100 



simultaneous clang as they struck the ground together sounded the death 

 knell of the old system of philosophy and heralded the birth of the new." 

 The age of reverence for authority had passed away and the day of ex- 

 perimental investigation had dawned. 



In a sense the discoveries of the past few years have resulted in a 

 similar revolution. The revival of the experimental method has been 

 complete. Accepted theories are being put to the test. What we have 

 long regarded as proven facts are being questioned and, in many cases, 

 challenged. There is no field of investigation which has not been culti- 

 vated anew. 



In closing I wish to quote from the presidential address of J. J. Thom- 

 son 1 before the British Association at its last meeting. "The new dis- 

 coveries made in physics the last few years, and the ideas and potentiali- 

 ties suggested by them, have had an effect upon the workers in that sub- 

 ject akin to that produced in literature by the Renaissance. Enthusiasm 

 has been quickened and there is a hopeful, youthful, perhaps exuberant, 

 spirit abroad which leads men to make with confidence experiments which 

 would have been thought fantastic twenty years ago. It has quite dis- 

 pelled the pessimistic feeling, not uncommon at that time, that all the 

 interesting things had been discovered, and all that was left was to alter 

 a decimal or two in some physical constant. There never was any justifi- 

 cation for this feeling, there never were any signs of an approach to finality 

 in science. The sum of knowledge is, at present at any rate, a diverging, 

 not a converging series. As we conquer peak after peak we see regions 

 in front of us full of interest and beauty, but we do not see our goal, we 

 do not see the horizon ; in the distance tower still higher peaks, which will 

 yield to those who ascend them still wider prospects, and deepen the feel- 

 ing, whose truth is emphasized by eveiy advance in science, that 'Great 

 are the works of the Lord.' " 



'Scientific Am. Sup. 63, Xos. 1757 and 1758, pp. 154, 155 and 174-176. Sept. 4 and Sept. 11, 

 1909. 



