Hints Regarding the Care of the Microscope 121 



HINTS REGARDING THE CARE OF THE 

 MICROSCOPE. 



Cleanliness is a most important feature in microscopical 

 work. Never allow dust to accumulate upon the micro- 

 scope, for it soon finds its way between the fittings, and 

 causes mechanical screws to work with backlash. When 

 not in use, the instrument should always be placed in its 

 case or under a glass shade. 



Dusting. — For dusting the microscope, a camel-hair 

 brush should be used in the first place ; by the aid of this, 

 dust can be removed from niches and crevices with great 

 ease. For wiping over the stand, also for cleaning eyepiece 

 lenses, the fronts of objectives, and other optical work, the 

 writer has always employed handkerchiefs that are made of 

 ^ mixture of silk and cotton. These should be washed out 

 two or three times until they are soft and free from dust. 



Adjusting a Microscope. — It is not to be recommended 

 that other than microscope makers should take the instru- 

 ments to pieces ; but it is often necessary, where a person 

 resides abroad, that 'he should be able to adjust his own 

 microscope. It is difficult to give definite advice, because 

 the fittings vary considerably in every make of microscope. 

 If the rack-work of the coarse adjustment or sub-stage 

 develop loss of time, it is more often than not due to the 

 bearings clutching on account of the presence of dust, or to 

 their becoming dry. The way to adjust them is as follows: 

 Eack the body up as far as it will go, and mark lines with 

 a pen and ink on the pinion stem and the body of the 

 microscope to correspond with one another. The object of 

 this is to ensure the replacement of the body so that the 

 rack engages the correct leaf of the pinion, and it is here 

 presumed that a Jackson model microscope is used, and 

 that it has a stop-pin to the rack, which prevents the body 

 being removed from its fitting. Now remove the cock- 

 piece, which holds the pinion in position, and take away 



