RELEASE AND RECORDER RECORD B4- 43 
a. To facilitate the computation of drift corrections, 90 may be 
used as the divisor if the low-reference drift is to the left 
and is 3.0 or more but not more than 7.0 ordinates. If the 
drift is to the right, in the same amount, 100 may be used as 
the divisor. 
b. When the drift exceeds seven ordinates, it is essential that 
the actual value of the low-reference drift line be used as the 
divisor. 
c. If the reference drift is less than 3.0 ordinates, correction 
charts based on 95 as the divisor may be used. 
17.  Paper-Drift Corrections. A paper-drift line will be drawn and 
corrections will be computed if the check of the zero recording made in 
accordance with J§B4-5.2 indicated a paper-drift of 0.3 ordinate or more 
at any level of the sounding. 
17.1 Entering Paper-Drift Corrections. If paper-drift corrections are 
required, they will be placed, with proper sign prefixed, after the tem- 
perature and humidity ordinates to which recorder and drift corrections 
have been applied. An equal (=) sign will be placed after them, followed 
by the corrected temperature or humidity ordinate values, e.g., 30.0 - 
0.1+0.2 = 30.1 -0.3 =29.8, where -0.1 is the recorder correction, +0.2 
is the drift correction, and -0.3 is the correction for paper-drift. The 
paper-drift correction will be applied to the hypsometer ordinate before 
constructing the hypsometer curve. 
17.2 Computation of Paper-Drift Corrections. If the paper-drift is be- 
lieved to have been gradual, draw the paper-drift line from the left edge 
of the top of the zero trace before release to the bottom of the next zero 
trace. If the record indicates that abrupt changes in the paper alignment 
have occurred, draw the drift line accordingly. The sprocket holes should 
be examined closely to find where the paper began to climb on the pins. 
Continue this drift line from the top of each zero trace to the bottom of 
the next following zero trace through the termination of the sounding. 
17.3 Unadjusted Paper -Drift. Enter the paper-drift correction ofeach 
level immediately to the right of the paper-drift line. If the low refer- 
ence has not been adjusted during the paper-drift, the correction will be 
the ordinate difference between the drift line and the correct ordinate 
value of the zero setting. If the recorder at zero prints to the left of the 
true ordinate of the zero setting, a positive correction will be required. 
If it prints to right, a negative correction will be required. 
Ho oe) FMH#3 
