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THE POPULAR SCIENCE MONTHLY 



The cold salt water is pumped through the extensive cast-iron radia- 

 tors of the different cold rooms and the temperature regulators auto- 

 matically open or shut the valve at the inflow of the cold salt water. 



For many years it has been demonstrated, notably in the great 

 Berlin aquarium, that marine animals and plants may be transported 

 a long distance from their native habitats and then live on in aquaria 

 with unimpaired health and growth. Hence it became an essential part 

 of the plan to include marine organisms within the field of work of the 

 institution and a complete equipment was installed for the investiga- 

 tion of problems of marine biology. Natural sea water, from the zo- 



A B 



Fio. 14. A. Carbonic-acid Cooling Machine with condenser, pumps for the 

 compression of carbonic acid gas and for the circulation of the cooled salt water. 



B. One of the Cold Rooms with the cast-iron radiators for the circulation of 

 the cold salt water. 



ological station in Triest, is brought in car loads of thirty casks, each 

 containing 500 liters. It is not difficult to maintain the proper con- 

 centration of salts and the same water can be used for years. It is not 

 more expensive than artificial sea water, which is apt to vary in its con- 

 stitution. Non-corrosive substances like glass, porcelain, glazed clay, 

 cement, wood, hard rubber and lead lined with tin, were used in the 

 construction of the aquaria for sea water. A plan of these aquaria, 

 with the associated apparatus for aeration (Fig. 15), shows the distri- 

 bution of sea water from the elevated reservoir (A), to cement basins 

 (D), or to the smaller isolation jars in the next compartment. The 

 effluent water, after being cleansed by running through the filter (H), 

 is stored in the subterranean cistern {K), and thence driven by the 



