Prussiate of Potash. 285 



mix 104 loths (46-9 ozs.) salt of tin, with 136 loths (63-78 

 ozs.) of crystallized acetate of soda. 



It is improper to keep any stock of acetate of tin, as it is 

 very readily decomposed, but it should be first formed in the 

 dye. The salt of tin, should, therefore, be mixed first, and 

 immediately before printing, the necessary quantity of acetate 

 of soda should be added, and both stirred well together. 



If a solution of tin be mixed with alum, decomposition 

 ensues, and sulphate of tin precipitates in the form of a 

 white powders Both should not, therefore, be employed 

 together. Should this, however, happen, the solution of 

 the salt of tin may be added before the sulphuric acid, in the 

 proportion of 104 loths (48*77 ozs.) salt of tin, and 25 loths 

 (1T7 ozs.) sulphuric acid. Sulphate of tin is formed, which 

 is miscible with the solution of alum. When salt of tin 

 is mixed with a solution of soap, the tin separates in com- 

 bination with the oil of the soap. Notwithstanding this 

 decomposition, this mixture affords a very useful solution 

 for clearing madder-purple and Turkey-red. The propor- 

 tions are 4 loths (1-87 oz.) to 3 or 400 loths (187- ozs.) 

 oil soap, which should be dissolved in a great quantity of 

 boiling water before adding the salt of tin. 



The mordant which occurs in this treatise, underthe name 

 of tin mordant, No. 1, consists of 10 lbs. salt of tin, 10 lbs. 

 water, and 10 lbs. muriatic acid. It is an excellent dis- 

 charger of colourless grounds, especially, of iron mordants. 



If we dissolve 104 loths (48'77 ozs.) of salt of tin, in 200 

 loths (93*8 oz.) water, and saturate the solution by a stream 

 of chlorine gas, a salt of tin is formed, called per-chloride 

 of tin. It answers equally well as a discharger, (Tin mor- 

 dant, No. 2), but, especially, as an addition to colours 

 printed by the block. This per-chloride of tin, may be 

 converted by means of acetate of soda, like salt of tin, into 

 a less corrosive acetate of tin. 



As the per-chloride of tin contains twice the quantity of 

 chlorine contained in the salt of tin, it is necessary, in 

 order to convert it into an acetic acid salt to employ twice 

 as much acetate of soda. We must, therefore, add to the 

 above quantity 272 loths (127J ozs.) In this case also, 

 the necessary quantity of acetate of soda, should be added, 

 immediately before applying it to the print. 



Prussiate of potash. — This salt, constituting a well-known 



