5.
Leads from cell 1 are moved to cell 2 of the transport standard and
the difference between cell 2 of the transport standard and cell A of the
LAB standard is measured. Enter the observed value, with proper sign, is
entered in observation block number 2 (this is the value of cell 2 - (minus)
cell A).
6.
Leads from cell A are moved to cell B of lab standard and measure the
difference between cell 2 of the transport of the transport standard and
cell B of the lab standard is measured.
The observed value, with proper
sign, is entered in observation block number 3 on the second line (this is
the value of cell 2 - (minus) cell B).
7.
The leads are alternately moved and make the measurements are made as
required to obtain observations four through eight to complete the remaining
five observations of this series.
8.
The equipment is connected as shown in Figure 3-6 and measure the
difference between cell A of lab standard and cell 3 of transport standard
is measured.
The observed value, with proper sign, is entered in
observation block number 9 of the next line (this is the value of cell A -
(minus) cell 3).
Note that the positive EMF lead of the potentiometer is
now connected to the lab standard and the negative lead to the transport
standard.
9.
The leads are alternately moved and the measurements are made as
required to obtain observations numbered 10 through 16 to complete the
remaining seven measurements of this series.
NOTE
The position of the potentiometer EMF-REVERSAL switch
is governed by the actual difference between the cell
EMFs. When the switch is in the "+" position the sign
for the observation is positive (+), and when in the
"-" position, the sign is negative (-).
Figures 3-5
and 3-6 reflect typical switch observations for
observations when the temperature of the transport
standard is significantly lower than that of the lab
standard.
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