BACKWARDNESS OF THE ANCIENTS. 



445 



they acquire an elasticity and a strength, for the maintenance of 

 which the most attenuated vapor affords sufficient nourishment. 



However incomplete this summary of Plutarch's voluminous trac- 

 tate, it will serve to convey some idea of the state of astronomy and 

 physics among the Greeks. In it we look in vain for simple recogni- 

 tion of the facts, or for any just apprehension even of the most ele- 

 mentary principles. Approaching their inquiries with foregone con- 

 clusions, they had decided the causes of phenomena long before they 

 came fairly within range of them. 



The point therefore is, not merely what we see, but also how we 

 see ; we must be able to critically examine what we have seen, and, 

 above all, Ave must be able to recognize those features of the object 

 which are of importance. And, as in the foregoing examples we 

 have shown that in the domain of science mere seeing was not the 

 strong point of the ancients, so it can be proved that they were even 

 less distinguished for reflex seeing. By way of antithesis to a gener- 

 ally-received proverb, we may with more justice, though less poetry, 

 declare that the simplicity of the child's understanding dwells on what 

 is unimportant, but commonly passes by unnoticed what is really of 

 moment. The senses, it is true, supply the material the conscious, 

 or mediate substructure for the grandest systems of thought ; but 

 yet in their further development they must be subject to the action 

 of the culture to which they themselves gave rise. Though at first 

 they were our preceptors, now they are oftentimes our pupils. In 

 seeing we have, perhaps, more need of the understanding than of the 

 eye, just as in walking we could better dispense with strong legs than 

 with sound lungs. The disciplined eye, though of feeble power, de- 

 scries more objects difficult to be discerned than the strong but un- 

 practised organ. This is true of the microscope and telescope as well 

 as of the naked eye; and the student of Xature to-day, even with the 

 imperfect instruments of his predecessors, sees much more than they. 

 Who is there that has not innumerable times had experience of the 

 dependence of the senses on the understanding, in the fact that, when 

 he is intent on seeing a definite object, his eye becomes almost insen- 

 sible to all other objects ? Thus, one who is searching in a garden 

 for red berries is quite unconscious of the blue berries which stand 

 side by side with the red. 



We have in German a term which very happily expresses the 

 faculty, possessed by the most eminent of scientific geniuses, of dis- 

 covering the important phases of ordinary phenomena : such men are 

 said to have " Blick." Have we not an instance of a higher visual 

 faculty, exalted not only by genius, but also by comprehensive knowl- 

 edge, when a Gauss was led by the glistening of the windows of a 

 church-tower which he was observing with his telescope to the idea 

 of his heliotrope an instrument without which no accurate triangu- 

 lation is nowadays ever thought of; or when a Rittenhouse, in the 



