22 MICROSCOPY FOR BEGINNERS. 



field of view, it must actually be pulled towards the ob- 

 server's right hand ; and if the image is to travel up the 

 field, that is, away from the observer as he sits at the 

 microscope, the object must really be slipped towards 

 him, because the lenses reverse the image. This seems a 

 very complicated proceeding, but it soon becomes the 

 easiest thing imaginable. At the first trial the object 

 will be sure to leap entirely out of the field, because it 

 will be too rapidly moved, and the motion is magnified 

 as well as the object ; but the student will become so 

 expert that before very long he will be able to make 

 on the stage of his microscope complicated dissections 

 with fine needles of the internal organs of the house- 

 fly, or some other equally small insect. 



The stage will probably have two springs on the up- 

 per surface, one on each side. These "spring clips" 

 are to keep the glass slide holding the object in position, 

 unless intentionally moved. The slide is put under the 

 clips, and the object, provided it is itself stationary, will 

 remain in the field, where it can be examined quietly 

 and comfortably. 



The diaphragm should always be present. It will be 

 pierced near the edge with a series of openings of vari- 

 ous sizes, to modify the amount of light thrown on the 

 object, the largest opening admitting the greatest 

 amount. The beginner will at first be disposed to use 

 too much light ; indeed this is a fault of many older mi- 

 croscopists. More can be seen with a moderately light- 

 ed field than when the eye is dazzled and half blinded 



