I. 1. THE BLACK OR YELLOW-BARKED OAK. 143 
resembling those of the scarlet oak, from which it cannot easily 
be distinguished but by the color of its inner bark. The third 
has leaves very broad at the extremity, and tapering much 
towards the base. These trees seem to be as different as the 
several varieties or species of the chestnut oak group. There 
are, probably, corresponding differences in the qualities of the 
wood. 
For ship-timber, the wood of the black oak is next in value 
to that of the oaks of the first division; and it is much used 
as a substitute for white oak. For floors and floor-timbers, it 
answers well, but is lable to decay, about iron. The grain is 
close and rather fine; the pores between the circles of growth 
are not large; the plates of silver grain rather wide and near 
together. It has, therefore, great strength, and is extensively 
used by wagon-makers and other manufacturers in wood, being, 
for some purposes, superior to white oak. 
The bark is highly valued by the tanner, as it abounds in 
tannin. It is liable, however, to the objection, that it gives a 
yellow color to leather, which is communicated to articles which 
remain long in contact with it. 
The bark is also much used in domestic manufactures, for 
dyeing. With various preparations. it gives a great variety of 
shades of tawn color and yellow. From the inner portion of 
the bark is obtained the substance called quercitron, which was 
first brought to notice by Dr. Bancroft, and is used as a substi- 
tute for weld, in dyeing on a large scale. The colors given are 
fast colors. By a mixture of other dyes, as cochineal, several 
other shades, all rich and delicate, are given by quercitron. 
This bark is not so highly valued as it should be. By means 
of it and the sumac, alders, birch, and some other barks, nearly 
all the colors necessary in dyeing might be obtamed without 
cost, as the time of those who would prepare it is not commonly 
applied to any productive object, at the season when the prepa- 
ration might be made. 
Upon the leaves of the black oak, as also those of the red 
and scarlet, are often found smooth, round, hght excrescences, 
called oak apples, one or two inches in diameter. They are 
formed by an extension of the cuticle of the leaf, which they 
