ADJUSTMENT OF MICROSCOPE 17 



11. Before putting a slide aside ~be careful to label it, 

 writing at once on an adhesive label the name of the 

 plant, part, direction of section, and medium in which it 

 is mounted. 



B. Adjustment of the Microscope for Work. 



Before beginning work it should be ascertained that 

 the microscope is in good working order: if it be a 

 stand without rackwork, see that the stage of the 

 microscope is clean, and that the tube moves easily and 

 smoothly ; if not, take out the tube, and rub it with a 

 clean cloth ; if still stiff, apply a very little mineral oil 

 or vaseline, and rub with a clean cloth till there is no 

 appearance of oil on the tube : it should then work 

 freely. Nothing causes a greater strain on a microscope 

 than neglect of this simple point. 



Next see that the lenses are clean ; to this end first 

 dust the mirror, and adjust it so as to reflect light 

 through the instrument : insert first one eye-piece, then 

 the other : rotate each eye-piece, and if any specks be 

 seen to rotate with it they are on the lenses of the eye- 

 piece, and must be removed with a soft chamois leather, 

 or a fine linen or silk cloth (old pocket-handkerchief). 

 Carefully examine the front lens of each objective, and 

 if any dirt be seen wipe the lens gently with a chamois 

 leather, or fine linen or silk cloth. Glycerine is apt to 

 gain access to the objective in careless hands ; when this 

 is the case the lens is to be washed with a jet of distilled 

 water, and carefully dried. Since the lenses are often 

 fixed with balsam, great care must be taken that the lens 



C 



