PREPAEING THE TANK. 33 



poses, where we intend to grow the floating plants, as 

 ccratop/njlum, chara, calatrichc, etc. 



The amateur naturalist must, however, trust, in a great 

 part to what he will acquire during his own experience 

 to <niide him in his after attempts : and must not be dis- 

 couraged if he fail once or twice, for it will be a wonder 

 if he succeed on the first trial. He may get many inva- 

 luable hints from books, but cannot .always be governed by 

 what his author has given him, for instances may occur 

 which the writer has not taken into consideration, ami, then, 

 what is the neophyte to do ? lie must, as I said before, 

 be "-overned by his own experience : for, do we not find 

 that Mr. Gosse condemns red sand and silver-sand as cer- 

 tain to stain the water ? whilst Mr. Ilibberd, on the con- 

 trary, observes : " I have two tanks now at work, both 

 bottomed with such material" (red sand and silver-sand) 

 " and the water preserves a crystalline brightness. I have 

 also a marine tank, in which the bed is formed of common 

 silver-sand and garden pebbles ; it has been in use nine 

 months, with no unfavorable results." Thus Mr. Hibbcrd 

 and I have used silver-sand, and it has succeeded ; and 

 yet I have also used it, and it has failed from some un- 

 lookcd for and unknown reason. All I can, therefore, do 

 is to give my readers the result of my experience in this 

 branch of the subject, and leave it to them to experiment 

 for themselves. I have heard of, though I have never 

 seen, the bottom of a fresh-water tank entirely composed 

 of marine shells and pieces of coral. These, of course, are 

 extremely unsightly, although in a marine tank they arc 

 proper enough, if they arc arranged tastily ; though I must 

 confess to one weakness, and that is, that I have been so 



