CEMENT AQUARIA 



G. E. STONE 

 Massachusetts Agricultural College, Amherst, Mass. 



No botanical laboratory is properly equipped without some 

 place in which to grow aquatic plants, mosses, liverworts, etc.; 

 and to grow them successfully in winter it is very important to 

 have the proper conditions, both as regards the temperature of 

 the water and air, and sunhght to keep the plants in a healthy 

 condition. For instance, it is always very difficult to carry Chara 

 and Nitella over winter, and the best method we have seen 

 consists in keeping the plants where the temperature of the air 

 and water is very constant and there is not too much light. 

 Too sudden changes in the temperature of the water must be 

 prevented, for nothing is more injurious to aquatic plants than 

 allowing the water to become too warm or too cold. For some 

 plants the balanced aquarium, in which plants and animals are 

 grown together, is best. 



The writer has had many years' experience with aquaria for 

 plants to be used in the laboratory, and a few fish for pets. 

 Large glass jars, either square, rectangular or round, have proved 

 very unsatisfactory; they are so easily broken, especially if sand 

 is placed in the bottom. Besides, the small volume of water 

 is easily influenced b}' temperatures, and this is disastrous to 

 the growth of aquatic plants. Even the large, iron aquaria, with 

 a capacity of 25 to 30 gallons, are unsatisfactorj^ in some waj's, 

 and are also ver^^ expensive. 



In the construction of the botanical laboratorj^ — Clark Hall — 

 at the Massachusetts Agricultural College several years ago, con- 

 siderable space was left in the small greenhouse connected with 

 the building for aquaria, and a place to grow mosses, liverworts, 

 etc. We felt sure that the unsatisfactor}- and expensive iron 

 and glass aquaria which seemed to be the onh' things available 



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