XET. VIII- OF THE NATURE OF THE TIDES. I39

times, when the moon passes the meridian; be-cause her action on the particles of air, must, atthat time, make them much lighter. But itmust be considered, that in proportion as theseparticles are rendered lighter, a greater numberof them are accumulated, till the deficiency ofgravity is made up by the height of the column;and as there is then an equilibrium, the pressurewill evidently be the fame as before; and conse-quently the mercury in the barometer, cannot,in any respect, be affected, by means of thesetides.

/

LET-