HELMHOLTZ IN KONIGSBERG 



shunned publicity for the greater part of his life, there 

 is little of incident to relate. 



The stream of original papers began to flow in 

 1850, and it increased in volume until he moved to 

 Bonn in 1856. One is astonished at the number of 

 researches of first-rate importance. Helmholtz did 

 not, like many, lose time in doing second-rate work 

 that others, perhaps, could have done better. His 

 scientific instinct appeared to guide him often into 

 what are termed virgin fields. Thus he had the 

 great satisfaction of collecting the first fruits, and he 

 usually gathered so well as to leave little for others 

 who came after him. Hence the researches and dis- 

 coveries that were announced in rapid succession were 

 always epoch making, and always in a special sense 

 his own. During this period he measured the rate 

 of the nervous impulse, he invented the ophthalmo- 

 scope, and he began those investigations on colour 

 and sound that will for ever be associated with his 

 name. 



The measurement of the rate of the nervous im- 

 pulse was accomplished in 1850. The problem was 

 to measure the rate at which the nervous impulse 

 travels along a sensory nerve, say from the tip of the 

 finger to the brain, or along a motor nerve, say from 

 the brain to one of the muscles of the arm. When 

 we touch the finger, no time seems to elapse between 

 the moment of touching and the moment when we 

 are conscious of having touched something. When 

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