my object in introducing them has been different, for I trust that (in some cases, at least) the easy experiments I have recorded will be tried, especially with suspicious pigments. The operations require but little time; the pieces of apparatus needed, like the chemicals, are few and inexpensive. And when the ease with which these testings can be made has been proved by practice, the experimenter may perhaps be induced to proceed a little farther, preparing his own siccative oil, selecting and purifying his spirit of turpentine, and so forth. That the painter should test the varnishes he buys for hardness and toughness, and the pigments for durability, may, I hope, be taken for granted.
'Titian managed pretty well without chemistry, did he not?' A distinguished artist asked me this question the other day. But not only were the conditions under which the painters of Titian's time worked simpler than those of the nineteenth century, but grounds, paints, oils, and varnishes were generally prepared in the studios of the artists, and under their own superintendence, so that the chances of going wrong were comparatively limited. Audit is not to be denied that a better acquaintance with the nature of the materials which many of the old masters employed would have caused their works to be handed down in sounder preservation to future generations.
It is possible—I hope, indeed, it is probable—that this book may be found of service to students who are purposing to devote themselves to certain manufacturing and technical pursuits. I am aware that to those who refer to
