_Flake-white, and white-lead, or ceruss._
For painting in encaustic, I mix always both together half and half;
flake-white alone is subject to raise too much little bubbles in
employing it with water, which the admixture of the other prevents;
besides, both together make a better and more solid body; tho’
flake-white is the whitest of the two, to use either alone I should
prefer the second. The Venetian or Dalmatian white-lead is by far
the best for all manner of painting; being prepared with a purer and
subtler acid it is whiter and purer than any other whatsoever, and
preferable to flake-white; next to it is the German or Dutch; French
or English ceruss are in general but indifferent, in experiments I
frequently found the latter to have one third of marle or chalk in its
composition; which is the cause of its growing so soon yellow, dull
and dirty in oil.
In composing of the crayons it will be well to observe the above
mentioned proportion of half and half, as by the doing so, much pipe
clay will not be required to bind them.