MIRACLES AND SPECIAL PROVIDENCES. 59 



know them." Perhaps the best -way of proceeding will be 

 to give one or two examples of the mode in which men of 

 science apply the unintelligent impulse with which Mr. 

 Mozley credits them, and which shall show by illustration 

 the surreptitious character of the method by which they 

 climb from the region of facts to that of laws. 



It was known before the sixteenth century that, the end 

 of an open tube being dipped into water, on drawing an 

 air-tight piston up the tube the water follows the piston, 

 and this fact had been turned to account in the construction 

 of the common pump. The effect was explained at the 

 time by the maxim, "Nature abhors a vacuum." It was 

 not known that there was any limit to the height to which 

 the water "would ascend, until, on one occasion, the garden- 

 ers of Florence, while attempting to raise the water 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 bad 

 not treated his science over-kindly, is said to have twitted 

 the philosophy of the time by remarking that Nature evi- 

 dently abhorred a vacuum only to a height of thirty-two 

 feet. But Galileo did not solve the problem. It was taken 

 up by his pupil Torricelli, who pondered it, and while he 

 did so various thoughts regarding it arose in his mind. It 

 occurred to him that the water might be forced up in the 

 tube by a pressure applied to the surface of the water out- 

 side. 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 

 the 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 

 atmosphere in equilibrium. 



There is much in this process of pondering and its 



