57 CARE OF APPARATUS. 



instrument may not be injured during the operation. Where a 

 stain or a liquid of any sort is to be applied, place a small drop of 

 it on the slide in contact with the cover. Then hold a bit of 

 blotting paper on the opposite side in contact with the liquid, and 

 the reagent will be drawn through under the cover glass where its 

 action can be observed through the microscope. In case of the 

 action of the acids that may cause effervescence, see that none of 

 the particles of acid fly against the objective or stage of the instru- 

 ment. Do not let any liquid come iu contact with the microscope. 



Always keep the stand free from dust, and when necessary to 

 wipe any part of it rub with the grain of the finish to prevent 

 scratching. 



When necessary to lubricate any of the working parts, use a 

 little soft tallow and wipe the surface slightly to remove any sur- 

 plus oil. 



If any of the parts become loosened by wear, see that the 

 tightening screws are turned. 



In inclining the body of the microscope, grasp the upper por- 

 tion of the pillar and never allow any strain to come on the adjust- 

 ments of the instrument. 



In screwing the objectives in place, use both hands, holding 

 the front of the objective between the first and second fingers of 

 one hand, with the other turn it in place by grasping the milled 

 head OD the back of the objective. In removing it, reverse the 

 operation. 



To remove the ocular or change the length of the draw tube 

 always grasp the course adjustment with one hand to prevent the 

 objective from being forced down upon the stage. 



Keep the lenses in a place where they will not be exposed to 

 sudden changes of temperature, as the expansion or contraction of 

 glass or metal might crack them. 



In getting the object in focus, run the objective down until it 

 is nearly in contact with the cover glass. Then look into the 

 microscope and raise the objective by means of the course adjust- 

 ment, as the image appears in focus, use the fine adjustment for 

 further study. Ahcays focus ^tp, never down. 



