MANAGEMENT OF THE AQTJABItJM. 55 



cut the desired shape (for which see A). The little nails or 

 upholstering pins are placed very closely together, so that the 

 bellows are made perfectly air-tight; and the indiarubber 

 tubing shoiild be just large enough to fix securely over the 

 end of the nozzle (j). The other end of the tubing must be 

 stopped with a cork, which should be tied firmly in its place. 

 At the cork end of the tubing there are ten or fifteen little holes, 

 which have been made with a strong pin, and so arranged that 

 they are all point upwards when the tubing is at the bottom of 

 the tank, and the bellows are resting upon the stand or table 

 which the aq^uarium is on. "When the instrument is com- 

 pleted and put in the position just described, press the bellows 

 forcibly with one hand, and immediately several small bubbles 

 of air will be seen to rise in the water and ascend to its surface. 

 This contrivance will be found very useful, not only for aerating 

 an aquarium, but also for supplying air to fish which are being 

 taken a long distance by rail or by road. 



rig. 41 represents a useful instrument for aerating the water 

 of an aquarium. It is a small pump or syringe made of india- 

 rubber, and can be bought for a few shillings. It can also be 

 made at home by inserting two pieces of small indiarubber 

 tubing into opposite sides of an indiarubber ball. I have found 

 that sound uncovered tennis-balls wiU answer the purpose. The 

 pieces of tubing, one longer than the other (Fig. 41), are put 

 into holes just large enough to receive them. These holes can 

 be made by means of a hot piece of thick wire. The tubing and 

 the ball are firmly united by covering the junction (Pig. 37, a) 

 of the two several times with pure indiarubber, this having been 

 dissolved in bisulphide of carbon or chloroform. The carbon 

 or chloroform soon evaporates, and leaves the indiarubber dry 

 and firm. A second coat of this solution must not be applied 

 until the first has become hard. At the end of the longer piece 

 of tubing a kind of trap must be fixed, so that the water can 

 be drawn in there, but cannot be expelled by the way it entered. 

 This trap may be made out of about IJin. of lead piping, the 

 diameter of the indiarubber tubing. The bore of one end of 

 the lead piping should be enlarged a little (Fig. 46, B and C). 

 This enlargement can be made with a sharp, square-pointed 



