1426. 'By means of the barometer' Taylor observes, 'we are enabled to regain, in some degree at least, that foreknowledge of the weather, which the ancients unquestionably did possess; though we know not the data on which they founded their conclusions.' Chaptal considers that the value of the barometer, as an indicator of the approaching weather, is greater than that of the lunar knowledge of the most experienced countryman, and indeed of all other means put together. (La Chimie appliquee, &c.) We shall therefore annex such rules as have hitherto been found most useful in ascertaining the changes of the weather by means of the barometer.
