PHENOMENA OF THE UNIVERSE. 139 



Air forcibly condensed becomes colder and seems to ap 

 proach nearer the nature of water, as when we raise the wind 

 with a fan, we perceive the air with a hurried motion by 

 pressing forward, beating back again, or as when by draw 

 ing our lips together, the breath becomes cold, or as may 

 be seen in bellows. 



And when in the open air, you will find that it is much 

 cooler when the wind is blowing than when the air is per 

 fectly calm. 



In the generation of sounds air condensed imitates the 

 nature of a solid body, for as between two solid bodies 

 sound is produced by percussion, so a sound is produced 

 between a solid body and air condensed, and again between 

 two opposite bodies of condensed air. For with respect to 

 the chords in musical instruments it is plain that the sound 

 is not emitted by touch, or by the percussion between the 

 finger or the bow, but between the chord and the air. 



For a chord when it rebounds, and that with celerity 

 from its being stretched, first condenses the air, and then 

 strikes it. Instruments also put into sound by the breath, 

 on account of the very weak motion of the breath compared 

 with that of a stringed instrument, are of necessity made 

 hollow to assist the compression of the air, which is also 

 considered an assistance in stringed instruments. 



Water pent up makes a way for itself with a powerful im 

 petus, and diffuses itself on all sides, in order to obtain its 

 natural latitude, as under the arches of bridges. In the same 

 manner also wind narrowed and condensed bursts forth with 

 violence. Whirlpools produce whirlpools, for since the 

 natural relaxation is impeded, each part sustains an equal 

 pressure. 



Water emitted on a sudden with force from a confined 

 space, reflects the resemblance of a continuous body, as of 

 a thread or rod, or branch of a tree, and becomes straight, 

 afterward bends, then divides itself, and disperses itself 

 into a circle into drops, as in little pipes, or syringes, and 

 gutters. 



There is a kind of pool not uncommon in ponds, espe 

 cially after hay has been mown, or rather seen from that 

 circumstance. The hurricane sometimes raises a quantity 

 of hay in the air, and carries it along for a time together and 

 not scattered, until after it has been borne to a considerable 

 height, the hay disperses itself and forms, as it were, a 

 canopy. 



A wooden platter, empty and turned downwards, and 

 placed evenly on the surface of the water, and afterward 



