OF WINDS. 297 



out of the earth, so some* winds are cast down, and some 

 rise up. As sometimes in rivers there are contrary motions, 

 one of the flowing of the sea, the other of the current of 

 the river, yet both become one motion, by the prevailing of 

 the flood ; so when contrary winds blow the greater subdues 

 the lesser. As in the currents of the sea, and of some 

 rivers, it sometimes falls out, that the waves above go con 

 trary to the waves below ; so in the air, when contrary 

 winds blow together, one flies over the other. As there are 

 cataracts of rain within a narrow space, so there are whirl 

 winds. As waters, however they go forward, yet if they 

 be troubled, swell up into waves, sometimes ascending, 

 grow up into heaps, sometimes descending, are as it were 

 furrowed; so the winds do the same, but only want the 

 motion of gravity. There are also other similitudes which 

 may be observed and gathered out of those things which 

 have already been inquired about. 



Moveable Rules concerning Winds. 



Connexion. 



Rules are either particular or general, both with us are 

 moveable ; for as yet we have not affirmed any thing posi 

 tively. Particular rules may be taken and gathered almost 

 out of every article. We will cull out some general ones, 

 and those but a few, and add thereunto. 



1. Wind is no other thing but moved air; but the air 

 itself moved either by a simple impulsion, or by commixion 

 of vapours. 



2. Winds by a simple impulsion are caused four ways, 

 either by the natural motion of the air, or by expansion of 

 the air in the sun s ways ; or by reception of air thorow a 

 sudden cold, or by the compression of the air by external 

 bodies. 



There may be also a fifth way, by the agitation and con 

 cussion of the air by stars. But let these things be awhile 

 silent, or be given ear unto with a sparing belief. 



3. Of winds which are made by immixion of vapours, 

 the chief cause is the overburthening of the air, by air newly 

 made out of vapours, whereby the mass of the air grows 

 bigger, and seeks new room. 



4. A small quantity of air added causeth a great tumour 

 of the air round about it, so that new air out of the resolu 

 tion of vapours doth confer more to motion than to matter. 

 But the great body of wind consists in the former air, 

 neither doth the new air drive the old air before it, as if 



