CONSTRUCTION 109 



Aquarium Cements. The prime requisites of an aquarium cement 

 are resistance to water, adhesiveness, moderately quick setting without 

 ever becoming stone-hard, and being non-poisonous. A cement combining 

 these qualities is composed of one quart polishing or other fine sand, one 

 quart Plaster of Paris, one pound litharge, two ounces powdered resin, 

 mixed with double boiled linseed oil to a consistency of putty for glazing. 

 This cement has been found to be good for both fresh and marine water 

 aquaria. A durable cement for those who cannot obtain fine sand is 

 made of equal parts by weight of zinc white, whiting and litharge, mixed 

 with double boiled linseed oil to a firm but tacky consistency. 



CONCRETE AQUARIA 



As individual ideas will vary so widely in the design of concrete 

 aquaria, only a few (yet important) directions can be given. Cement 

 should be of the highest grade, fresh and free from lumps. A mixture 

 of one part cement to two of clean, sharp sand is about right. Wooden 

 forms ought to be soaked with water just before using, or else thoroughly 

 paraffined. Cement mixture should be wet enough to just pour, and needs 

 to be well tamped to avoid bubbles. Steel reinforcement rods (^4-inch 

 diameter) are essential, especially around the top edge, where a continuous 

 band should be formed. Through the bottom the bars should be wired 

 together, forming 4-inch squares. Do not be in a hurry to get the forms 

 off. The whole job should be moistened for a day and allowed to stand 

 for two more days if removal of forms is going to cause any strain. 

 Glass must not be embedded directly in the concrete, but provision made 

 for later setting it in with ordinary aquarium cement. If sides do not 

 support the glass evenly they should be cut away or built up until they do. 

 Otherwise glass is sure to crack when the soft aquarium cement yields to 

 the water pressure. After base is finished it is well to paraffine it as 

 described on page 107. All cement pouring should be done at one operation. 



CONSTRUCTION OF WOODEN TANKS 



Many fanciers are of the opinion that for the welfare of fishes there 

 is no receptacle equal to a well-seasoned wooden tank. For breeding 

 purposes they are especially valuable, but in no case should new tanks 

 be used at once. Occasional changes of water for eight weeks make a 

 new wooden tank safe for fish. 



The best wood for tanks is well-seasoned cypress, the natural habitat 

 of the tree being in wet places. Any size tank may be made, but there 

 are two sizes found quite convenient and which cut out of the lumber to 

 good advantage. The larger measures 16 inches high, 30 inches wide 



