ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
557 
by plunging them in water, and fitting on a suction-pump to the tube K ; 
the water then flows into the receiver I. When the latter is full the 
tubes B and H are closed by screw-clamps, and air of normal tension 
allowed to enter at K ; the water can run out at M. A sample of water 
Fig. 83. 
can at any time be obtained by clamping the tube H, and fixing on the 
air-pump to the side tube G one of the four test-tubes, and when 
sufficient quantity has flowed into the tube F, the tube B must be 
clamped, and the suction-pump replaced on K. Of course E must 
2 Q 2 
