And now, having got the aquarium in order, comes the point how to keep it in order,—how to keep the creatures alive, and how to prevent the water from growing cloudy and thick. The main rule is to secure sunlight,—hot enough to raise the water to a temperature above that of the outer air,— to remove all dirt and floating scum, and to furnish the tank on every cloudy day with a supply of air and with motion by means of a syringe. The creatures should never be fed in warm weather with any animal substance, its decay being certain to corrupt the water. A little meal or a few crumbs of bread may now and then be given; but even this is not necessary; for Nature furnishes all the food that is needed, in the spores thrown off by the seaweed, in the seaweed itself, whose growth is generally sufficiently rapid to make up for the ravages committed upon it, and in the host of infusoria constantly produced in the water. If any of the creatures die, their bodies should be immediately removed,—though sometimes the omnivorous crabs will do this work rapidly enough. As the water evaporates, it should be filled up to its original level with fresh spring-water,—the salts in it undergoing no diminution by evaporation. If, suddenly, the water should grow thick, it should be taken from the tank, a portion at a time, and filtered back into it slowly through pounded charcoal, the process being repeated till the purity seems to be returning, and at the same time the rocks and seaweed should be removed and carefully washed in fresh water. If, however, the water should by any ill chance grow tainted and emit a bad odor, nothing can be done to restore it, and, unless it is at once changed, the creatures will die. To meet such an emergency, which is of rare occurrence, it is well to have a double quantity of the salts sent with the tank to secure a new supply of water. But we have known aquariums that have kept in order for more than a year with no change of the water, a supply of spring-water being put in from time to time as we have directed; and at this moment, as we write, there is an aquarium at our side which has been in active operation for six months, and the water is as clear as it was the day it was put in. If, spite of everything, the seawater fail, then try a fresh-water aquarium. Use your tank for the pond instead of the ocean; and in the spotted newt, the tortoise, the tadpole, the caddis-worm, and the thousand other inhabitants of our inland ponds and brooks, with the weeds among which they live, you will find as much entertainment as in watching the wonders of the great sea.
A camel's-hair brush, a bent spoon on a long handle, a sponge tied to a stick, and one or two other instruments which use will suggest, are all that are needed for keeping the sides of the tank free from growth or removing obnoxious substances from its bottom.
If, on receiving the animals, any of them should appear exhausted by the journey, they may sometimes be revived by aerating the water in which they are by means of a syringe. It should always be remembered, that, though living in the water, they need a constant supply of air. And it would be well, in getting an aquarium, to have the tank and the seaweeds sent a few days in advance of the stock, so that on the arrival of the creatures they may be at once transferred to their new abode.
There are no American books upon the subject, and, in the present want of them, the two whose names are given above are the best that can be obtained. Mr. Gosse's is expensive, costing between four and five dollars. "The Common Objects of the Seashore," to be got for a quarter of a dollar, contains much accurate, unpretending, and pleasant information.
The American Drawing-Book: a Manual for the Amateur, and a Basis of Study for the Professional Artist. Especially adapted to the Use of Public and Private Schools, as well as Home Instruction. By J.G. CHAPMAN, N.A. New York: J.S. Redfield. 4to. pp. 304.
Drawing-books, in general, deserve to be put into the same category with the numerous languages "without a master" which have deluded so many impatient aspirants to knowledge by royal (and cheap) roads. A drawing- book, at its very best, is only a partial and lame substitute for a teacher, giving instruction empirically; so that, be it ever so correct in principle, it must lack adaptation to the momentary and most pressing wants of the pupil and to his particular frame of mind; it is too Procrustean to be of any ultimate use to anybody, except in comparatively unimportant matters. It is well enough for those who need only amusement in their drawing, and whose highest idea of Art is copying prints and pictures; but for those who want assistance from Art in order to the better understanding of Nature, no man, be he ever so wise, can, by the drawing-book plan, do much to smooth the way of study.
All that another mind could do for us by way of teaching Art would be to save us time,—first, by its experience, in anticipating our failures; second, by its trained accuracy, to correct our errors of expression more promptly than our afterthought would do it,—and to systematize our perceptions for us by showing us the relative and comparative importance of truths in Nature. In the first two respects, which are merely practical, the drawing-book, if judiciously prepared, might do somewhat to assist us; but in the last and most important, only the experienced and thoughtful artist, standing with us before Nature, can give us further insight into her system of expression. A good picture may do a little, but it is Nature's own face we need to study, and that neither book nor picture can very deeply interpret for our proper and peculiar perception.
In the practical part, again, the drawing-book can give us no real assistance in regard to color. And thus the efficacy of it is reduced to the communication of methods of drawing in white and black. This Chapman's book does to the best purpose possible under the circumstances, in what is technically termed the right-line system of drawing,—that is, the reduction of all forms to their approximate geometrical figures in order to facilitate the measurements of the eye. Thus, it is easier by far to determine the proportion which exists between the sides of a triangle formed by the lines connecting the three principal points in any figure than any curvilinear connections whatever. The application of the rectilinear system consists in the use, as a basis of the drawing, of such a series of triangles as shall at once show the exact relation of the points of definition or expression to each other; but the successful application of this depends much on the assistance of the trained eye and hand of a master watching every step we make.
When we leave this section of the "American Drawing-Book," we leave all that is of practical value to the young artist. The prescription of any particular mode of execution is always injurious, (if in any degree effective,) for the reason that the student must not think of execution at all, but simply what the form is which he wants to draw, and how he can draw it most plainly and promptly. Decision of execution should always be the result of complete knowledge of the thing to be drawn; if from any other source, it will assuredly be only heedless scrawling, bad in proportion as it is energetic and decided.
The chapter on Perspective is full and well illustrated, and useful to architectural or mechanical draughtsmen, may-be, but little so to artists. There are, indeed, no laws of perspective which the careful draughtsman from Nature need ever apply, for his eye will show him the tendency of lines and the relative magnitude of bodies quicker than he can find them by the application of the rules of perspective,—and with much better result, since all application of science directly to artistic work endangers its poetic character, and almost invariably gives rise to a hardness and formalism the reverse of artistic, leading the artist to depend on what he knows ought to be rather than on what he really sees, a tendency more to be deprecated than any want of correctness in drawing.