54 



FEESH-WATEB AQUARIA. 



and will not split when the leather or American cloth is being 

 nailed to its edge. Fig. 40 will show how such bellows may be 

 made to work with a spring instead of the ordiaary handles. A, 

 the bellows ready for use, to the nozzle of which (j) is attached 

 a prepared indianibber tube (h); B, the lower side, to which 

 the spring (d) is fastened ; C, the upper side, having a round hole 

 (/) not more than ^in. in diameter. To this hole iuside is nailed 

 the usual leather trap-door (i) which opens to receive the air and 

 closes to expel it through the nozzle of the bellows. The nozzle 



Fig. 40. Bellows for Aeeatinq the Water of an Aquarium 



should be about Jin. in diameter, and made of some metal; 

 a piece of small gas-piping will do. It is fixed in the centre of 

 a slip of hard wood, ^in- thick, and this is screwed across the 

 narrow end of B at e. The spring is made by twisting a piece 

 of elastic and stiff wire round the end of a broomstick or some- 

 thing of a like nature, and when made is fastened in the centre 

 of the broad part of B at d. The two sides are joined together 

 by nailing to their edges a piece of leather or American cloth, 



