CHAPTER XL 



THE VALUE OF INSTRUMENTS. 



WE cannot leave the survey of facts without alluding to the 

 value of instruments in scientific research. 



With true instinct did the ancients, .as soon as they 

 began to study nature, see the necessity of "endowing the 

 human senses with additional power," and of creating aids 

 which could " increase the steadiness of the hand, the strength 

 of the arm," the keenness, compass,, accuracy of vision, the 

 grasp of the mind. To assist the hand, the ruler and the 

 plumb-line ; to assist the arm, the lever and the balance ; 

 to assist the eye, the gnomon and the dioptra; to assist 

 the mind, numbers and imaginary lines (arithmetic and 

 geometry) were ingeniously devised, all of which increased 

 man's natural gifts "and guided his early footsteps in the 

 path of knowledge. This fact, which history, philology, and 

 archaeology show us to have obtained in remote antiquity, 

 was one which every age, every country, every race has 

 accentuated more and more as time rolled on. In Egypt, 

 in Greece, in Asia, in Europe, century after century con- 

 trived new means, invented new agents, created new imple- 

 ments, machines, appliances, until such a degree of progress 

 was reached that it became impossible to take one step 

 in any pursuit without the succour of instruments the 

 senses becoming secondary guides, and being reduced to 

 the function, so to speak, of simple supervisors and con- 

 trollers. It is not too much to say that a history of 

 instruments would well-nigh amount to a history of science 



