This little work is the outcome of a series of lectures delivered to a class of Practical Painters and Decorators at the Darlington Technical College. The majority of the students could not be accused of possessing even a most elementary knowledge of chemistry, and further inquiries have shown that such is the condition of affairs amongst painters generally; although, of course, there are notable exceptions, which serve to prove the rule, as the saying is. The appreciation with which these lectures were received encouraged me to publish the same in book form, in the h0pe of appealing to a much larger circle, and of thus creating a wider interest in the subject. It is all very well to tell the youthful painter that cadmium yellow may not be tinted with white lead, and that it is unwise to mix together Prussian blue and lime but he is very liable to forget such rules until he has, learned their force by bitter experience. If, however, he is made to understand wiry these pigments are incompatibles, his interest is awakened, and the subject presents itself to him in an entirely new light. Now, this can only be done by a judicious inclusion of chemistry into the curriculum of the painter.