They are reached, in a greater or lesser degree, by all that large army of skilled and competent workers which carries out the work of the world in its manifold departments, and only a comparatively small number reach the third stage of abstraction; for when abstraction is reached, we have entered the sphere of genius. In the first two stages, the work and the mind are separate, and the work is done more or less laboriously, and with a degree of friction; but in the third stage, a marriage of the work with the mind takes place, there is a fusion, a union, and the two become one: then there is a superior efficiency with less labour and friction. In the perfection of the first two stages, the mind is objectively engaged, and is easily drawn from its centre by external sights and sounds; but when the mind has attained
