56 



beach ; and if the latter plan is adopted, the stones should not be 

 obtained until the aquarium is quite ready for its living contents ; 

 for then a selection of stones and rock fragments with weeds, 

 anemones, sponges, and other fixed forms of life attached to them, 

 may be made. The natural appearance of a rock pool is thus more 

 nearly approached, and in a shorter time than if the sedentary life 

 were required to develop on an artificial ground. 



Objection may be raised to the form of aquarium just described 

 on the ground that no life within it is visible except when viewed 

 from above. But is not this also the case with a rock pool on the 

 sea shore ? And has any admirer of nature ever been heard to 

 complain of the beauties of such a pool because he was unable 

 to look at them through the sides ? Further, it may be urged that 

 the inmates of our aquarium will be living under more natural 

 conditions than those of the more popular glass-sided aquaria, 

 because they receive light from above only. 



FIG. 35. CEMENT AQUARIUM WITH A GLASS PLATE IN FRONT 



However, should the reader require a glass front to his cement 

 tank, the matter is easily accomplished. Three sides are built up 

 as before described. A sheet of thick glass plate glass by preference 

 is then cut to the size and shape of the remaining space, and this 

 is fixed by means of cement pressed well against its edges, both 

 inside and outside. 



Water should not be put into the tank until it is quite dry ; and, 

 if one side is made of glass, not until the cement surrounding the 

 edge of the glass has been liberally painted with marine glue, hot 

 pitch, or some other suitable waterproof material. 



If any pipes are required in connection with the water supply 

 of the aquarium, according to either of the suggestions in a later 

 portion of this chapter, such pipes may be fixed in their proper 

 places as the cement sides are being built up. 



The next type of aquarium we have to describe is of low cost 



