EVOLUTION OF THJ: SCIENTIFIC INVESTIGATOR. 227 



theory l)_v adding' that the distance of the fixed stars was iiiHniteJy 

 greater than the dimensions of the earth's orbit. Even the worhl of 

 j>hih)soi)hy was not yet r(>aily for this conception, and, so far from 

 seeing' the i'easonahl(Miess of the exphination, we find PtokMny argu- 

 ing" ag;ainst the I'olation of the eai'th on grounds which careful oh- 

 sei'vations of the phenomena around liim wouhl have shown to !)e ill- 

 founded. 



Physical science, if we can apply that term to an unco-oi'dinated 

 body of facts, was successfully cultivated from the earliest times. 

 Something must have been known of the properties of metals, and 

 the art of extracting them from tlieii- ores nnist have been practiced 

 from the time that coins and medals were first stam})ed. The prop- 

 erties of the most connnon compounds were discovcH'ed by alchemists 

 in their vain search for the philoso))her's stone, but no actual progress 

 worthy of the name rewarded the practitioners of the black art. 



Perha])S the first approach to a correct method was that of Archi- 

 medes, who by nnu'h thinking worked out the law of the kncr, 

 I'eached the conce})ti()n of the center of gravity, and demonstrated 

 the first principles of hydrostatics. It is remarkable that he did not 

 extend his researches into the phenomena of motion, whether sponta- 

 neous or produced by force. The stationary condition of the human 

 intellect is most strikingly illustrated by the fact that not until the 

 time of Leonardo was any substantial advance made on his discovery. 

 '1\) Sinn up in one sentence the most characteristic feature of ancient 

 and media'val science, we see a notable contrast between the precision 

 of thought implied in the construction and demonstration of geomet- 

 I'ical theorems and the vague indefinite character of the ideas of 

 natural |)lienomena generally, a contrast which did not disai)])ear 

 until the foundations of modern science began to be laid. 



We should miss the most essential point of the ditl'erence between 

 media'val and modern learning if we looked ujion it as mainly a dif- 

 ference either in the precision or the amount of knowledge. The 

 development of both of these qualities would, under any circum- 

 stances, have been slow and gradual, but sure. We can hardly sup- 

 pose that any one genei'ation, or even any one centuiw, would have 

 seen the c()m})lete substitution of exact for inexact ideas. Slowness 

 of growth is as inevitable in the case of knowledge as in that of a 

 growing organism. The most essential point of ditference is one of 

 those seemingly slight ones, the importance of which we are too apt 

 to overlook. It was like the drop of l)lood in the wrong place, which 

 some one has told us makes all the difference betw^een a philoso])her 

 and a maniac. It was all the ditference between a living tree and a 

 dead one, between an inert mass and a growing organism. The tran 

 eition of knowledge from the dead to the living form must, in any 

 complete review of the subject, be looked upon as the really great 



