THE AQUARIUJ\\. 



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CHAPTER 1. 



GENERAL PRINCIPLES. 



OUARIA, properly so-called, have a history ex- 

 tending back no further than forty years. True, 

 as long ago as 1790, Sir John Dalyell had a 

 collection of living marine animals in various tanks and 

 glass jars, which he maintained at the cost of consider- 

 able labour ; for, under his method, it was necessary for 

 him to hire men to bring him up daily supplies of sea 

 water in order to maintain life in his jars. His plan was 

 to change the water every day — often twice a-day — by 

 drawing off that contained in the jars and replenishing 

 them by the daily supplies from the sea. Though this 

 was, undoubtedly, the progenitor of the aquarium, yet it 

 could hardly be considered as aquarium-keeping in the 

 modern meaning of the term ; for the principles which 

 should guide all in the management of aquaria were 

 ignored, or perhaps it would be more correct to say 

 7inknozvn. For an aquarium should be established and 

 maintained on natural laws and principles, and to know 

 what these are we cannot do better than observe the life 



