THE MICROSCOPE 45 



nificant details. A regular order of procedure should 

 be observed and should be so well in mind that it 

 becomes more or less automatic. In this way the 

 worker is free to devote greater attention to the 

 examination of the specimen and less to the mechan- 

 ical details of focusing and lighting. 



Position of Microscope and Worker. The work- 

 ing tables in a laboratory should be so arranged that 

 the students can secure light from windows facing 

 north. North light is preferred because it is less 

 subject to variation. The instrument should be 

 placed' opposite the left shoulder and not more than 

 four inches from the edge of the table. This permits 

 one to use the right hand for drawing and the left for 

 focusing or other adjustments. If one is left handed, 

 the microscope should be placed opposite the right 

 shoulder. Shifting the microscope further than a few 

 inches from the edge of the table not only cuts off 

 the light from the other students in the row, but 

 necessitates an uncomfortable working position. 

 Although it may be necessary to incline the instru- 

 ment, better results will usually be obtained by keep- 

 ing it upright. If working with temporary mounts, 

 one must keep the microscope upright to avoid loss 

 of the specimen. In any case the inclination should 

 not be more than 45 degrees. If the student finds 

 that when he sits upright his eye is below the level 

 of the ocular, he should incline the instrument. When 

 a microscope is carried, it should be kept upright, 

 two or three fingers grasping the pillar below the 

 stage. Otherwise the fine adjustment may be injured 

 or the ocular lost. 



Lighting. After placing the microsqope in working 



