404 NATURAL HISTORY. 



light motion of the spirits, which the thinness of the 

 skin, and suddenness and rareness of touch do fur 

 ther : for we see a feather, or a rush, drawn along the 

 lip or cheek, doth tickle ; whereas a thing more ob 

 tuse, or a touch more hard, doth not. And for sud 

 denness, we see no man can tickle himself: we see 

 also that the palm of the hand, though it hath as thin 

 a skin as the other parts mentioned, yet is not 

 ticklish, because it is accustomed to be touched. 

 Tickling also causeth laughter. The cause may be 

 the emission of the spirits, and so of the breath, by a 

 flight from titillation ; for upon tickling we see there 

 is ever a starting or shrinking away of the part to 

 avoid it ; and we see also, that if you tickle the 

 nostrils with a feather, or straw, it procureth sneez 

 ing ; which is a sudden emission of the spirits, that 

 do likewise expel the moisture. And tickling is 

 ever painful, and not well endured. 



Experiment solitary touching the scarcity of rain 

 in Egypt. 



767. It is strange, that the river of Nilus overflow 

 ing, as it doth, the country of Egypt, there should be, 

 nevertheless, little or no rain in that country. The 

 cause must be either in the nature of the water, or 

 in the nature of the air, or of both. In the water, it 

 may be ascribed either unto the long race of the 

 water ; for swift-running waters vapour not so much 

 as standing waters ; or else to the concoction of the 

 water ; for waters well concocted vapour not so much 

 as waters raw ; no more than waters upon the fire 



