too, must be reckoned among the artificial colours,
although it is also derived in two ways from the earth.
For sometimes it is found exuding from the earth like the
brine of salt-pits, while at other times an earth itself of a
sulphurous colour is sought for the purpose. Painters, too, have
been known to go so far as to dig up half-charred bones2
the sepulchres for this purpose.
All these plans, however, are new-fangled and troublesome;
for this substance may be prepared, in numerous ways, from
the soot that is yielded by the combustion of resin or pitch;
so much so, indeed, that manufactories have been built on the
principle of not allowing an escape for the smoke evolved by
the process. The most esteemed black,3
however, that is made
in this way, is prepared from the wood of the torch-pine.
It is adulterated by mixing it with the ordinary soot from
furnaces and baths, a substance which is also employed for the
purpose of writing. Others, again, calcine dried wine-lees, and
assure us that if the wine was originally of good quality from
which the colour is made, it will bear comparison with that of
Polygnotus and Micon, the most celebrated painters
of Athens, made their black from grape-husks, and called it
Apelles invented a method of preparing it from
burnt ivory, the name given to it being "elephantinon."
We have indicum also, a substance imported from India, the
composition of which is at present unknown to me.6
too, prepare an atramentum from the black inflorescence which
adheres to the brazen dye-pans. It is made also from logs of
torch-pine, burnt to charcoal and pounded in a mortar. The sæpia,
too, has a wonderful property of secreting a black liquid;7
but from this liquid no colour is prepared. The preparation of
every kind of atramentum is completed by exposure to the sun;
the black, for writing, having an admixture of gum, and that
for coating walls, an admixture of glue. Black pigment that
has been dissolved in vinegar is not easily effaced by washing.