The manometer is the primary basic standard of pressure measurement. It is used in the laboratory to calibrate the Reid
Vapor Pressure gages. To fill the mercury reservoir:
a. Remove the fill plug.
b. Vent the instrument on the low pressure side; assure zero adjustment at midscale.
c. Using a glass funnel, slowly pour the mercury in the unit until the indicating level is at approximately the zero
graduation on the scale.
Mercury is a poisonous material which may enter the body by ingestion, inhalation, or skin
absorption. Mercury has such density, high surface tension, and low viscosity that pouring
without splashing and spilling is almost impossible. When mercury is poured, always use a
funnel and make the transfer over spill trays. If a mercury spill occurs, do not vacuum or sweep
the area. This will disperse mercury throughout the laboratory. Spills may be cleaned up by
using a glass tube of about 6mm diameter drawn out to an opening of about 1mm and connected
by rubber tubing to a filter flask connected with a vacuum pump or aspirator, the flask acting as
a trap. Control of mercury vapor should not be attempted with Flowers of Sulfur as this is not
affective. Spills must be reported to the Environmental Science Officer providing services to the
d. Replace the fill plug tightly.
e. Adjust the scale for the correct zero position in relation to the mercury meniscus.
f. For consistent results in reading the manometer the same way, always read the meniscus at eye level. The
accuracy of the manometer is verified by using a certified master gage. Recommended A-level calibration frequency is
2-32. ANALYTICAL BALANCE.
Figures 2-28 through 2-30 give various views of the analytical balance. The cleaning procedures explained below refer
to these figures.