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south south west at mont marson; and ye third day ye north north east blowed in yese three twons; whence I knew manifestly that ye winds sometimes push back one ye other and that ye strongest carries away that wch is opposite to it.  In ye same [[strikethrough]] time [[/strikethrough]] correspondent observations, I have remarked that a violent west wind having weigned at Loches, there was at ye same time at Paris a west-south west and a west-north-east at Mont Marson wch relates to ye second cause of ye [[strikethrough]] obser [[/strikethrough]] diversity of winds.

I have observed a great diversity of winds at ye same time in ye same place when there was two or three storys of clouds, wch one may explain by supposing that ye higher clouds are ordinarily pushed by ye south winds and that ye lower are pushed by ye north; for when that happens at ye same time, ye clouds of ye first or second story ought to go contrary, and that hinders not but ye clouds much more elevated may be pushed by a west wind wch always reigns when not hindered by [[strikethrough]] ye third principal cause [[/strikethrough]] other causes, or by a west wind produced by ye third principal cause, or by some other particular cause.
  
To observe well this diversity of ye motion of ye clouds, we must reguard the top of some steeple, or some other fixed object that is very high, to ye end that we may compare ye divers motions of ye superior and inferior clouds, for other wise it may be thought that two clouds differently distant from ye earth, go according to opposite directions, when they were driven towards ye same side, because that ye superior appear to go gentlier than those below, when they go as swift and that appearance of slowness may make one judge that they might go to ye opposite sides: It may be supposed that Ye east wind is properly but an appearance of wind, since ye motion of ye air goeth ye same way as ye surface of ye earth.

This contrariety of winds in one, and ye same place in different elevations of ye air may proceed from hence that a great wind wch is carryed along a valley, and wch by consequence is lesser and lower may there incounter another wch occupied in ye air a much greater space, and then ye inferior wind may force one part of ye other to wit that wch is near ye earth wch is permitted its free course in ye higher air where ye higher clouds are; but with two contrary winds are equally strong and of ye same bigness and hight, they stop one ye other and make a calm at ye place of their incounter, and having these [[strikethrough]] heaped [[/strikethrough]] heaped up much air they press it and make it elasticall, whence it happens that that air to get at liberty flows back on both sides and makes two other contrary winds wch have their origin in that place.

If there is a south wind in winter wch comes from far it may push ye very high clouds because that blowing in a tangent line, ye move it goeth towards ye farther distant it is from ye earth; and at last having much condensed ye upper air, ye spring of that air may make a north wind near ye earth wch will push ye raine or snow; this I have sen happen many times.  One may explain after ye same manner all ye winds wch reign thrô ye earth by manye different causes, both generall and particular.

As to storms and great tempests, it is difficult to explain them by ye ordinary causes.  It is observed that when in summmer there falls thick raine and gross drops, they are always accompanied with a very violent wind wch predeedes them some seconds and that its violence ceaseth as soon as ye cloud is passed.  I explain these storms whereas some are capable to overturn trees and carry away ye tiles of houses in ye following manner.

When two winds sufficiently large incline one to ye other 15 or 16 degrees coming from far and wch having heaped up and pushed before them all vapours wch they meet with, and having formed each of them a thick cloud they come to meet one another, they condense ye air in ye [[strikethrough]] air [[/strikethrough]] place of their incounter and make it very elapticall, and according to ye rules of percussion make it go further by one third than either of them; let us suppose that these winds go just enough to make 24 feet in a second wch is ye ordinary swiftness of incommodius and against such it a trouble to go; ye wind composed of two will go swift enough to make 32 feet in a second and ye thick cloud wch they push being elevated 1.2 or 1/4 of a

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