OBSERVATION OF NATURE. 13 



corded facts and its unanswered questions so immensely multi- 

 plied, that every strictly scientific man must be a specialist, and 

 must confine the researches of a whole life within a comparatively 

 narrow circle. The study I am recommending, in the vaew I 

 propose to take of it, is yet in that imperfectly developed state 

 which allows its votaries to occupy themselves with broad and 

 general views attainable by every person of culture, and it does 

 not now require a knowledge of special details which only years 

 of application can master.* It may be profitably pursued by all : 



peculiar method of shooting. They are able to calculate exactly their own 

 muscular effort, the velocity of the stream, the distance and size of the tor- 

 toise, and they shoot the arrow directly up into the air, so that it falls almost 

 vertically upon the shell of the tortoise, and sticks in it." Analogous calcula- 

 tions — if such physico-mental operations can properly be so called — are made 

 in the use of other missiles ; for no projectile flies in a right line to its mark. 

 The exact training of the eye lies at the bottom of them all, and marks- 

 manship depends almost wholly upon the power of that organ, whose direc- 

 tions the blind muscles implicitly follow. Savages accustomed only to the 

 use of the bow become good shots with firearms after very little practice. 

 It is perhaps not out of place to observe here that our English word aim 

 comes from the Latin astinw, I calculate or estimate. See Wedgwood's Dic- 

 tionary of English, Etymology, and the note to the American edition, under 

 Aim. 



Another proof of the control of the limbs by the eye has been observed in 

 deaf-and-dumb schools, and in others where pupils are first taught to write on 

 large slates or blackboards. The writing is in large characters, the small let- 

 ters being an inch or more high. They are formed with chalk or a slate pen- 

 cil firmly grasped in the fingers, and by appropriate motions of the wrist, 

 elbow, and shoulder, not of the finger joints. Nevertheless, when a pen is 

 put into the hand of a pupil thus taught, his handwriting, though produced 

 by a totally different set of muscles and muscular movements, is identical in 

 character with that which he has practiced on the blackboard. 



For a very remarkable account of the restoration of vision impaired from 

 age, by judicious training, see Lessons in Life by Tlmothy Titcomb, les- 

 son xi. 



It has been much doubted whether the artists of the classic ages possessed 

 a more perfect sight than those of modern times, or whether, in executing 

 their minute mosaics and gem engravings, they used magnifiers. Glasses 

 ground convex have been found at Pompeii, but they are too rudely fashioned 

 and too imperfectly polished to have been of any practical use for optical pur- 

 poses. But though the ancient artists may have had a microscopic vision, 

 their astronomers can not have had a telescopic power of sight ; for they did 

 not discover the satellites of Jupiter, which are often seen with the naked eye 

 at Oormeeah, in Persia, and sometimes, as I can testify by personal observa- 

 tion, at Cairo. 



* The introduction of mathematical method into the study of phj^sical 



