges it of iti former colour. Wlien the nuxture is of a full 

 blacknefs, this feparation does not happen, or in a far lefs 

 degree ; for though a part of the black matter precipitates 

 in {landing, yet fo much remains diffolved, that the liquor 

 continues black. This fufpenfion of the colouring iub- 

 ftance in the black liquid may be attributed in part to the 

 gummy matter of the aftringent infufion increafing the con- 

 fiftencft of the watery fluid, for the feparation is retarded in 

 the diluted mixture by a frKall addition of gum arable. If 

 the mixture, either in its black or diluted Hate, be poured 

 into a filter, the liquor paffcs through coloured, only a part 

 of the black matter remaining on the paper. The filtered 

 liquor, on llanding for fome time, becomes turbid, and full of 

 fine black flakes: but being freed from thefe by a fecond 

 filtration, it again contracts th.e fame appearance, and thus 

 repeatedly, till all the colouring parts are leparated, and the 

 liquor has become colourlefs. The colouring matter, thus 

 feparated from the liquor, being drained on a filter and 

 dried, appeared of a deep black, which did not feem to have 

 fufftred any change on being expofed to the air for upwards 

 of four months. When it was made red hot, it glowed and 

 burnt, though without flaming, and became a ruily brown 

 powder, which was readily attratled by a magnetic bar ; 

 though in its black Hate, the magnet had no action upon 

 it. The vitriolic acid, diluted with water, and digeftcd on 

 the black powder, diffolved the greateft part of it, leaving 

 only a very little quantity of whitifh matter. Solution of 

 pure fixt alkaline lalt diffolved very little of it ; the liquor 

 received a reddifh brown colour, and the powder became 

 blaekilh brown. This refiduum was attracted by the magnet 

 after being made red-liot, though not before ; the alkaliv.e 

 tinilure, paffed through a filter, and mixed with folution of 

 gum vitriol, ilruck a deep brownilh-black colour, nearly the 

 fame with that which refults from mixing with tlie vitriolic 

 folution an alkaline tinclure of galls. For an account of 

 the refult of thefe experiments, fee Lewis, iiii fupra. See 

 alfo Iron. 



For broad-cloths, fine ratines, and druggets, &c. the 

 dvers ufe woad and indigo ; the goodnefs of the colour con- 

 fills in there not being above fix pounds of indigo to a ball 

 of woad, when the latter begins to caff its blue flower ; and, 

 in its not being heated for ufe above twice. Thus blued, 

 the ffuffis boiled with alum, or tartar, then maddered ; and, 

 lallly, the black given with galls, copperas, and fumac. To 

 bind it, and prevent its fmearing in ufe, the fluffs are to be 

 well fcoured \u the fulling mill, when white, and/kveil waflied 

 afterwards. 



For ftufFs of lefs value, it is fufllcient they be well blued 

 with woad, and blacked with galls and copperas : but no 

 fluff can be regularly dyed from white into black, without 

 pafiing through the intermediate blue. 



Yet there is a colour called coal hlacl, or jfefuit's Mack, 

 prepared of the fame ingredients as the former, and fufSeient 

 of itfelf without the blue dye. Here the drugs are diffolved 

 in water that had boiled four hours, and flood to cool till 

 the hand would bear it ; then the ituff is dipped in it, and 

 aga'in taken out fix or eight times. Some even prefer this 

 black to the other. This method of dying black is faid to 

 have been invented by the Jefuits, and to have been praftifcd 

 in their houfes, where they retained numbers of dyers. 



I?y 23 El. c. 9. nothing of the nature of cloth fliall be 

 niadd.ered for a black, except it be firft grounded with woad 

 only, or with woad and antle [blue ind.], unlefs the madder 

 be put in with fumac or galls ; on pain of forfeiting the 

 value of the thing dyed ; provided it ihall be lawful to dye 



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any manner tf gall-black, and fumac-black [//a/'n blacllt 

 wherein no madder fnall be ufed. 



Logwood (Irikes a black with chalybeate folutions and 

 is employed with thofe liquors for llaining wood black, as 

 pifture frames, Sec. With the addition of galls, it is ufed 

 for dying cloth and hats black. (Neumann's Works, 

 p. S^J.) This black colour is not permanent, though beau- 

 tiful, any more than the natural violet dye of the logwood. 



Black may be alfo obtained by a folution of filver in 

 aqua fortis, when the previous matter ftained with this liquor 

 is expofed for fome time to the fun and air ; and alfo from 

 folutions of lead in acids, when the fubjecls to which thev 

 are applied are expofed to fulphurecus vapours, or wafhtd 

 over with alkahne folutions of fulphiir. Calces of lead, 

 melted with fulphur, form a bluifh or blackifh mafs, ufeful 

 in taking c.ills from n-.edals. (See Casts.) Befides, when 

 a folution of filver in aqua fortis is added to a folution of ful- 

 phur made in alkaline ley, the filver and fulphur unite and 

 precipitate together in the form of a black powder. Sec 

 Dying, and Staining. 



Black, earth, is a kind of coal found in the ground, 

 which, well pounded, is ufed by painters in frcfco. See 

 Pit-CoAL, and Fresco. 



There is alio a kind of black made of filver and lead, ufed 

 to fill up the ftrokes and cavities of things engraved. 



Black, German, or Frankfurt, is made of the lees of wine 

 burnt, then waflied in water, and ground in mills for that 

 purpofe, together with ivory or peach ftones burnt. Some 

 fuppofe, that it is the coal of vine-twigs ; but this, fays 

 Dr. Lewis (Com. Phil. Techn. p. 377.), does not appear to 

 differ, in any great degree, from that of the fmall branches 

 of other kinds of trees ; but the kernels of fruits yield a coal 

 confiderably more foft and mellow, eauly crumbling between 

 the fingers into a fine meal. That the Frankfort black is 

 no other than a vegetable coal, appeared, from its burning 

 on a red-hot iron, like charcoal powder, into xvhite allies, 

 and from the aflies, like common vegetable allies, being plen- 

 tihilly difiohible by the vitriolic acid into a bitterilh liquor, 

 while the aflies of animal fubllances are very fparingly 

 affected by that acid, and form with it a compound of a 

 different kind of tafte. 



This black makes the principal ingredient in the rolling- 

 prefs printers' ink, which fee. It is ordinarily brought from 

 FVankfort, Mentz, or Strafbourg, either in lumps or powder. 

 That made in France is more valued than that of Germany. 



Black ^At/}. See Glass. 



Black, harts, that which remains in the retort after ex- 

 trafting the ipirit, fait, and oil of hartfliorn. This refidue 

 being ground up with water, makes a' black not much in- 

 ferior to that of ivory. 



Black, JnJiaii. See Indian Ink.! 



Black, Ivory, is made of ivory burnt or charred, ordina- 

 rily between two crucibles well luted ; which, being thus 

 rendered perfcclly black, and in fcales, is ground in water, 

 and made into troches, or little cakes, ufed by the painters ; 

 as alfo by the jewellers to blacken the bottom or ground of 

 the collets, wherein they fet diamonds to give them their 

 teint or foil. Some recommend foaking the chips or {hav- 

 ings of ivory in hot linfeed oil, before it is charred. 



There are particular machines and contrivances for burn- 

 ing the ivory for thefe purpofes, by which the colour is 

 rendered more beautiful than that of the coal which remains 

 in the dillillation. Neumann. 



The goodnefs of ivoi-y black, which is the fineft of all the 

 charcoal blacks, may be perceived by its fulnefs, without a 

 blue call ; and by the finenefs of the powder. 



Id 



