INDISTINCTNESS OF IDEAS. 257 



born from the perishing carcass of some nobler 

 animal. 



2. Indistinctness of Ideas in Mechanics. But 

 the indistinctness of thought which is so fatal a 

 feature in the intellect of the stationary period, 

 may be traced more directly in the works, even of 

 the best authors, of those times. We find that they 

 did not retain steadily the ideas on which the 

 scientific success of the previous period had de- 

 pended. For instance, it is a remarkable circum- 

 stance in the history of the science of Mechanics, 

 that it did not make any advance from the time of 

 Archimedes to that of Stevinus and Galileo. Archi- 

 medes had established the doctrine of the lever; 

 several persons tried, in the intermediate time, to 

 prove the property of the inclined plane, and none 

 of them succeeded. But let us look to the attempts ; 

 for example, that of Pappus, in the eighth Book of 

 his Mathematical Collections, and we may see the 

 reason of the failure. His Problem shows, in the 

 very terms in which it is propounded, the want of 

 a clear apprehension of the subject. " Having given 

 the power which will draw a given weight along 

 a horizontal plane, to find the additional power 

 which will draw the same weight along a given 

 inclined plane." This is proposed without previ- 

 ously defining how Powers, producing such effects, 

 are to be measured; and as if the speed with 

 which the body were drawn, and the nature of 

 the surface of the plane, were of no consequence. 

 VOL. i. S 



