THE NEW YORK AQUARIUM. 409 



a I Hint in the tanks. Now they are a dirty brown, now they change 

 to alternating blotches of black and white, and presto, they are pure 

 white. The Eed-snappers and Yellow-tails change in the twinkling 

 of an eye so as to be almost unrecognizable. Nearly all these fishes 

 may emit flashes of light apparently at will. 



The Cow-fish and its relative the Trunk-fish always excite the 

 interest of the visitors, who are amused at their triangular, box-like 

 bodies and odd manoeuvres. Equally attractive are the Morays, of 

 which two varieties are shown; the beautiful Speckled Moray and the 

 great Green Moray. The specimens of the latter now in the Aquarium 

 measure, respectively, seven and one-half feet and six feet long. 



The collection of coastwise fishes is excellent, and it contains many 

 rare and little-known varieties, such as the weird Moon-fish, the Spade- 

 fish, the Crevalle, the Orange file-fish and the Barracuda, as well as 

 the common food fishes of the markets. 



The first requisite of an Aquarium is water, and, while very small 

 aquaria may be, and are, successfully maintained without changing 

 the water, by the use of plants to supply oxygen, this system would 

 not answer at all for large tanks. In England and on the Continent 

 many of the large aquaria store great quantities of water, both fresh 

 and salt, in dark reservoirs, and use it over and over again, filtering 

 and aerating it each time. 



In the New York Aquarium this system is not used. Fresh and 

 salt water are supplied to the tanks but once and carried away to the 

 sewer. The fresh water is furnished from the city water mains. The 

 salt-water supply was originally taken direct from the harbor, but, 

 while digging in the cellar to lay a foundation, the workmen pierced 

 a layer of hardpan clay, and water rushed into the excavation. Pump- 

 ing did not lower it, and tasting proved it to be salt. It was at once 

 utilized as a source of supply and proves to be excellent. The layer of 

 tsand underneath the clay is an immense filter bed that removes all sus- 

 pended matter and furnishes clear, limpid water in unlimited quantity. 



Both kinds of water are pumped into large reservoirs and flow 

 thence by gravity to the tanks. Some of the piping is gutta-percha, 

 but practice has demonstrated that first-quality galvanized iron pipe 

 is entirely satisfactory, and it is largely used. Between the reservoirs 

 and the tanks are devices for regulating the temperature, and these 

 are necessitated by the extreme diversity of the collection. 



In the summer, the fresh water supplied to the salmon family must 

 be kept down to 55° F., while in winter the tropical salt-water fishes 

 demand 70° F. The former is maintained by an ordinary refrigerating 

 machine, the latter by utilizing the waste steam from the radiators 

 ;and the pumps. 



The exhibition tank, like much of the plant, is the outgrowth of 



