FLOOR OF THE TANK. 9 



It is always best to build up the rock-work with 

 loose stones, placed upon the bottom of the tank 

 arranging them in such a manner, that not only 

 shelter, shade, &c., may be afforded to the contained 

 animals, but that they may be enabled to station them- 

 selves at any depth in the water which their habits or 

 choice may lead them to select. 



The best materials for this purpose will be found to 

 be pieces of granite or of limestone of various shapes 

 and sizes ; but all of such weight and regularity of 

 form, that, when placed one upon the other, in ac- 

 cordance with the taste or intention of the designer, 

 they may rest firmly and securely in their respective 

 places. No cement should be employed in the con- 

 struction of these mimic edifices ; their weight alone 

 and steady supraposition upon each other should 

 ensure the firmness and stability of the entire fabric. 



Rude bridges of Cyclopian masonry edifices some- 

 what after the pattern of Stonehenge and other Celtic 

 piles caverns of wave-worn rock and craggy terraces 

 should rise above each other, till the top, reaching 

 above the level of the water, forms a little island of 

 dry land. 



We will, however, now confine our attention to the 

 permanent Aquarium, and the mode of its establish- 

 ment. We suppose the rock-work to have been ar- 

 ranged in accordance with the shape and dimensions 

 of the tank, and scars and reefs, and cliffs and caves, 

 to be adequately represented without needlessly oc- 

 cupying the valuable space in the interior. 



The next step, of course, is to lay down the bottom 

 of our miniature sea, so as to adapt it to the comfort 



B 5 



