OR, GLIMPSES BENEATH THE WATERS. 



the oxygen generated in plants is thus clearly an- 

 nounced, and the knowledge of this principle is one 

 of those which have mainly conduced, as I have 

 said, to the successful establishment of Aquaria. 



In the course of his essay Ingenhauss states, 

 still more directly, that plants " immersed in water," 

 when exposed to the action of lights emit an air 

 which he announces as oxygen gas ; and this idea is 

 the key-stone of the Aquarium. 



But, although the discovery of Ingenhauss at 

 once rendered the thing practicable. Aquaria did 

 not then come into fashion. The science of natural 

 history was not at that time sufficiently advanced ; 

 for the specimens, even in public museums, were 

 merely heterogeneous collections, assembled without 

 the slightest regard to classification, or any other 

 useful purpose. A stuffed cat with nine legs, 

 stood, perhaps, next to a bottled snake, followed by 

 the skin of a crocodile, to be succeeded in turn by 

 a very moth-eaten specimen of a King Charles 

 spaniel, supposed, upon good authority, to have 

 belonged to Nell Gwynne." A few scores of such 

 objects, with the addition of an ostrich egg and 

 a few sea-shells, without any attempt at name or 

 description, formed a very respectable museum in 

 those times ; and we may, therefore, easily conceive 



