2 Proceidiiifp. 



by the space available, and other circumstances ; always 

 bearing in mind that the dimensions should be extended in 

 area rather than in depth, a broad, shallow tank being 

 infinitely superior to a narrow and deep one. A depth of 

 twelve inches is amply sufficient for all practical purposes, 

 and has the advantage of being much more readily accessible 

 than one of greater depth. 



Having provided our aquarium the next business will be 

 to stock it ; but first I must say a few words as to its position. 

 This is often more a matter of necessity than of choice : a 

 north or north-east aspect is undoubtedly the best, and such 

 should be chosen wherever practicable. If the only available 

 window face the south or west, much care will be required to 

 protect the aquarium from the direct rays of the sun during 

 the summer and early autumn. In fact, to keep it in health 

 at all in a south aspect during the heat of summer is a very 

 difficult matter indeed. 



The position being decided upon, the next thing will be to 

 procure some fine shingle, — the finer the better, — sufficient 

 to cover the bottom of the aquarium to a depth of a couple 

 of inches. This must be well washed until the water runs 

 away perfectly clear, and then placed in a sieve to drain. 

 Some sort of rock-work is generally desirable. This should 

 be as natural as possible ; fragments of rough granite or 

 ragstone answer well : tufa I have used largely, but am 

 disposed to condemn it, as it is very brittle and apt to make 

 the water thick if disturbed. It has, however, the advantages 

 of being very light, and holding a good deal of water. 



In a tank a good j^lan is to build up the rock-work with 

 Portland cement at each end, either fixed to the slate, or, 

 what is better, in two loose masses, sufficiently strong to 

 bear removal. If cement is used, the rock-work must be 

 soaked in fresh water for two or three weeks to remove the 

 free lime and carbonic acid, or it will poison everything. 

 Having arranged our rock-work and gravel, the next thing 

 required will be the water. This should be obtained a couple 

 of days before it is wanted. It should be dipped from the 

 sea as the tide is flowing, and placed in earthenware vessels 



