. Madden : Aquaeia. 23 



And as Naturalists we can but look at tlie establishment of Aquaria 

 tbroughout this country as one of the great events of this age. 

 Natural History cannot succeed as it ought to succeed, without 

 multiplied observers, and to multiply observers it must be popularised. 

 This is what I believe Aquaria will tend to do ; and one cannot 

 but hope that when our mechanics and artizans visit the sea shore, 

 they may with observing eyes note the lovely forms of life that there 

 abound, and thus gain knowledge and a love for nature, which will 

 do more to invigorate the system and strengthen the body than sitting 

 about on the public piers, smoking cheap cigars and drinking beer. 



Aquaria are in a limited sense things of antiquity, for I doubt not 

 school boys long ago used to do what they do now, keep in bottles, 

 or jars, or any other receptacle procurable, tadpoles, newts, eels, 

 minnows, gudgeon, &c., until having tired of their pets, they forgot 

 them for a few days, and they perished. 



But Aquaria as we now think of them assume nobler proportions — 

 that of Brighton has 740 feet of linear frontage — Manchester (the one 

 I visited) 680. The word " Aquarium " was introduced by P. H. 

 Gosse, 1853, and has been retained ever since ; although he limited 

 it to a place where such animals and plants were kept which could not 

 live out of the water for any length of time. Now porpoises and seals 

 are justly considered as having a place among the inhabitants of an 

 aquarium. 



The great difficulty in an aquarium is how to keep the salt water 

 thoroughly dear sindL fresh, especially when we think of the distance 

 of Manchester from the sea, and the expense in carrying barrels of sea 

 water backwards and forwards. 



There are two systems, both of which have their advocates ; they 

 are represented by Brighton and Manchester, Brighton being on 

 the "Aeration" system, and Manchester on the "Circulation" 

 system. In the Aeration system the water is practically stagnant in 

 the tanks, but air is forced by means of steam power into the bottom 

 of the tanks, and from thence it rises in large bubbles to the top. 

 The water in this aquarium used to be supplied from the sea, but it 

 was found that this often rendered the tanks turbid and muddy, and 

 has now been given up. The objections to this system are : 



1. The water is never very clear. 



2. The number of fish in each tank must be limited. 



3. The water in a well-stocked tank must be occasionally changed. 

 In Manchester the circulation principle is in use. There are 



300,000 gallons of sea water in the tanks and reservoirs — about 



