THE AQUARIUM. 6) 



of oxygen created in water, and the quantity con- 

 sumed by aquatic animals. And it became equally 

 necessary to know the means by which that supply 

 was continually generated. Without the knowledge 

 of these facts, and the principles by which they are 

 regulated, it would have been impossible to establish 

 euch a marine aquarium as we may now any day 

 examine in the Regent's Park (London) ; where, in 

 a few glass tanks, of very moderate size, we may see 

 examples of some of the most curious forms of animal 

 and vegetable life peculiar to the depths of the ocean ; 

 forms so singular, that their first exhibition created a 

 sense of wonder little less intense than that which 

 must have been caused, long years ago, by the first 

 public display of the mountain form of the Elephant 

 to the people of cold northern countries. 



" Those principles, the knowledge of which was 

 requisite to enable us thus to view the wonders of 

 the Ocean in their living state in the aquarium, were 

 not mastered at once, or by one man, or in one gene- 

 ration. The nature of certain relations between 

 animal and vegetable life, upon which they are 

 founded, was first advanced by Priestley, towards the 

 close of the last century, who proved that plants give 

 forth the oxygen necessary to animal life. 



" But it was not till the year 1833, that Professor 

 Daubeny communicated to the British Association at 

 Cambridge, a paper concerning some new researches 

 prosecuted in the same direction ; while in the sum- 

 mer of 1850, R. Warrington communicated to the 

 Chemical Society a series of observations on the 

 6 



