194 MICROSCOPIC ILLUSTRATIONS. 



largest aquatic live- box, and use the first or third way of 

 mounting. 



The method of using the aquatic live-box is as follows : 

 Take off the lid, applying your finger to the hole in it, or 

 stop it up, pro tempore, with a bit of wax ; then pour 

 in some water to the depth required, and insert your 

 larvae, and apply the inner part to it, observing still to 

 keep the lid undermost : having slid it on far enough to 

 keep the water from escaping, place the box in such a 

 position that the hole in the lid shall point upwards ; then, 

 by squeezing the lid on further (having, of course, first 

 removed your finger orbit of wax from the hole), you 

 may expel all the air, and as much of the water as may 

 be superfluous. It is now fit for use (for the pressure of 

 the atmosphere prevents the water from coming out of 

 the hole) by being placed in the aperture of the stage, 

 and turned one quarter round. A single drop of water, 

 containing animalcules, may be placed between the 

 glasses of the smaller boxes ; and, if the tubes are made 

 air-tight by a little grease, and the hole stopped up, may 

 be kept for weeks together without evaporating. 



If very delicate and exceedingly transparent animal- 

 cules are to be examined, use the adapter (fig. 28), with 

 the smallest aquatic live-box mounted upon it, and se- 

 cured by the bayonet-catch : let it be placed between the 

 connecting cross-bars, 'u 'u, and the superior plate of the 

 slider-holder, which arrangement permits the adapter 

 to be moved about: screw the wheel of diaphragms 

 (fig. 24) on to the bottom of the slider- holder, and see 



