Olive Oil has the valuable property of permanently retaining a good colour; but this advantage is overbalanced by the almost impossi-bility of drying it, both which properties it communicates in mixture to other oils.

Whether an oil might not be obtained, of a drying quality and sufficient strength for oil-painting, which shall have the property of continuing permanently colourless, remains for research; yet, according to our present knowledge, it may be questioned whether oils do not uniformly change in colour in proportion to their natural power of drying; but whether the oil of cotton, expressed from its greenish-coloured seed, in the southern of the United States of North America, which is of a drying quality adapted to painting, be superior to other expressed oils in permanence of colour, etc, we have not had an opportunity of trying.