42 HOUSE, GARDEN, AND FIELD 



for a few hardy ones. But if you wish to make the most 

 of the aquarium, you must construct it on a larger scale. 

 I have kept one which measures 4 ft. long, 18 in. wide 

 and 16 in. deep, for twenty years, and have found it so 

 profitable that I strongly recommend such an one to 

 others. The large space, abundant light and simple 

 furnishing of the laboratory or schoolroom are taken for 

 granted. The parlour aquarium must be on a compara- 

 tively small scale, and I doubt whether it will succeed 

 anything like so well for general purposes. 



First as to construction. My aquarium was strongly 

 framed of deal, and stands on a stout table made for the 

 purpose ; no slate enters into it. The floor, ends and 

 one of the long sides (that facing the window) were of 

 wood, and only one side is of glass. Opposite the windows, 

 I should explain, is a good roof -light. The ends of the 

 aquarium were bolted together by four strong iron rods, 

 two at the top and two at the bottom, which were passed 

 through thick battens, and well secured by nuts. The 

 rods run along the tops and bottoms of the long sides, 

 and the ends project sideways two inches beyond them. 

 All wood that had to resist wetting was covered half an 

 inch thick with a mixture of sand, mastic and red lead, 

 laid on with great care and thoroughly hardened before 

 exposure to water ; no leak has ever showed itself. A 

 water supply- tap and a waste-pipe were provided, but the 

 water is hardly ever changed. At the bottom a thick 

 layer of fine mud, mixed with a little powdered chalk and 

 calcium phosphate, was laid down. The side next to the 

 window was darkened to prevent too abundant growth 

 of green algae ; if this side has been made of glass, it 

 should be covered with paint, but there should be an 

 ample supply of diffused light. A loose cover of per- 

 forated zinc is used to keep out dust, but is often dis- 

 pensed with to favour surface-growths. 



In this aquarium I have grown a variety of plants. 

 Isoetes, the water Lobelia, Frog-bit, Myriophyllum, pond- 



