DENDROLOGY. 291 



particular process, to prevent its staining the stockings : it is a 

 great error to assert that this color augments its value. From the 

 cellular integument of the black oak is obtained the quercitron, 

 of which great use is made in dyeing wool, silk and paper 

 hangings. This substance was first prepared as a dye by Dr. 

 Bancroft $ he has given it the name of quercitron, by which it is 

 now universally recognized. 



Before extracting the color from the bark, the epidermis, or 

 external covering, ought to be removed by shaving. The 

 remaining parts being then properly ground by mill stones, 

 separate partly into a light, fine powder, and partly into stringy 

 filaments or fibres, which last yield but about half as much color 

 as the powder, and therefore care should be always taken to 

 employ both together, and as nearly as possible in their natural 

 proportions, otherwise the quantity of color produced may either 

 greatly exceed or fall short of what may be expected. The 

 quercitron thus prepared and proportioned, says Dr. Bancroft, 

 will generally yield as much color as eight or ten times its weight 

 of the weld plant, and about four times as much as its weight of 

 the chipped fustic. The coloring matter, continues he, most 

 nearly resembles that of the weld plant ; with this advantage, 

 however, that it is capable alone of producing more cheaply all, 

 or very nearly all, the effects of every other yellow dyeing drug ; 

 and, moreover, some effects which are not attainable by any 

 other means yet known. The coloring matter of quercitron 

 readily dissolves in water, even at a blood heat. If the infusion 

 be strained and left at rest, a quantity of resinous matter subsides 

 in the form of a whitish powder, which produces the same effects 

 in dyeing as the part remaining in solution. The clear effusion 

 being evaporated and dried, affords an extract equal in w T eight to 

 about one twelfth of the bark from which it is obtained. Much 

 care, however, must be employed in procuring this extract, so as 

 to make it produce colors equal in beauty to those obtained 

 directly from the bark itself. If the evaporation be carried on 

 rapidly, and the heat be too great, the color is tarnished, probably, 

 as Dr. Bancroft conjectures, from the absorption of oxygen, the 

 color thus undergoing a sort of semi-combustion. On the other 



