56 



FRBSH-WATEE AQT7AEIA. 



bradawl, a little larger than the hole in the piping. While 

 being used for this purpose the awl must be steadily turned 

 round and round. The plug (c) can be made of indiarubber, 

 cork, or leather ; and it must be made so that it will close 

 the smaller bore in the pipe perfectly, but not the larger. 

 This plug is kept in position by a pin (d), which should be a 

 black one, run through the centre of the plug, and turned 



-d 



-9 



B 



Fig. «. 



A, Pump for Aerating the Water of an Aquarium ; C and B, Sections of Traps 



which are inserted in A at / and g. 



round another pin, running right through the pipe at e. C 

 and B (Fig. 41) show the section of the trap. The former 

 represents the plug raised for the purpose of allowing the water 

 to be drawn into the pump ; the latter illustrates the plug 

 driven home, and so preventing the water from escaping by 

 the way it entered. Two of these traps ought to be prepared, 



