58 Mr. George on Fustic and its 



Chemic. The Annals of Philosophy contain an interesting 

 set of experiments made upon this combination by Mr. Crum. 

 I shall only state that the long list of substances employed by 

 the old dyers and chemists in making this solution are almost 

 entirely discarded, and sulphuric acid and indigo are the only 

 substances now employed. It is of great importance that the 

 sulphuric acid should be free from nitrous gas, which by its 

 action upon the indigo (deoxidizing) deprives the colour 

 produced of brightness and lustre. In making the solution of 

 indigo for greens an excess of sulphuric acid should be 

 avoided, as it prevents the yellow colouring matter fixing upon 

 the cloth. I have found 9lbs of sulphuric acid to lib. of in- 

 digo of good quality the best proportion. 



For the dyeing of lOOlbs. of worsted goods, known as Wild- 

 bores, a bright green. In a leaden vessel containing 300 gallons 

 of water — when at the temperature of 1 50° Fahrenheit, threw 

 in 25lbs of alum and 2 quarts of bran — carefully removed 

 the impurities that rose to the surface until the water boiled, 

 then added 2\ pints of sulphate of indigo; 12lbs. of fustic in 

 chips, and lOlbs. of white Florence argol (super- tartrate of 

 potash); boiled the whole five minutes, added 20 gallons of 

 cold water, and entered the goods, turning quickly for ten 

 minutes and then more slowly, at the same time raising the 

 temperature to ebullition. After boiling forty-five minutes 

 found the colour scarcely so full as required, and took out the 

 goods, adding half a pint of sulphate of indigo and 4lbs. of 

 fustic, again entered and boiled half an hour. Fresh goods 

 may be dyed in the same liquid ; indeed, in conducting a dye- 

 house oeconomically, it is of great consequence so to arrange 

 the colours that they shall follow each other without emptying 

 the dyeing vessels, as thus a great saving of dyeing wares is 

 achieved. For lOOlbs. of the same description of goods, and 

 the same shade of colour, — added 15lbs. of alum, 2\ pints of 

 sulphate of indigo, and 7lbs. of argol : after entering and boil- 

 ing as before 45 minutes, took out the goods, added half a 

 pint of sulphate of indigo ; entered and boiled twenty minutes. 

 It is of importance that the whole of the indigo should not be 

 given at first, since from the boilinfj necessary to oive even- 



111 J C) 



ness to the colour the lustre is considerably impaired : by 

 adding a part towards the close of the process both evenness 

 and beauty of colour are insured. For a third quantity, the 

 same colour, 12lbs. of alum were added, and the amount of 

 alum in a fourth and fifth quantity must gradually diminish to 

 6lbs. The amount of fustic and argol are to be graduallj'^ 

 reduced, the proportions depend, however, upon the discretion 

 of the dyer ; the proportion of sulphate of indigo remains the 



same. 



