408 VEGETABLE SUBSTANCES. 



CHAPTER XXIV. 



BLACK DYES. 

 GALL-NUTS VALONIA MYROBALANS. 



SEVERAL substances are found in the vegetable world 

 which produce a permanent substantive black dye, 

 but these are of little importance in the dye-house, 

 since they cannot be collected in sufficient quantity to 

 be employed with advantage, the necessities of the art 

 requiring a much larger supply of black dye than could 

 thus be obtained. This dye is, therefore, in England 

 always the result of artificial combination. Among 

 the different colouring matters already described, the 

 application of some in the formation of a black dye 

 has already been noticed, and these, with different 

 mordants, are most usually employed. 



The Gall-nut is one of the principal ingredients 

 used in dyeing black and various kindred colours : it 

 is employed in large quantities in our dye-houses, 

 besides which it is an essential component in all 

 black writing-inks. 



Gall-nuts are the produce of a prickly cupped 

 oak, Quercus infectoria, a small timber tree, that 

 grows wild in almost all the countries bordering 

 upon the Mediterranean, and in some of the southern 

 provinces of Germany. Some notice of this tree is 

 to be seen in the volume upon timber trees, in the 

 present series. Galls are generally supposed to 

 originate from a puncture made by an insect of the 

 genus cynips. An authority, however, of much 

 weight in the scientific world would lead us to doubt 



