TO THE STUDENT 7 



they occur in the note-book, with the page number 

 near the right-hand edge, and a neat dotted line 

 extending from the subject to the page number. 

 F. The Microscope: 



21. Full directions for the use and care of the compound 

 microscope will be given by the instructor. The 

 student should clearly realize from the first that the 

 science does not reside in the instrument. The latter 

 is merely an aid to the eyes, but not to the mind, 

 and is made necessary by the limited range of our 

 unaided vision. It should be used only after one has 

 seen all that he possibly can with the unaided eye. 



22. The following points should be constantly borne 

 in mind: 



(a) Keep all parts of the instrument, especially 

 the lenses, scrupulously clean. 



(b) Never attempt to take the instrument apart. 



(c) Never remove lenses from the stand. If it 

 is ever absolutely necessary to do so, then 



(d) Never lay a lens down on the table. 



(e) Never touch the lens with the fingers or eyelids. 

 (/) Never try to clean the lens with the handkerchief 



or anything except lens paper, 

 (g) Never examine any object without covering 



it with a cover-glass. 



(h) Never allow the objective to touch the cover- 

 glass. 

 (i) Never focus down while looking through the 



microscope, 

 (k) Be sure that the slides and covers are absolutely 



clean. Dirt will be magnified as well as the 



object you are studying. 

 (/) Handle all slides and cover-glasses by the edge, 



never touching their surface with the fingers. 



