Copper Mordants. 201 



quarter of an hour in soap suds, consisting of lib. soap in 

 300 lbs. water, the colour is changed into a gray-brown, 

 resembling quercitron-brown. 



Solution of potqLsh makes a faint whitish gray spot which 

 vinegar nearly dissolves. 



Ammonia dissolves the dye and makes it violet. 



Lime-water and vinegar have no action. 



Lime-juice produces a yellowish spot with reddish borders, 

 which becomes grayish-white by the action of ammonia. 



Tin mordants^ No. 1 and 2, printed upon it produce a 

 very brilliant crimson, which is very clearly distinguished 

 upon the blue-gray ground. 



Chloride of lime printed upon it gives a dark nankeen 

 colour. 



COPPER MORDANTS. 



Sulphate of copper does not combine with the calico 

 fibre, and is useless as a mordant. 



Acetate of copper, formed from sulphate of copper and 

 sugar of lead, is not much better, as it only enters into com- 

 bination with the fibre in very small proportion. 



On the contrary, however, ammoniuret of copper com- 

 bines readily with the calico. To produce this combina- 

 tion 8 lbs. of sulphate of copper are dissolved in 26 lbs. of 

 solution of ammonia of specific gravity 0*897, the vitriol 

 being added gradually, and stirred, until it is all dissolved. 

 The azure-blue solution is then to be well covered and 

 allowed to clarify. 



This mordant is termed Copper Mordant, No. 1. 



It answers when thickened with gum for printing a light 

 copper-blue and the metal green. 



When the calico is impregnated with this mordant and 

 washed, after remaining some days in the air, it is found to 

 be so strongly mordanted as to give very dark colours ; 

 unfortunately, however, they are not regularly produced, 

 and have mostly an earthy, dull appearance. 



The object is, therefore, better obtained by employing the 

 mordant diluted with water, and without allowing the 

 calico (impregnated with it and passed between two rollers) 

 to dry, to wash it immediately. In this case, the copper 

 mordant combines equably with the calico. 



