28 



THE STKUCTURE OF 



direct light of the sun, in which to place a small, 

 firm, steady table. On this the Microscope should 



be placed, and the object- 



glass should be screwed on 

 to the tube. The mirror 

 should be then adjusted so 

 as to throw a bright ray of 

 light on to the object-glass. 

 The eye-piece having been 

 previously placed at the top 

 of the tube, the Microscope 

 is now ready to receive a 

 transparent object. If the 

 object to be examined is an 

 animalcule, it may be con- 

 veyed to the animalcule-cage 

 by means of a glass tube, 

 called a pipette or dipping- 

 tube (fig. 12), which should 

 be dipped into the water 

 where the object is con- 

 tained, with the finger 

 I covered over the upper orifice, 



so that no air can escape. 

 By taking the finger off 

 n when the tube is in the 



water, the fluid will rush 

 into the tube, and with it 

 the object to be examined. 

 The finger is again applied 



Fig. 12. Dipping Tubes. to tne to P f tne tube > and 

 the fluid obtained conveyed 



to the animalcule-cage. Only such a quantity of 

 the water should be allowed to fall out of the 

 tube on to the cage as will enable the observer 

 to put on the cover of the cage without pressing; 



