197 i_ 175 ] 



When our object is to obtain the royal blue, which is also very deep 

 and permanent, cochineal is employed in place of savory. 



This last blue may be successfully imitated, by .first immersino- the 

 silk in a solution of 1 oz. 7^ drs. of verdigris, to 1 lb. 4 oz. 4 drs. of 

 silk; the silk is afterwards disposed in a bath of logwood, in which it 

 assumes a blue color, which is fixed by passing it through the vat. 



Silk to be died blue, is usually boiled in a bath composed of 44 lb. 

 2 oz. 4 drs. of soap, to 110 lb. 5 oz. 10 drs. of silk; it is carefully 

 washed, and twice put through running water, after which it is made 

 up into skeins, and plunged into the vat by means of the wooden roller, 

 until it has acquired the desired shade. It is then wrung by the hand, 

 shaken out in the air, afterwards washed, and again wrung and hung up 

 to dry. 



When silk is to be died blue without boiling, the whitest kinds are 

 chosen; they are dipped in water with a view of disposing them more 

 readily to imbibe the die. 



Yellow. * 



Alum, 3 oz. to 1 pound of silk; sugar of lead, 1 oz. to one pound of 

 alum; fustic, one pound, to one of silk; water, one or two gallons, in 

 proportion to the required shade. Immerse the silk over night in the 

 solution of alum and sugar of lead, take it out, wring and die it in 

 the fustic: the high price of weldt prevents the use of it; when used, 

 the proportion is the same as that of fustic. 



Chaptal says, that silk intended for a yellow color, is boiled with 

 22 lbs. 1 oz. 1 dr. of soap, to 110 lbs. 5 oz. 10 drs. of silk; it is after- 

 wards washed, alumed, and put on the rods. 



The yellow bath is prepared by boiling 2 lbs. 3 oz. 5 drs. of weld to 

 the pound of silk, during a quarter of an hour. This bath is strained 

 through a sieve, and cooled until the hand can be kept in it, before the 

 silk is immersed in the vat. 



The weld is boiled a second time, with a fresh portion of water, and 

 employed to supply the waste, and keep up the heat of the first bath, 

 into which more silk is put until it be sufficiently exhausted. 



With the view of extracting every particle of color from the weld,|. 

 and of imparting a golden hue to the yellow produced by it, 1 lb. 4 oz. 

 4 drs. of potash, to 22 lbs. 1 oz. 2 drs. of silk, are put into a caldron; 

 the second bath of weld is poured boiling hot on these ashes, and well 

 stirred, to hasten the solution. When the bath is become clear, they 

 gradually transfer a portion of it to the first bath, and after stirring it 

 again, immerse the silk. A golden hue may be imparted to yellow b}' 

 means of annotto.§ 



The United States abound in vegetables producing a yellow color, 

 and, with proper mordants, may be found highly valuable, 



* Mr. John Dougal. 



f The weld plant should be cultivated by our farmers: no crop will pay better 



* Absurdly called " woad," in the London translation of Chaptal . 

 ~? Chemistry applied to the Art?, p. 484. 



