164 OUR PUBLIC AQUARIA. 



partly by a water-pressure engine set in motion by 

 the town waterworks, which drives a pair of water- 

 pumps (instead of compressed air, as was done at 

 Paris), and partly by a steam-engine which drives two 

 other pumps." 



Mr. Lloyd's plan of keeping a large underground, 

 dark reservoir for storage purposes, into which the 

 water runs from the tanks after circulating through- 

 out, and from which it starts again on its circulatory 

 round, has been markedly successful. The water is 

 bright and sparkling, and its temperature is thus 

 always easily kept at from fifty to sixty degrees. The 

 aggregate contents of the tanks at the Crystal Palace 

 is only one-fifth of the contents of the reservoir. This 

 readily enables the manager to at once empty any 

 tank into it, should it get wrong, and the slight 

 admixture of the turbid water would be unable to 

 affect the good condition of the general volume. No 

 animals are kept in the reservoir ; the main aeration 

 is produced by the mechanical agitation of circula- 

 tion, and the constant injection of sprays of salt water 

 entangling air into each tank. This is constantly 

 going on, night and day, duplicate steam-engines and 

 boilers being employed, in case of any accident occur- 

 ring to one of them. The stoppage of this me- 

 chanical circulation for some hours is attended by 

 distressing symptoms, and Mr. Lloyd remarks that 

 " the creatures in the tanks, and especially in the 

 taller tanks, must be considered, to some extent, in 



