22 



T. C. WHITE ON THE AQUARIUM 



placed. This should not fit too accurately round its edges, so that 

 if necessity requires its removal, no difficulty may be experienced 

 in doing so. The object of this inclining false bottom is worthy 

 of being borne in mind, as it is of some importance. It affords, in 

 the first place, a varying depth of water, enabling your animals to 

 select the depth most suited to them, and secondly, it divides the 

 tank into two compartments, that under it being filled with water 

 which is always cool and in a state of rest, while that above it is 

 exposed to the light, and actively engaged in ministering to the 

 animal and vegetable life growing in it, and a compensating action 

 takes place between these two compartments which very materially 

 aids in keeping the water in a wholesome and healthy condition. The 

 great object to be kept in mind in working an Aquarium is to assimi- 

 late its conditions as much as possible to those of natural rock pools. 

 All attempts to construct grottoes, arches, or temples, or, in short, 

 any such like ornamentation, are to be strongly deprecated ; but 

 sandstone rockwork, roughly disposed, is of much use, affording 

 shelter for your stock, and, by extending the superficial area of 

 the bottom, increasing the aerating capacity of the vegetation, 

 which will ultimately clothe it. This rock may be cemented on 

 the sloping bottom with Portland cement, but none must be placed 

 on the sides of the tank, as that would interfere with the removal 

 of the false bottom, should that be required. Care must then be 

 taken to thoroughly soak the rockwork and cement for a fortnight, 

 or even longer, frequently changing the water, that all the soluble 

 matters may be removed from them. When you feel sure that 

 these are sufficiently soaked, and that no more lime will be 

 eliminated from the cement, you may move on a step further. 

 While some forms of animal life cling to the rocks, others will 

 burrow in the sand, therefore a supply of this must be added. If 

 you are not in a position to get sea sand, an excellent substitute 

 may be found in the silver sand sold at any of the oil shops, and 

 for an Aquarium the size of mine, two gallons will not be too great 

 a quantity. This must be repeatedly washed till the water is quite 

 clear when the sand is stirred up in it, and then it may be placed 

 in the tank. Everything being now ready for the sea water, this 

 brings me to the second division of my subject. The water 

 employed may be artificial or natural sea water. Of course, where 

 attainable, the preference is to be given to real sea water, because 

 however closely its composition may be imitated in these days of 



