24 FEESH-WATER AQUABIA. 



tteir construction is not beyond the powers of an ordinary 

 amateur mechanic. 



The following cements have been found useful in the con- 

 struction of aquaria: 



1. Red and white lead — ^the two being mixed together into 

 a stifE paste. The bed for this cement ought to be painted 

 with gold-size. 



2. One pint each of plaster of Paris, litharge, fine white 

 sand, and one-third pint of finely-powdered resin. This (or in 

 this proportion) should be kept in a well-stoppered bottle, and 

 when wanted the necessary quantity should be made into a 

 putty with boiled oil and driers. This is a very quick-drying 

 cement. It becomes, if anything, too hard. 



3. The same as No. 2, with the exception of the plaster of 

 Paris and the driers. 



4. The best Portland cement. 



5. One part pitch and one-fourth part gutta-percha, applied 

 when warm. These should be melted together in an iron 

 ladle over a gas-flame or lamp. This cement is especially 

 useful for an aquarium made of wood. 



In buying an aquarium, care should be taken to choose one 

 which is broad and shallow in proportion to its size. It 

 ought, at the same time, to be neat in appearance and 

 strongly made. 



The different aquaria suitable for insects only will be de- 

 scribed in another chapter. 



■ j a»«w C ' 



