CHAPTER IV 



HOW TO USE THE MICROSCOPE 



In beginning work with the compound microscope, place 

 the base of the microscope opposite your right shoulder, if you 

 are right-handed; or opposite your left shoulder, if you are left- 

 handed. Incline the body so that the ocular is on a level with 

 your eye, if necessary; but if not, work with the body of the 

 microscope in an erect position. In viewing the specimen, keep 

 both eyes open. Use one eye for observation and the other 

 for sketching. In this way it will not be necessary to remove 

 the observation eye from the ocular unless it be to complete 

 the details of a sketch. 



Learn to use both eyes. Most workers, however, accustom 

 themselves to using one eye; when they are sketching, they use 

 both eyes, although it is not necessary to do so. 



Open the iris diaphragm, and incline the mirror so that 

 white light is reflected on the Abb6 condenser. Place the slide 

 on the centre of the stage, and if the slide contains a section 

 of a plant, move the slide so as to place this specimen over the 

 centre of the Abbe condenser. Then lower the body by means 

 of the coarse adjustment until the low-power object, which 

 should always be in position when work is begun, is within one- 

 fourth of an inch of the stage. Then raise the body by means 

 of the coarse adjustment until the object, or objects, in case a 

 powder is being examined, is seen. Open and close the iris 

 diaphragm, finally adjusting the opening so that the best pos- 

 sible illumination is obtained for bringing out clearly the struc- 

 ture of the object or objects viewed. Then regulate the focus 

 by moving the body up or down by turning the fine adjustment. 

 When studying cross-sections or large particles of powders, it 

 is sometimes desirable .to make low-power sketches of the speci- 

 men. In most cases, however, only sufficient time should be 

 spent in studying the specimen to give an idea of the size, struc- 



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