MIR A CLJS8 AND SPECIAL PRO VID ENCE8. 3 6 1 



mitted to experiment. Torricelli took a glass tube a yard 

 or so in length, closed at one end and open at the other, 

 and filling it with mercury, he stopped the open end with 

 his thumb, and inverted it into a basin filled with the 

 liquid metal. One can imagine the feeling with which 

 Torricelli removed his thumb, and the delight he experi- 

 enced on finding that his thought had forestalled a fact 

 never before revealed to human eyes. The column sank, 

 but it ceased to sink at a height of thirty inches, leaving 

 the Torricellian vacuum overhead. From that hour the 

 theory of the pump was established. 



The celebrated Pascal followed Torricelli with another 

 deduction. He reasoned thus: if the mercurial column be 

 supported by the atmosphere, the higher we ascend in the 

 air, the lower the column ought to sink, for the less will 

 be the weight of the air overhead. He caused a friend to 

 ascend the Puy de Dome, carrying with him a barometric 

 column; and it was found that during the ascent the column 

 sank, and that during the subsequent descent the column 

 rose. Between the time here referred to and the present, 

 millions of experiments have been made upon this subject. 

 Every village pump is an apparatus for such experiments. 

 In thousands of instances, moreover,, pumps have refused 

 to work; but on examination it has infallibly been found 

 that the well was dry, that the pump required priming, or 

 that some other defect in the apparatus accounted for the 

 anomalous action. In every case of the kind the skill of 

 the pump-maker has been found to be the true remedy. In 

 no case has the pressure of the atmosphere ceased; con- 

 stancy, as regards the lifting of pump- water, has been 

 hitherto the demonstrated rule of nature. So also as 

 regards PascaFs experiment. His experience has been the 

 universal experience ever since. Men have climbed moun- 

 tains, and gone up in balloons; but no deviation from 

 PascaFs result has ever been observed. Barometers, like 

 pumps, have refused to act; but instead of indicating any 

 suspension of the operations of nature, or any interference 

 on the part of its Author with atmospheric pressure, 

 examination has in every instance fixed the anomaly upon 

 the instruments themselves. It is this welding, then, of 

 rigid logic to verifying fact that Mr. Mozley refers to an 

 " unreasoning impulse." 



Let us now briefly consider the case of Newton. Before 



