24 



FRAGMENTS OF SCIENCE. 



the skill of the pump-maker could not get it to ri 

 The fact was brought to the notice of Galileo, and 

 soured by a world which had not treated his scien 

 over kindly, is said to have twitted the philosophy 

 the time by remarking that nature evidently abhorred 

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

 however, did not solve the problem. It was taken 

 by his pupil Torricelli, to whom, after due ponderin 

 the thought occurred, that the water might be forced in 

 the tube by a pressure applied to the surface of the liqui 

 outside. But where, under the actual circumstan 

 was such a pressure to be found ? After much reflectio 

 it flashed upon Torricelli that the atmosphere mig 

 possibly exert this pressure; that the impalpable 

 might possess weight, and that a column of water thirty 

 two feet high might be of the exact weight necessary 

 hold the pressure of the atmosphere in equilibrium. 



There is much in this process of pondering and i 

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

 of inspiration that we rise from the wise and sedulo 

 contemplation of facts to the principles on which th 

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

 which is gradually cleansed by the effort to think right! 

 and which, when so cleansed, and not before, receiv 

 impressions from the light of truth. This passage from 

 facts to principles is called induction ; 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 accordance with outward fact. 

 To prove or disprove the induction, we must resort to 

 deduction and experiment. 



Torricelli reasoned thus : If a column of water thirty 

 two feet high holds the pressure of the atmosphere ID 

 equilibrium, a shorter column of a heavier liquid oughl 

 to do the same. Now, mercury is thirteen times heaviei 



