the station. There is no way to remedy the defect. Return the barome-
ter to the depot and requisition a new one.
(4) For the first few months after the aneroid is built, the drift
effects are more pronounced, but after this time they usually become
negligible. In general, the longer the barometer is in use, the more
consistent the performance is likely to be.
(5) Occasionally a barometer will show a persistent drift. TO detect
this condition, keep a record of the amount of resetting necessary to
eliminate drift. If, over a period of time, this total exceeds 12 millibars,
requisition a new barometer and return the defective instrument to
16. BAROMETER ML-102B (fig.
7) . a. The
mechanism of Barometer
M L -102 -B is built within a brass frame. While differing considerably
in internal appearance, this barometer functions practically the same
a s Barometers ML- 1 0 2-E and ML-1 0 2-F, except for an additional
step in magnification.
b. In Barometer ML-102 -B the atmospheric pressure acts upon two
sets of cells. The movement of one group (of two cells) is transmitted
to the center of the main lever. The movement of the other group (of
three cells) is transmitted to one end of the main lever. Thus the
initial magnification is performed by a simple lever in which one end
and the center are moved oppositely by the two sets of cells. This causes