366 AIM AND PROGRESS OF PHYSICAL SCIENCE. 



the student of science acquires from lectures and books, 

 he requires intelligence which only an ample and diligent 

 perception can give him ; he needs skill which comes 

 only by repeated experiment and long practice. His 

 senses must be sharpened for certain kinds of observation, 

 to detect minute differences of form, colour, solidity, 

 smell, &c., in the object under examination ; his hand 

 must be equally trained to the work of the blacksmith, 

 the locksmith, and the carpenter, or the draughtsman and 

 the violin-player, and, when operating with the micro- 

 scope, must surpass the lace-maker in delicacy of handling 

 the needle. Moreover, when he encounters superior de- 

 structive forces, or performs bloody operations upon man 

 or beast, he must possess the courage and coolness of 

 the soldier. Such qualities and capabilities, partly the 

 result of natural aptitude, partly cultivated by long 

 practice, are not so readily and so easily acquired as the 

 mere massing of facts in the memory; and hence it 

 happens that an investigator is compelled, during the 

 entire labours of his life, to strictly limit his field, and to 

 confine himself to those branches which suit him best. 



We must not, however, forget that the more the in- 

 dividual worker is compelled to narrow the sphere of his 

 activity, so much the more will his intellectual desires 

 induce him not to sever his connection with the subject 

 in its entirety. How shall he go stout and cheerful to 

 his toilsome work, how feel confident that what has given 

 him so much labour will not moulder uselessly away, but 

 remain a thing of lasting value, unless he keeps alive 

 within himself the conviction that he also has added a 

 fragment to the stupendous whole of Science which is 

 to make the reasonless forces of nature subservient to 

 the moral purposes of humanity ? 



An immediate practical use cannot generally be counted 

 on a prioH for each particular investigation. Physical 



