MANIPULATION OF APPARATUS. 



Much has been written upon general microscopical technique, 

 and some excellent books are easily procured, but it may not be 

 amiss to call the attention of those who are beginning the work 

 with the microscope to a few important precautions and directions 

 that must be observed, and also to offer some few suggestions 

 which may aid in manipulation. 



Access should be had to Prof. S. H. Gage's " Microscopical 

 Methods " which has been freely drawn from in the preparation of 

 the following exercises. 



Interpreting Appearances. 



DIRT OR CLOUDINESS ON THE LENSES. It is important that the 

 lenses be free from dust or dirt, and any cloudiness seen in the 

 field of the microscope should be removed at once. For removing 

 particles of dirt or dust, a camel's hair brush can be used, but for 

 wiping the lenses an old linen cloth or Japanese bibulous paper 

 is to be recommended. To determine the location of the par- 

 ticles of dirt, look into the microscope and revolve the ocular in 

 its place. If the dirt is on the lenses of the ocular, it will revolve 

 in the field of the microscope. If it does not, it is on the objective. 



Should the trouble be with the ocular, remove it from the 

 microscope and wipe its lenses thoroughly. If desired the front 

 lens can be unscrewed and cleaned without injury to the instru- 

 ment. In replacing the ocular, if it fits tightly, observe the pre- 

 cautions given elsewhere to prevent the objective from being run 

 down against the stage of the microscope. If the trouble is not 

 remedied by cleaning the ocular, remove the objective and wipe the 

 front lens being careful not to scratch it. 



