"/ often say that when you can measure what you are speaking 

 about and express it in numbers you know something about it; 

 but when you cannot measure it, when you cannot express it in 

 numbers, your knowledge is of a meagre and unsatisfactory kind: 

 it may be the beginning of knowledge, but you have scarcely, in 

 your thoughts, advanced to the stage of science." — Lord Kelvin, 

 in Popular Lectures and Addresses, lecture on Electrical Units 

 of Measurement, 1883. 



