120 ELEMENTARY CHEMICAL MICROSCOPY 



of flat mushroom form, thus permitting the removal of stoppers 

 or vials more quickly and easily, and in having all the vials 

 glass stoppered instead of half of them with rubber stoppers. 



FIG. 64. Reagent Set for Microchemical Analysis. (Behrens.) 



The common acids, such as hydrochloric, nitric, sulphuric and 

 acetic, in daily use may be kept in small bottles provided with 

 pipettes, Fig. 65. In similar bottles distilled water, dilute 

 ammonia and dilute glycerine may be placed. A tiny shallow 

 tray will be found convenient for holding the set of liquid reagents. 

 Small bottles holding liquid reagents must frequently be emptied 

 and filled with fresh material, owing to the extraction of soluble 

 constituents from the glass walls of the containers. 



Ammonium fluoride and other fluorine compounds are placed 

 in small stoppered tubes made of hard rubber, Fig. 66, or in 

 cerosine lined vials. In the latter case frequent renewing of the 

 reagent is essential. 



