The artists repository and drawing magazine: exhibiting the principles of the polite arts in their various branches (2.1788)

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Litmus may be thus prepared for ufe : boil an ounce
in a pint of fmall-beer wort till it is of a proper colour;
then pour off the liquor, and let it cool: by degrees it
will become folid. This may be liquefied by water,
and ufed.

LOGWOOD furnifhes a tincture of an excellent
purple colour : To obtain which fome proceed thus:

Boil together Brazil-wood and logwood, till the liquor
is of a due colour. More logwood makes it more pur-
ple ; more Brazil-wood inclines it to red. Or thus:

Boil two ounces of logwood in three pints of water ;
it is now brown, but by the addition of rock alum one
ounce, it becomes purple.

MASTICOT is lead gently calcined till it becomes
more or lefs yellow.

METAL, Dutch, is ufed where genuine gold
would be too expenfive. Shells id. each.

MILINUM, famous for being the only white of the
ancient artifts, is a fine white marley earth of a com-
pact texture, and remarkably light. It is found in the
Eaft.

Since white lead is fo very deceitful in water-colours,
might not this, or an earth of the fame fpecies, well
fupply its place ?

OCHRES are an extenfive genus of earths. The
moft common are yellow and red: but there are like-
wife blue, brown and green Ochres : and of thefe feveral
diftinctions. Dr. Hill defcribes of red, eleven forts ;
of yellow, the fame number; cf blue, and green, one
each, and of black two.

There