in and out of the recesses of the rocks or the thickets of the seaweed.  There is no end of the pleasant sights.  And day after day the creatures will grow more tame, the serpula will not dart back into his case when you approach, nor the pecten close his beautiful shell as your shadow passes over it.  Moreover, the habits of the creatures grow more entertaining as you become familiar with them, and even the dull oyster begins at last to show some signs of individual character.

And it is easy to have all this away from the seashore.  The best tanks, so far as we know, that are made in this country, are those of Mr. C.E.  Hammett, of Newport, Rhode Island.  But the tank is of little importance, if one cannot get the water, the seaweed, and the stock; and therefore Mr. Hammett undertakes to supply these also.  He will send, not the water itself, but the salts obtained by evaporation from the quantity of water necessary for each aquarium.  These are to be dissolved in clear spring-water, (previously boiled, to insure its containing no injurious living matter,) and then the aquarium, having first had a bed of cleanly-washed sand put upon its bottom for about an inch or an inch and a half in depth, and this in turn covered with a thin layer of small pebbles,—­though these last are not essential,—­is to be filled with it.  Then the seaweed, which is sent so packed as to preserve its freshness, is to be put in.  It will be attached to small bits of rock, and these should be supported by or laid upon other pieces of stone, so raised as to secure a free passage for the water about them, and so afford places of retreat for the animals.  The stock will be sent, if it is to go to any distance, in jars, and anemones, crabs, shell-fish of various kinds, and many other creatures, will be found among it.  The seaweed should be a day or two in the tank before the creatures are put into it.

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