subtracting 12.7 from 750, and taking 737.3 mm. to be the true
barometric pressure.

The vapour tensions for temperatures from 0∞ C. to 20∞ C. are as
follows:--

-------+----------++-------+----------++-------+----------
Temp. | Tension. || Temp. | Tension. || Temp. | Tension.
-------+----------++-------+----------++-------+----------
0∞ | 4.6 mm. || 7∞ | 7.5 mm. || 14∞ | 11.9 mm.
1∞ | 4.9 mm. || 8∞ | 8.0 mm. || 15∞ | 12.7 mm.
2∞ | 5.3 mm. || 9∞ | 8.6 mm. || 16∞ | 13.5 mm.
3∞ | 5.7 mm. || 10∞ | 9.2 mm. || 17∞ | 14.4 mm.
4∞ | 6.1 mm. || 11∞ | 9.8 mm. || 18∞ | 15.3 mm.
5∞ | 6.5 mm. || 12∞ | 10.5 mm. || 19∞ | 16.3 mm.
6∞ | 7.0 mm. || 13∞ | 11.2 mm. || 20∞ | 17.4 mm.
-------+----------++-------+----------++-------+-----------

The _correction for pressure_ is:--Multiply the volume by the actual
pressure and divide by 760.

The _correction for temperature_:--Multiply the volume by 273 and divide
by the temperature (in degrees Centigrade) added to 273.

For all three corrections the following rules hold good. _To reduce to
0∞ C. and 760 mm. dry._

Volume ◊ 0.3592 ◊ (Pressure-tension)
Corrected volume = --------------------------------------
Temperature + 273