INTKODUCTION 



SCIENTIFIC men may be divided into two groups ; the 

 investigators of theory, and the reducers of theory to 

 practice. The workers in applied science have for 

 their aim the material advancement of the human 

 race. Not only do they bring health to the sick and 

 an increase of comfort to us all ; but they help to 

 make every-day work more interesting to the intelli- 

 gent, and thus they lift the toiler to a higher level. 

 Also, by increasing the wealth of the world, they 

 give to some men sufficient leisure to pursue the 

 study of science or of philosophy undisturbed. 



On the other hand, the student of pure science 

 whether he be an astronomer engaged in studying 

 the movements and composition of the starry host, 

 or whether he be a humble entomologist he also 

 has a high object to attain beyond the facts he so 

 industriously gathers together. Consciously or 

 unconsciously he is helping to solve the riddle of the 

 Universe by collecting evidence which may, perhaps, 

 enable us to ascertain the laws which the Creator 

 has imposed upon his work. He is seeking the 

 truth, partly no doubt out of curiosity, but partly 

 because he feels that a knowledge of the truth is 

 of the greatest importance to the human race. We 

 can never know the whole truth about the Universe, 



