I 175 ] ^00 



'be turned on a cylinder; then pas.s it through cold soap suds. As th(. 

 price of Aleppo galls is high, white galls are often used, in the propor- 

 tion of eight or ten parts of nuts to two parts of Aleppo galls. Diers 

 have a caldron on purpose for black, and when the dying composition 

 is exhausted, they renew it by what they called a brevet, (refresher.) 

 When the deposite is considerable, it is taken out, and iron filings add- 

 ed to the liquid. The dying of the silk is finished by heating the cal- 

 dron containing ihe die, and stirring it, from time to time, to prevent 

 the sediment from heating too much. 



The liquor must not boil; add more or less gum and iron solution; 

 and, when the gum is dissolved, and the liquid nearly boils, it is left 

 for one hour; the silk, divided into three portions, is then immersed, 

 each portion in succession. The silk is lightly wrung three times, and 

 aired each time. The great point of this operation is, to press out the 

 liquor with which the silk is impregnated; and, when it is drained to 

 fill it again therewith; and, above all, to expose it to the air, which 

 deepens the color. After each portion of silk has been wrung three 

 times, the vat is to be heated, and more gum and copperas added, as at' 

 first. The reheating of the vat is called giving a fire. Two fires are 

 commonly given for a light black, and three for a deep die; and some- 

 times the silk is left in the vat, after the last fire, for twelve hours. 

 Commonly, thirty kilogrammes* of sjlk are died in one operation. 



This is technically called a heat. If half that quantity is died, only 

 one fire is required for a light black. The dying being finished, the 

 silk is rinsed on the rods according to art. 



When the silk is died, it must be softened, by immersing it for a 

 quarter of an hour in a solution of soap in water, in the proportion of 

 from two to three pounds of soap to one hundred of silk. The quan- 

 tity of water is not mentioned. It is afterwards wrung and dried. 



Chaptal says: "A very full, clear, permanent black, has been obtain- 

 ed by the employment of a solution of iron immediately after a strong 

 galling; the stuff is then immersed in a decoction of logwood, and next 

 into this decoction conjoined with a solution of iron and verdigris: and 

 this process is to be repeated till the black be very beautiful. With 

 this view, 110 lbs, 5 oz. 10 dr. of silk, 44 lbs. 2 oz. 4 dr. of gall-nuts, 

 66 lbs. 3 oz. 6 dr. of copperas, calcined to redness, the same quantity 

 of logwood, and 11 lbs. 9 dr. of verdigris, were employed. 



The silk is to be first wrung out of the galls, allowed to dry, and then 

 strongly shaken by the hands, in order to ventilate, and detach from, it 

 any adhering galls. 



The same process of rubbing, shaking, &c. is to be employed in re- 

 spect to the logwood bath ; and the silk is to be carefully washed after 

 each immersion in the solution of copperas. In the last logwood bath 

 is to be dissolved 2 oz. 15 dr. of gum arabic, to 1 lb. 4 oz. 4 dr. of silk; 

 the black is softened by passing the died silk through soap and water. 



It has been observed, that, by combining vegetable astringents with 

 the gall-nuts, a softer and more agreeable color was produced. OaV. 



- A kilogramme is 2 lbs. 3 oz. 5 drachms, avoirdupoi':' 



