iy8 Oil ihe Art of Dying by echuy^d Oxydes of Tin, 



pabic of decompofition, and in which the oxygen is afforded to the metal by the decompofi- 

 tion of water. The muriatic acid, and, which is flill better, the acetous acid, afFurd this ad- 

 vantage. 



The phofphoric, oxalic, gallic, and tartareous, acids prefented no valuable properties with re- 

 gard to theproduflion of thcfc colours. The preci, itates formed by the union of thefc acids 

 v^'ith the oxyde of tin do not difcolour the inftifion of cochineal. 



The quantity of water which may be ufed contributes likewife to the greater orlefs intimate 

 combination of the oxyde of tin v/ith colouring matters, and modifies the {hade which is af- 

 forded. For example, in the produftion of the carmine oxyds by the infufion of cochineal, too 

 little water afibrds a dull colour, and too much prevents the metallic oxyde from acquiring co- 

 lour enough ; fo that it may even be completely difcoloured by repeated wafhing. 



After having given a variety of interefting details refpcSing the coloured oxydes of tin, and 

 ■carefully related the eflential conditions for producing each of thefe oxydes in particular, the au- 

 thor purpofes to ufe, as a mordant in dying, the folution of the acetite of tin, which he prefers 

 obtaining by the cold mixture of the aqueous folutions of the acetite of lead, and the muriate of 

 tin in cryftals, in order that the acetous folutions of tin thus obtained may be very concentrated, 

 and loaded with the metal. We cannot do better in this place than copy the words of the 

 author, which will explain the nature of the operation, its importance, and the precautions it 

 requires. 



" In order to apply the acetic folution of tin upon cotton or linen, either by the block or the 

 " pencil, it is necefl'ary that it fhould contain gum, and be left at reft for feveral days (upon 

 * the piece), during which time it quits its acid folvent, and depofits its oxyde of tin, which 

 " by affinity of adhefion will remain fixed on the piece by attradling the oxygen of the atmo- 

 " fphcre. Before the piece is expofed to the dying action of any fubftance whatever with 

 *' heat, it mufl: be boiled a few minutes in bran and water, or with cow;-dung, after which it 

 " muft be walhed in running vrater. The colours to be produced will be diiFerent, according 

 " to the dying drugs rriade ufe of. Madder, vegetable kermes, cochineal, and fermambouc, will 

 «« afford reds of various degrees of beauty; the wood St. Martin affords a brown; logwood 

 <' various fhades of violet ; yellow wood, quercitron, yellow berries (graines d'Avignon), 

 « &c. &c. afford yellows. By mixing all thefe ingredients in different proportions, by wcak- 

 " ening the acetic folution of tin more or lefs with the gummed water, or by adding the acetic 

 « folution of iron, an infinity of (hades may be produced. It is effential to gum this mordant 

 " before it is applied on the linen or cotton. If this circumftance be forgotten, the colours 

 " will be lefs bright; the fame precaution muft be attended to when the acetic folution of alu- 

 " mine is added. But', on the contrary, filks and woollens impregnated with an ungummed 

 " folution, then dried for feveral days, and dyed with the beforementioned ingredients, exhi- 

 " bit very bright colours. Wool more particularly, dyed with cochineal, then palled through 

 «< boiling water, and afterwards wafhed, prefents the moft beautiful purple. . 



^ The intenfity of tliefe colours will be much iricreafed by ufmg the muriatic folution of tin, 



" inftcad 



