ulations respecting the
best mode of using it are confirmed by modern authorities. Gamboge, he
observes, furnishes a beautiful yellow, constant, unfading, and that works
freely."

We are not surprised to see another pigment commended; we have long used
it, but believe it is unknown as a colour by the artists of the present
day, though, we suspect, sold by colour-makers for common work as a cheap
brown. It is common coal. De Mayerne says, "The shadows of flesh are well
rendered by pit-coal, which should not be burned." It is also recommended
by Van Mander, and by Norgate, "whose directions for oil painting
correspond in all outward particulars with the Flemish methods." In some
experiments recorded by Sir Joshua Reynolds--there are the words "Gamboge
and oil--but no colour remains;" yet it should be observed that where it
is protected it is most durable. We believe the Aloes Cavallino, spoken of
in terms of commendation by Leonardo da Vinci, to be an excellent
transparent colour--and well calculated to give great richness to browns
and to greens. It is certainly very interesting to know the colours
actually used by the best masters of bye-gone days,--but we must not
forget that modern science may greatly have improved many, and produced
others, and has surer grounds to pronounce on their permanency. Mr Field,
in his Chromatography, has rendered a very great service to art.

It is not only the varnish, or rather the gums which compose the
varnishes, that should be considered with great attention, in reviewing
this subject,--but the great stress which seems to have been universally
laid upon the necessity of purifying the oils. And this necessity is
insisted upon from the earliest times. Even after all the precaution and
pains taken to purify oils, there will be a tendency to turn yellow upon
the surface. Rubens, in a letter, speaks of this, and gives orders for his
pictures, which were packed freshly painted, to be exposed to the sun. And
this practice of exposure to the sun seems to have been adopted generally
in Italy, as well as elsewhere, not only for the purpose of drying the
paint more readily, but for the freeing the surface from the yellowing of
the oil, the deleterious portion of which is thus taken up by the
atmosphere and the heat of the sun.

We have unhesitatingly exposed the surfaces of freshly painted pictures
not only to the sun, but to all weathers,--and that not for a few hours
but for weeks--and alway