THE AQUARIUM, 689 



which quickly develop microscopic vegetation or confervm upon the 

 sides of the aquarium, and upon the rocks within it. This vegetation, 

 although unobtrusive, performs all the work done by the more con- 

 spicuous plants of the fresh- water aquarium. The credit of inventing 

 the aquarium proper has generally been given to Madame Power, 

 before alluded to, who, in the year 1832 and thereabouts, while study- 

 ing the marine animals on the coast of Sicily, brought into use the 

 " water-cage " to facilitate her investigations. But Mr. W. Alford 

 Lloyd, the present Curator of the Crystal Palace Aquarium, London, 

 who is one of the highest authorities on the subject, contradicts that 

 view. In an article published in Science Gossip^ several years ago, 

 he says that the introduction into the " water-cage " of " plants for 

 the avowed purpose stated heforehand^ of preserving the purity of the 

 sea-water, and of sustaining the animals in health, is due to Mrs. 

 Thynne, who experimented in London, in 1846, on living madrepores." 

 Madame Power, it appears, was in the habit of changing the water in 

 her cages. It would seem, therefore, that while to Madame Power 

 belongs the credit of furnishing the clew to the scientific value of the 

 aquarium, to Mrs. Thynne belongs that of inventing the aquarium 

 itself. 



Some interesting facts, not wholly of a zoological nature, have 

 been observed through the aquarium. Thus it was ascertained that 

 objects through the medium of water appear shorter than they really 

 are. At the distance of a few feet, a fish, or other object, apj)ears 

 about one-fifth shorter than it is. Mr. Lloyd, through Science Gossip, 

 has made known some curious efiects of electricity on fish. A friend 

 of his had a large fresh-water garden-aquarium. One day, during a 

 thunder-storm, a house, about 200 feet from the aquarium, was struck 

 by lightning. At the moment of the flash, all the fish in the aquarium, 

 forty-three in number, of various kinds, were suddenly suspended per- 

 pendicularly, heads downward, with their tails at the surface of the 

 water, in which position they feebly and vainly endeavored to swim 

 to the bottom of the tank. " The manner in which the eels were 

 almost jerked out of their hiding-places, in the sand at the bottom of 

 the tank, was very remarkable. In less than half an hour forty-one 

 were dead, strongly curved, almost in the form of semicircles, and fast 

 decomposing ; but two gradually recovered, by being placed in run- 

 ning water. It is well known that when fish become sick and die, 

 under ordinary circumstances, they turn belly upward, horizontally, 

 instead of having nose downward, as in this case." 



These facts sufficiently indicate the utility of the aquarium, and 

 the necessity for having one at Central Park. As an indication of the 

 interest commanded by the subject in England, it may be mentioned 

 that Mr. Kent has begun a series of lectures at Manchester, to show 

 ,.ow it subserves the purposes of scientific instruction. The first lect- 

 ure was delivered on the last Friday in June to a fairly numerous 



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