CENTURY VIII. 393 



be caused but by the air, which then beginneth to 

 condense ; and so turneth within that small mold 

 into a degree of moisture, which produceth weight. 

 So it hath been observed, that tobacco cut, and 

 weighed, and then dried by the fire, loseth weight ; 

 and after being laid in the open air, recovereth 

 weight again. And it should seem, that as soon as 

 ever the river beginneth to increase, the whole body 

 of the air thereabouts suffereth a change : for, that 

 which is more strange, it is credibly affirmed, that 

 upon that very day when the river first riseth, 

 great plagues in Cairo use suddenly to break up. 



Experiments in consort touching sleep. 



744. Those that are very cold, and especially in 

 their feet, cannot get to sleep : the cause may be, for 

 that in sleep is required a free respiration, which cold 

 doth shut in and hinder ; for we see that in great 

 colds, one can scarce draw his breath. Another 

 cause may be, for that cold calleth the spirits to suc 

 cour, and therefore they cannot so well close, and go 

 together in the head, which is ever requisite to sleep. 

 And for the same cause, pain and noise hinder sleep ; 

 and darkness, contrariwise, furthereth sleep. 



745. Some noises, whereof we spake in the hun 

 dred and twelfth experiment, help sleep : as the blow 

 ing of the wind, the trickling of water, humming of 

 bees, soft singing, reading, &c. The cause is, for that 

 they move in the spirits a gentle attention ; and what 

 soever moveth attention without too much labour still- 

 eth the natural and discursive motion of the spirits. 



VOL. IV. A A 



