s with advantage. There is another method also
which will be found equally beneficial. When the surface is greasy, and
will not take water from the sponge, it may be truly conjectured that this
deleterious quality of the oil has exuded. We always remove it by sand and
water--the coarser the sand the better; the finer, being more silicious,
is more likely to cut. But we must observe that even though the picture be
not fairly dry, excepting under very rough usage, the paint will not be at
all removed. Even after this cleansing, the oil will still, for a
considerable time, throw up this greasy product. We remove it, therefore,
again and again until, after a week or ten days' trial, we find the
surface free from grease; and we are strongly inclined to think the
colours undergo no change when this clearance has been once well effected.
In a letter from Mrs Merrifield, she strongly recommends this exposure of
pictures to the sun and atmosphere; and says it was universally practised.
This should not, however, prevent the previous purification of the oils;
for there is no writer upon the subject that does not insist upon this. Mr
Eastlake's book furnishes recipes of all ages. Frequent washings with
water, to which a little salt is added, and fine sand to take down the
impurities of the oil, may be safely recommended. In describing the
process taught by the Gesuate, friends of Perugino, the Padre Gesuato
adds, "Observe, that wherever you find oil mentioned, this purified oil is
meant."

It would appear that the pigments were, formerly as now, ground only in
oil: the vernix was added to the colour, by drops, when on the palette; so
that, should the new, or recovered old vehicles, if such they be, come
into general use, it will not be necessary to discard the supply of oil
colours from the shops of our colour-makers. The colours in tubes, which
happily have superseded the bladders, will still be in general request.
Northcote thought it a great advantage to the old Italian masters that
they were under the necessity of making most of their colours themselves.
This, certainly, was not the case in the earlier times; for the monks, who
were every thing--physicians, painters, chemists, &c.--were not only the
patrons and dealers, but were makers of the colours also. We cannot quite
agree with Northcote. The only objection we have to offer to the present
system of tube colours is as regards their cost; for, considering the
value of the mat