26 MICROSCOPE AND ACCESSORIES. 



parts put a small quantity of some fine oil, (olive oil and benzin equal 

 parts), on a piece of chamois leather or on the Japanese paper, and rub 

 the parts well, then with a clean dry piece of the chamois or paper wipe 

 off the oil. If the mechanical parts are kept clean in this way a lubri- 

 cator is rarely needed. Where opposed brass surfaces cut, a very slight 

 application of equal parts of beeswax and tallow well melted together 

 serves a good purpose. 



In cleaning lacquered parts, benzin alone answers well, but it should 

 be quickly wiped off with a clean piece of the Japanese paper. Do not 

 use alcohol as it dissolves the lacquer. 



§-72. Care of the Optical Parts. — These must be kept scrupulously 

 clean in order that the best results may be obtained. 



Glass surfaces should never be touched with the fingers, for that will 

 soil them. 



The glass of which the lenses are made is quite soft, consequently it 

 is necessary that only soft, clean cloths or paper be used in wiping them. 



" Paper for Cleaning the Lenses of Objectives arid Oculars. — For the 

 last six years the so-called Japanese filter paper (the bibulous paper 

 often used by dentists when filling teeth), has been used in the labora- 

 tory for cleaning the lenses of oculars and objectives, and especially for 

 removing the fluid used with immersion objectives. Whenever a piece 

 is used once it is thrown away. It has proved more satisfactory than 

 cloth or chamois, because dust and sand are not present ; and from its 

 bibulous character it is very efficient in removing liquid or semi-liquid 

 substances. ' ' 



Dust may be removed with a camel's hair brush, or by wiping with 

 the soft paper. 



Cloudiness may be removed from the glass surfaces by breathing on 

 them, then wiping quickly with a soft cloth or the bibulous paper. 



Cloudiness on the inner surfaces of the ocular lenses may be removed 

 by unscrewing them and wiping as directed above. A high objective 

 should never be taken apart by an inexperienced person. 



If the cloudiness cannot be removed as directed above, moisten one cor- 

 ner of the cloth or paper with 95 per cent, alcohol, wipe the glass first 

 with this, then with the dry cloth or the paper. 



Water may be removed with soft cloth or the paper. 



Glycerin may be removed with cloth or paper saturated with distilled 

 water ; remove the water as above. 



Blood or other albuminous material may be removed while fresh with 

 a moist cloth or paper, the same as glycerin. If the material has dried 

 to the glass, it may be removed more readily by adding a small quan- 

 tity of ammonia to the water in which the cloth is moistened, (water 

 100 cc. , ammonia 1 cc). 



