■nnd Dyeing Turhy Red. 26^ 



AH fat oils may be emplo\ed in the mixture with proper 

 precautions ; hut linfceil-oil mixes better, and remains longer 

 iufperided in the alkaline foliition of alumine : I never tried 

 fidi-oil, whieh, perhaps, would he preferable. It is probable 

 alfo, that in operating on a large fcale, it would be bed to 

 diminifh the quantitv of linfeed-oil in the n)ixtures with the 

 alkaline folution of aiumine ; for I have had reafon often to 

 obferve that too much oil hurts the attraction of the colour- 

 ing parts of the madder : a thirty-third part of linfeed-oil 

 always produced the beft efleS in my trials on a fmall 

 fcale. 



In rec^ard to the procefs of dyeing cottop. and linen thread, 

 fufficienlly chars;ed with alumine, by the oilv alkaline folu- 

 tion of that eartii, the ftains muft tirft be difengaged from 

 every faline fubdaiice, as well as from the fuperfluous oil, by 

 riniing them a long time in very pure running water; after 

 which they mud be arranged, without drying them, on an 

 apparatus, which the operator may conllrucl according to 

 the form of the boiler, — in which it is to be placed in fuch a 

 manner, that during the procefs of dyeing tlie flcains may 

 be continually fliakcn and turned, in order to catch every 

 where, and in an uniform manner, the colouring particles. 

 The bath mu(l be compofed of madder, mixed with a fixth 

 of pounded chalk, and diluted with about 30 or 40 parts of 

 water. The heat muft 'be carried only to fuch a degree that 

 the hand can be held in the bath for an hour without being 

 fcalded ; and it is to be maintained at this degree for two 

 Viours, either by diminifliing or increafing the fuel. Three 

 hours dyeing will be fufficient to cxhaull the madder : the 

 Ikains when'^taken from the bath mud be wafiied in a large 

 quantity of water to clcanfe them ; they are then to be cleared 

 bv boiling them a prettv long time in water contaiuing bran 

 inclofed in a bag, adding foap and alkaline carbon»te to give 

 the red a roly or carmine (liade. 



As I never had occafion to dye colton or linen thread on a 

 large fcale, I employed a ("mail boiler, which ferved me at the 

 fame time for the procefs of clearing: in the latter operation 

 I confined myft-lf to boiling the fkaiys, properly arranged, iu 

 water containing a bag filled with bran, for eight hours fuc- 

 ccflively; and, that I niight not interrupt the ebullition, I 

 replaced the evaporated part by the addition of more boiling 

 water. In this clearing 1 employed neither foap nor alkali ; 

 yet I obtaineii a red fuperjor in benuty and fixity to that of 

 the Levant, and which, "in every refpeft, will bear a coni- 

 parifoa with the bell colours dvecl in I'Vance. 



H ; For 



