APPENDIX A
The formula to be used in obtaining the density is:

309

WQ WQ

where w' = weight of liquid at t°C,
WQ = weight of water at fC,
po = density of water at £°C.
The liquid is introduced or removed from the pycnometer by

I P

\ i|:J

!' ! ' ' '

I IwK

ii !!vif

TOSUC7JON

FIG. 95.—Apparatus for cleaning and filling viscometer.
means of the capillary pipette, used also for introducing liquid
into the viscometer, shown in Fig. 95.
This rubber tubing as well as the heavy walled tubing at the
top of the viscometer should be scrupulously cleaned on the
inside to remove dust before they are used.
If the capillary stem of a 25 ml pycnometer has a bore of 0.08
cm it is capable of an accuracy of 0.01 per cent by reading the
meniscus to within 1 mm. It is well to have two pycnometers