What makes the problems of marine painting so complex is, first of all, the fact that the sea is never in absolute repose, and therefore its surface forms are constantly undergoing some degree of change. Another difficulty is that the sea-water seems to vary in composition and consistency according to the conditions under which it is viewed; at one time it is solid, opaque, ponderous, and sombre in colour, and at another it is light, transparent and full of delicate tints. As it is a reflecting substance as well as one through which light can pass it alters in appearance in the most surprising manner under the incidence of sunlight or in response to the variations in atmospheric effect; and as it is a moving body it appears to be subject to no laws of construction and to have no sort of method in its restlessness. Most people, indeed, would hold that the cynical comment on womankind, “Toujours femme varie, souvent elle est folle,” could be applied with particular appropriateness to the sea, so feminine is it in its charming irresponsibility. Yet the student of the sea can, if he sets to work in the right way, discover the sources of its irresponsibility and the reasons for its lapses into insanity. He can dissect its forms and learn its anatomical construction, and he can find out what regulates and determines its movements. He can establish a direct agreement between the apparent texture of the sea and the bottom over which it flows, as well as between its surface character and the nature of the weather. And having dissected and analysed, having investigated and arranged his discoveries in the proper order, he can solve pictorial problems which ordinary men would count as puzzles to which there was no key. With this knowledge at his disposal he would be able, too, to paint pictures which would show the sea as it is and as it can be, not as an erratic and unaccountable phenomenon acting contrary to all natural laws, which is the view given of it by the artists who are incautious enough to paint it without having learned its ways. For instance, the painter properly equipped would make the right distinction, both in colour and wave form, between the deep sea and that in shallow places; between the transparency of waves breaking on a rocky coast and those on a sandy beach; between the wave action in a tidal current moving with or against the wind; or between the seas that are penned in a narrow channel and those that are running free in wide spaces. These are elementary matters, perhaps, in the study of marine painting, but elementary or not they are only too often misapprehended by the careless observer; and they are typical of a host of others which are not less likely to become pitfalls for the unwary. Neglect of them leads to slovenly and unsatisfactory production and to a kind of work that may be cheaply effective but that has actually no justification for existence.