1316 Wisconsin Academy of Sciences, Arts, and Letters. 
ations on the tube b, c, e must be made by discharging water 
into the pan of a fine balance. In this way the 0.5 and 1.0 c.c. 
points can be determined. It will be accurate enough to meas- 
use off the intervening points. At first thought it might be sup¬ 
posed that all that it would be necessary to do would be to put 
a carefully graduated pipette in between b and c, but in practice 
it does not work well because the weight of the fluid in the 
pipette rarities the column of air between a and the mercury at 
e, so that it does not take up quite all that would be indicated. 
SCALE I =• 5 c.m. 
Fig. 5. Pipettometer—detail drawing. 
"When the graduations are once obtained it is then possible to 
measure any fluid very accurately that has practically the same 
specific gravity as the fluid used to make the graduations. 
The chief value of such a piece of apparatus is that in addition 
to preventing the danger of saliva getting into the fluid handled, 
and of handling pathogenic germs, it is economical in that it 
makes possible the use of simple tubes instead of pipettes. These 
tubes can be readily made by even r the unskilled in glass blowing. 
An additional advantage in the use of this apparatus is the fact 
that no error is introduced by the use of pipettes not perfectly 
