The Three Secretaries 121 



sophical investigation, and the steps by which the widest 

 generahzations and the seemingly intangible conceptions of 

 the higher physics have been securely reached. He exercised 

 his pupils in deducing particular results from admitted laws, 

 and in then ascertaining whether what was thus deduced ac- 

 tually occurred in nature ; and if not, why not. Though very 

 few of a college class might ever afterward undertake a phys- 

 ical or chemical investigation, all would, or should, be con- 

 cerned in the acquisition of truth and its relations ; and by 

 knowing how truth was won and knowledge advanced in one 

 field of inquiry, they would gain the aptitude which any real 

 investigation may give, and the confidence that springs from 

 a clear view and a sure grasp of any one sul^ject. 



" He understood, as few do, the importance of analogy and 

 hypothesis in science. Premising that hypothesis should al- 

 ways be founded on real analogies and used interrogatively, 

 he commended it as the prerequisite to experiment, and the 

 instrument by which, in the hands of sound philosophers, most 

 discoveries have been made. This free use of hypothesis as 

 the servant and avant-courier of research — as means rather 

 than end — is a notable characteristic of Henry." 



In 1830 he married his cousin Miss Harriet L. Alexander, 

 who on the death of her father, Alexander Alexander, an 

 active and successful business man of Schenectady, had come 

 to live in Albany. It was largely through Henry's influence 

 that her elder brother, Stephen Alexander, was called to 

 Princeton in 1833, where he subsequently became" professor 

 of astronomy. Mrs. Henry survived her husband but a few 

 years, and died in Washington City on March 25, 1882. 



The memory of Henry is lovingly cherished at Princeton, 

 where a bronze tablet by Augustus St. Gaudens was erected 

 in 1885, to commemorate his connection with the University.-^ 



IThe memorial address delivered by'Ed- of the most eloquent and satisfactory appre- 

 ward N. Dickerson, LL. D., upon the occa- ciations of the cliaracter and achievements of 

 sion of the presentation of this tablet, is one Professor Henry. 



