64 INTRODUCTION TO SCIENCE 



MEASUREMENT. In collecting data for scien- 

 tific thinking the fundamental virtue is accuracy, 

 and it is impossible to exaggerate its importance. 

 Science begins with measurement, with which we 

 include, of course, every method of precise reg- 

 istration. 



Many advances, Lord Kelvin said, have owed 

 their origin to protracted drudgery. "Accurate 

 and minute measurement seems to the non-scien- 

 tific imagination a less lofty and dignified work 

 than looking for something new. But nearly all 

 the grandest discoveries of science have been but 

 the rewards of accurate measurement and patient, 

 long-continued labour in the minute sifting of 

 numerical results." In illustration he instanced 

 the discovery of the law of gravitation by Newton, 

 Faraday's theory of specific inductive capacity, 

 Joule's law of thermo-dynamics, and that of the 

 continuity of the gaseous and liquid states by 

 Andrews. 



One of the most instructive recent illustrations 

 of the value of attending to little hints is to be 

 found in the story of the discovery of argon. Lord 

 Rayleigh made a number of precise weighings of 

 the oxygen contained in a carefully weighed and 

 measured glass flask at 15 C. and 760 mm. 

 There were very minute differences in the weights 

 recorded, affecting the fourth decimal place. He 

 then made a series of weighings of pure nitrogen 



