B 



Pi-Oi-efs for BU'achiiig R..w Si it. 



VIII. 



The Prcctfs far "ivirig a henut'ifitl White Colour ti R.liu SiO:, luilhout Scouring. 

 B)- M. D.lUMIi*. 



F.RTHOLLET, in liis Elemcns de I'Art dc la Tcintiire, publillied in the year 179T, 

 after defcribing the ufual methods of depriving fill; of its refinous or gummy matter +, -pro- 

 ceeds to remark, that, in tlie manufadiurc of blonds and gauzes, the natural elafticity and 

 ftiffhefs of this article, are re<julred to be prefcrved ; whence it has become a defideratum to 

 render the yellow filk of Europe white like that of China, without depriving it of its gum. 

 lie adds, that Mr. Baume has folvcd this interefting problem, but had kept his procefs a 

 fccrct ; but from the fads he had poflclVed the means of obtaining, it appeared liable 

 to accidents, and that the chief difficulty confillcd in giving an uniform white colour when 

 lar^e quantities were operated upon. He alfo mentions a diHiculty in dreffing the whitened filk 

 foas to prevent its curling, and obferves that it ought certainly to be kept conflantlyftretched 

 during the drying. It is befides rcquifite that the fpirit of wine fliould be recovered after 

 the procefs, which would clfc be rendered too expenfive. This author docs not fay whether 

 the white Chinefe filk is fubjecl to the fame inconvenience of curling when dyed, which, it 

 may be remarked, is a property of no confequence where the material is to be applied in the 

 manufacture of white goods. The motiveswhich led Mr. Baume to communicate his procefs 

 to the world, originally retained by him as a lucrative fecret, do not appear. Whether the 

 miftakes of thofe who carried it into efFefl in the large way might liave led him to vindi- 

 cate the reality of his difcovery by publication; or whether the commercial advantages 

 derived from fuperiority of quality and cheapnefs in his article over the Chinefe filk in the 

 market of France, might in the end have proved of Icfs value than the fcientific reputation 

 to be derived from its difclofure ; arc circumflances which will, no doubt, have their proper 

 weight with fuch manufafturers as may be induced gradually to adopt this procefs. 



The filk of Nankin is perfectly white, filvery, brilliant, and poflcfTes all the elaflicity of 

 raw filk. Our author atTirms, that the value of this article imported into Europe amounts 

 to upwards of twenty millions of livres J, of which France confumes about four or five 

 millions in gauzes, blonds, ribbons, &c. This was formerly fuppofed to be produced of a 

 white colour from the worm. The late Mr. Trudaine, intendant of commerce, procured 

 the eggs of the filk-worm from China, and cultivated them. The produce ccnfifled cf 

 yellow cocons, and others of the moft perfe£l whitenefs. - The latter afforded filk equal 

 in this refpeft to that of Nankin, But Mr. Baume affirms, that moft of the Nankin filk is 

 bleached by art, and, as he thinks, by a procefs fimilar to liis own. 



As it is impofiible to wind off a large quantity of filk in the (hort time previous to that of 

 the infe£ls eating their way through the mafs, it is ufual, in the firft place, to deprive them 

 cf life. This is commonly done by expofing the cocons, properly wrapped up, for two 

 hours to the heat of about 1 58 degrees of Fahrenheit in an oven ; after which they are 



• The original Memoirc from which the fafts here related arc taktn, is infcrted in the Journal dc Phyfiquc, 

 »'■'• 375—399- 



t Tom. i. p. 146; or p. 141 of Dr. Hamilton's trandaiion. 

 X Akxjut eight hundred and tliirty thoufand pounds fterling. 



kept 



