24 FRAGMENTS OF SCIENCE. 



sion, the gardeners of Florence, while attempting to 

 raise water to a very great elevation, found that the 

 column ceased at a height of thirty-two feet. Beyond 

 this all the skill of the pump-maker could not get it to 

 rise. The fact was brought to the notice of Galileo, 

 and he, soured by a world which had not treated his 

 science over kindly, is said to have twitted the philoso- 

 phy of the time by remarking that nature evidently 

 abhorred a vacuum only to a height of thirty-two feet. 

 Galileo, however, did not solve the problem. It was 

 taken up by his pupil Torricelli, to whom, after due 

 pondering, the thought occurred, that the water might 

 be forced into the tube by a pressure applied to the 

 surface of the liquid outside. But where, under the 

 actual circumstances, was such a pressure to be found? 

 After much reflection, it flashed upon Torricelli that 

 the atmosphere might possibly exert this pressure; 

 that the impalpable air might possess weight, and that 

 a column of water thirty-two feet high might be of the 

 exact weight necessary to hold the pressure of the at- 

 mosphere in equilibrium. 



There is much in this process of pondering and its 

 results which it is impossible to analyse. It is by a 

 kind of inspiration that we rise from the wise and sedu- 

 lous contemplation of facts to the principles on which 

 they depend. The mind is, as it were, a photographic 

 plate, which is gradually cleansed by the effort to 

 think rightly, and which, when so cleansed, and not be- 

 fore, receives impressions from the light of truth. 

 This passage from facts to principles is called induc- 

 tion; and induction, in its highest form, is, as I have 

 just stated, a kind of inspiration. But, to make it 

 sure, the inward sight must be shown to be in accord- 

 ance with outward fact. To prove or disprove the in- 

 duction, we must resort to deduction and experiment. 



