l8o On the Art Df Dying by coloured Oxydes of Tin, 



water, the excefs of acid being abforbed by adding one-eighth part of carbonate of lime, while the 

 liquor is hot. Either of thefe procefibs with the alkaline folution of the carmine red oxyde, afforded 

 by muriate of thi and an infufion of cochineal, produce nearly the fame faadeof carmine, inclining 

 to crimfon. The {hade, on the contrary, will be poppy colour, if, inftead of the muriatic folution, - 

 the nitro-muriatic folution of tin be added, diluted with the fame quantity of water; to which, 

 in order to prevent fpontaneous precipitation, one-fourth of the muriate of foda has been added. 

 Thefe colours are as folid as the oxydes from which they arife." 



Citizen Hauflman then gives a detail rcfpecling the fhades of colour, of infinite variety, 

 which may be obtained from the various mixtures of the alkaline folutions of coloured oxydes: 

 very beautiful fcarlet reds are afforded by a mixture of the folution- of the carmine oxyde, with 

 that of the oxyde coloured by yellow wood. The folutions of indigo made by means of 

 arfcnic, antimony, or muriate of tin, may be ufed, but not thof; made by the fulphurets of the 

 fame metals, becaufe the immerfion of the piece-goods, which muft afterv/ards be made in the 

 muriatic folution of tin, or in that of the fulphate of alumine, would precipitate tlie fulphurets, 

 and render the colours obfcure. 



The {hades of green, of violet, and of prune mcnfieur, are particularly remarkable ; the blue 

 grounds can fcarcely be obtained of an even tinge but in the vats. The folutions of indigo, 

 gummed, and applied either alone or mixed with other coloured folutions, being ufually un- 

 equal; too much excefs of alkali in the blue folutions would render the colours dull. . 



A fine blue may likewife be produced without the folution of tin, by that of <Tummed 

 indigo, dried on the piece, and afterwards flecped in the folution of fulphate of alumine: aa 

 ingredient affording a yellow colour will complete the defired {hade of green. 



Some of the coloured oxydes of tin, prefent fingular facts ; that which is coloured by fer- 

 nambouc becomes clear and pale as it dries on the piece, but the colour becomes of a deep 

 red by immerfion in a folution of fulphate of alumine: a fimilar operation caufes the colour 

 from campeachy wood to become a deep violet, from a bright reddilh grey. 



The alkaline folution of the oxyde of tin, coloure.d by madder, requires more precautions 

 for its fuccefs than the foregoing, and perceptibly differs from them in its properties. The 

 author defcribes the moft proper method of obtaining the infuGon of madder, to which, a 

 proportionate quantity of carbonate of potafh is added ; the coloured oxyde is obtained by 

 mixing it with the muriatic folution of tin : but in order to obtain an intenfe colour, it is 

 abfolutely neceffary to filter and dry the oxyde before it is dilTolved in the potafh. By 

 treating this folution in the fame manner as was diredled for that of the carmine oxyde, by 

 means of the folution of the fulphate of alumine, and not that of the muriate of tin, which is not 

 applicable to the prefent experiment, a (liade of fuperf ne pulverized madder is obtained ; by 

 boiling with bran and water, the (hade, known in manufadories by the name of the fecond red 

 avill be obtained, which will become brighter by the addition of gum-water. 



The alkaline folution of the oxyde, coloured by madder, when it is well made, is fufficiently 

 confiftent to be ufed without gum. 



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