GLASS RODS AND PIPE'ITES ' 
147 
instead 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. 
The common acids, such as hydrochloric, nitric, sulphuric and 
acetic, in daily use may be kept in small bottles provided with 
pipettes. Fig. 79. 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 
Fig. 79. Reagent Bottle with Fig. 80. Ebonite Tubes for Ammonium 
Barnes Pipette. (X§.) Fluoride. 
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. 80, or in 
cerosine-lined vials. In the latter case frequent renewing of the 
reagent is essential. 
Glass Rods and Pipettes, — The tiny amounts of reagents 
required for microchemical tests are most conveniently removed 
from bottles and vials by means of drawn-out glass rods or 
by platinum wires mounted in a glass handle. The type of glass 
rod found to be most useful is shown in Fig. 81; if one or two 
