352 PHYSICAL SCIENCE IN THE MIDDLE AGES. 



grand structures of Cologne, or Amiens, or Can- 

 terbury, could not have been erected without a 

 profound knowledge of mechanical principles. 



To this we reply, that such knowledge is mani- 

 festly not of the nature of that which we call 

 science. If the beautiful and skilful structures of 

 the middle ages prove that mechanics then existed 

 as a science, mechanics must have existed as a 

 science also among the builders of the Cyclopean 

 walls of Greece and Italy, or of our own Stone- 

 henge; for the masses which are there piled on 

 each other, could not be raised without consider- 

 able mechanical skill. But we may go much fur- 

 ther. The actions of every man who raises and 

 balances weights, or walks along a pole, take for 

 granted the laws of equilibrium ; and even animals 

 constantly avail themselves of such principles. Are 

 these, then, acquainted with mechanics as a science ? 

 Again, if actions which are performed by taking 

 advantage of mechanical properties prove a know- 

 ledge of the science of mechanics, they must also 

 be allowed to prove a knowledge of the science of 

 geometry, when they proceed on geometrical pro- 

 perties. But the most familiar actions of men and 

 animals do this. The Epicureans held, as Proclus 

 informs us, that even asses knew that two sides 

 of a triangle are greater than the third. And they 

 may truly be said to have a practical knowledge 

 of this; but they have not, therefore, a science of 

 geometry. And in like manner among men. if we 



