224- OAK. 
reduced to powder, they might, in times of scarcity, 
be adopted as a substitute for bread-corn. By pres- 
sure an oil is obtained from them which may be used 
for lamps; and a kind of coffee is prepared from them 
in some parts of the Continent. 
The branches of the oak, as well as those of several 
other kinds of trees, are burned for the formation, of 
charcoal ; and it is a remarkable circumstance that the 
properties of charcoal, from whatever wood it maybe 
made, are nearly the same. One of the most remark- 
able of these is, that it is not liable to decay by age. 
Hence it was customary, with the ancients, to char or 
burn the outside of stakes, or other wood, which were 
to be driven into the ground, or placed in water. 
Charcoal may be preserved without injury for an almost 
indefinite length of time ; and, in the ancient tombs of 
the inhabitants of northern nations, entire pieces of 
charcoal are at this day frequently discovered. 
Besides the great use of charcoal in the composition 
of gunpowder, and to artists and manufacturers of dif- 
ferent kinds, it has lately been employed, with consider- 
able success, in correcting the rancid and disagreeable 
smell of train oil, so as to render it fit to be burned in 
chamber lamps ; and several manufactories of this oil 
have been established in the neighbourhood of London. 
Newly-made charcoal, if rolled up in clothes which 
have contracted a disagreeable odour, will effectually 
destroy it : and if boiled with meat beginning to putrefy 
will take away the taint. 
This substance is used by artists in the polishing of 
brass and copper-plates, for the drawing of outlines, 
and numerous other purposes. When purified, it forms 
perhaps the best tooth-powder that is known. The 
mode of purifying it is to reduce it to powder, wash it 
repeatedly with water, and then dry it by means of a 
strong heat in close vessels. This heat expels the 
foreign contents with which it is impregnated ; but 
however intense, if the vessels are closed, it in no re- 
spects alters the quality of the charcoal. 
