undoubted, the Legitimate Consequences thereof must be allow'd me, let it proceed from what it will.
A second Cause is the uncertain Exhalation and Præcipitation of the Vapours lodging in the Air, whereby it comes to be at one time much more crowded than at another, and consequently heavier; but this latter in a great measure depends upon the former. Now from these Principles I shall endeavour to explicate the several Phænomena of the Barometer, taking them in the same order I laid them down.
- Why in calm Weather the Air being inclin'd to Rain, the Mercury is commonly low? I Answer, That the Mercury's being low, inclines it to Rain; for the Air being light, the Vapours are no longer supported thereby, being become specifically heavier than the Medium wherein they floated; so that they descend towards the Earth, and in their fall meeting with other aqueous Particles, they incorporate together, and form little drops of Rain; but the Mercury's being at one time lower