what was an olijeet of beauty and admiration would become in a few short liours loathsome and 

 foul. The same "eifect would occur, on a larger scale, in tlie ocean itself, were it not for the storms 

 and tempests that cause the surface of the sea to be dashed into waves aud billows and sweetened 

 and revivified by the life-giving oxygen of the atmosphere. 



The Tanks. 



The two tanks whicli are situated in the eastern corridor are constructed of Oastlemaine 

 slate slabs — a material, however, which lias not been found suitable, as the chemical action of 

 the sea-wator after a time causes exfoliations and consequent leaks — and it has been found 



necessary to have these tanks faced witli 

 l)ricks. The slate is, however, excellently 

 adapted for smaller tanks (such as those 

 which are found in the entrance vestibule, 

 lictween which and the Fernery may be seen 

 :i tank entirely constructed of iron and glass, 

 I he liottom being plate iron, riveted together, 

 rhc jiillars of T iron being covered by cast- 

 iron columns). The 60-ft. tank in the fur- 

 ther corridor is also constructed of iron, 

 hut on a (liiferont principle, the bottom con- 

 sisting of cast-iron plates, riveted together. 

 The glass is liest jdate, I5 inches thick, and 

 is tixed in ])]ace with a mixture of red and 

 white lead, with the addition of a little oil 

 or Russian tallow, to ])revent it setting too 

 hard. 



The liglitingof the tanks is all done from 

 aliove, and a certain degree of sombreness is 

 maintained in the corridors in order to allow 

 of tlie hal)its of the denizens of the tanks 

 being properly observed. The space where 

 the sjiectators stand is opaque to the tishes 

 themselves, as can be easily demonstrated 

 by passing the liand close to the glass, when 

 it wdl lie seen that no notice is taken Ijy the 

 nioxenient, even though the eye of tlie tish 

 lie within a few inches ; but the slightest 

 sound of a tap on the glass by a finger 

 iilitains instant attention. A curious effect 

 ran also be observed liy glancing at the nji])er 

 Va.ctiun, gives ii, mirrored rppresentatimi oC tlie interior 



li\ re 



surface of the water, wjiicli, acting 

 of the tank and its contents. 



The Watek. 



The water which is used in the tanks is, in the first instance, obtained from the Bay, 

 and pumped into 4U0-gallon tanks on carts, and then allowed to nm into three nnderground 

 reservoirs containing in the aggregate over 100,000 gallons ; thence it is pumped into the tanks 

 and allowed to return to the reservoirs. At the first ini'cption of the Acpiarium tliere was a great 

 difficulty in getting the water free from tnrliidity, and it was some consiileralile time before 

 experience tauglit that the cause was insufficient circulation and aeration, togetlicr with an excess 

 of light; rays of the sun with their all-vivifying power start into life tountless millions of 

 infusorial spores which cause the water to assume the appearance which is technically known 

 as " pea soupy," and it becomes necessary to run the water oft' into one of the underground 

 reservoir tanks, where in utter darkness the microscopic growths cease to exist and in three or 



