IIST THE LAST HALF-CEXTUEY. 39 



ble hypotheses ; to guide observation and 

 experiment by verifiable hypotheses ; and 

 to consider the latter, not as ideal truths, 

 the real entities of an intelligible world be- 

 hind phenomena, but as a symbolical lan- 

 guage, by the aid of which nature can be 

 interpreted in terms apprehensible by our 

 intellects. And if physical science, dur- and con- 

 ing the last fifty years, has attained di- progress. 

 mensions beyond all former precedent, 

 and can exhibit achievements of greater 

 importance than any former such period 

 can show, it is because able men, ani- 

 mated by the true scientific spirit, care- 

 fully trained in the method of science, 

 and having at their disposal immensely 

 improved appliances, have devoted them- 

 selves to the enlargement of the bounda- 

 ries of natural knowledge in greater num- 

 ber than during any previous half-century 

 of the world's history. 



I have said that our epoch can produce The 

 achievements in physical science of great- gr ™t 



