Process for dyeing a fine Mineral Yellow Colour. 181 



sand-paper, and with this rubber make the surface of the paper 

 quite evni and smooth. Then paste on an inside sheet, which 

 must be quite free from spots or dirt of any kind ; cut off the 

 projecting edges as before, and when dry, rub it with fine glass- 

 paper, which will produce a perfectly smooth surface. Now take 

 half a pint of the size (No. 1), melt it by a gentle heat, and then 

 stir into It three table-spoonfuls of fine plaster of Paris • whci 

 the mixture is completed, ^our it out on the paper, and with a 

 soft "et sponge distribute it as evenly over the surface as possi- 

 ble. Then allow the surface to dry slowly, and rub it again with 

 ftne glass-paper. Lastly, take a few spoonfuls of the size (No I) 

 and mix it with three-fourths its quantity of water; unite'the 

 two by a gentle heat, and when the mass has cooled, so as to be 

 m a semi-gelatinous state, pour about one-third of it on the sur- 

 face of the paper, and spread it evenly with the sponge: when 

 this has dried, pour on another portion, and afterwards the re- 

 mainder: when the whole has again become dry, rub it over 

 lightly with fine glass-paper, and the process is completed : it 



for ^u'<=^"° "^ ^'' ^^ ''"' ^""^^ ^''°'" ^^^ ^^^^ °*''^^*^^ *"^ '' ^^^^y 



The quantity of ingredients above mentioned is sufficient for a 

 piece of paper 1/ and a half inches bv 15 and a half 



Paris plaster gives a perfectly white surface; oxide of zinc, 

 mixed with Pans plaster, in the proportion of four parts of the 

 former to three of the latter, gives a tint very nearly resembling 

 Jvory; precipitated carbonate of barytes gives a tint intermediate 

 between the two. 



^^^J.' P^'^'^^'for gj^j^g to Linen, Silk, Cotton, &?c, a fine 

 Mineral Yellow Colour. By M. Henri BracoxVnot*. 



HiXCEPriNG Prussian blue, which we have not as yet been able 

 to impart to all cloths, the prussiate of copper and oxide of iron, 

 which give colours rather more solid than brilliant, all the other 

 colours used m the art of dyeing are drawn from the organic 

 (vegetable) kingdom, because they are generally easier applied 

 than minera colours, although more or less alterable in the course 

 o\ time. 1 he yellows are more subject to this sort of change- 

 ableness ; and if the madder colour with the help of mordants 

 acquires in the end a certain stability, it is always at the expense 

 o\ Us first brilliancy. ^ 



The mineral substance which I have succeeded in fixing on 

 cloths, and which I now recommend to dyers as the most bril- 

 • From the Am. tie ChmU, Dec. 1819. 



M 3 liant 



