MEDI/EVAL SCIENCE IN THE WEST 



round hole through the shutter of a darkened room, 

 the reversed image of objects outside being shown on 

 the opposite wall. 



Like other philosophers in all ages, he had observed 

 a great number of facts which he was unable to ex- 

 plain correctly. But such accumulations of scientific 

 observations are always interesting, as showing how 

 many centuries of observation frequently precede 

 correct explanation. He observed many facts about 

 sounds, among others that blows struck upon a bell 

 produced sympathetic sounds in a bell of the same 

 kind; and that striking the string of a lute produced 

 vibration in corresponding strings of lutes strung to 

 the same pitch. He knew, also, that sounds could 

 be heard at a distance at sea by listening at one end of 

 a tube, the other end of which was placed in the water ; 

 and that the same expedient worked successfully on 

 land, the end of the tube being placed against the 

 ground. 



The knowledge of this great number of unexplained 

 facts is often interpreted by the admirers of Da Vinci, 

 as showing an almost occult insight into science many 

 centuries in advance of his time. Such interpretations, 

 however, are illusive. The observation, for example, 

 that a tube placed against the ground enables one to 

 hear movements on the earth at a distance, is not 

 in itself evidence of anything more than acute scien- 

 tific observation, as a similar method is in use among 

 almost every race of savages, notably the American 

 Indians. On the other hand, one is inclined to give 

 credence to almost any story of the breadth of knowl- 

 edge of the man who came so near anticipating Hutton, 



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