Casella CEL Fortin barometer - Manual (Page 9)

HB3121
9
The height of the mercury column can now be read on the scale using the vernier.
The diagram below gives an example.
For mmHg the reading is 1000mm, the units reading is made by lining up exactly a
number on the inner scale with a division on the outer, in the example the units are
3. Therefore the reading for the example is 1003 mmHg.
Example vernier reading
CORRECTION OF READINGS TO STANDARD CONDITIONS
The barometer scale is correct at: -
•
0
°
C
•
Standard gravity 980.665cm/s
2
Barometer readings have to be corrected to the value that would have been
obtained if the mercury and the scale had been at their standard temperatures.