PHILOSOPHICAL SOCIETY OF WASHINGTON. 325 



CONTRIBUTIONS TO SCIENCE AT WASHINGTON. 



In addition to what may be called the public labors of Heniy 

 so diligently performed in various fields after his advent to the 

 Smithsonian Institution, it is well briefly to contemplate the 

 special scientific work he was able to accomplish in the intervaJs- 

 of his exacting occupations ; that some estimate may be formed 

 of the independent value of his later contributions, as well as of 

 his wonderful industry. While still engaged in his difficult task 

 of organizing and shaping the policy of the Institution, in 1850, 

 on taking occasion to present before the American Association 

 at New Haven, Conn., a resume of the electrical phenomena 

 exhibited by the Leyden jar, and their true interpretation, he 

 remarked that " for the last three and a half years, all his time 

 and all his thoughts had been given to the details of the busi- 

 ness of the Smithsonian Institution. He had been obliged to 

 withdraw himself entirely from scientific research ; but he hoped 

 that now the Institution had got under way, and the Regents 

 had allowed him some able assistants, that he would be enabled 

 in part at least to return to his first love — the investigation of 

 the phenomena of nature."* 



Thermal Telescope. — Shortly after his establishment at Wash- 

 ington, he continued a series of former experiments with the 

 " thermo-galvanic multiplicator" devised by Nobili and Mellon! in 

 1831 ; and by some slight but significant modifications of the appa- 

 ratus, be succeeded in imparting to it a most surprising delicacy 

 of action. With the thermo-electric pile carefully adjusted at the 



that lie must see Mr. Lincoln personally, on a matter of vital and pressing 

 importance to the public welfare. This of course secured his admission 

 to the presence of Mr. Lincoln, who was sitting with a middle-aged gentle- 

 man. Observing the hesitancy of bis visitor, the President told him he 

 might speak freely, as only a friend was present. Whereupon the visitor 

 announced that for several evenings past he had observed a light exhib- 

 ited on the highest of the Smithsonian towers, for a few minutes about 

 nine o'clock, with mysterious movements, which he felt satisfied were 

 designed as signals to the rebels encamped on Munson's Hill in Virginia. 

 Having gravely listened to this information with raised eyebrows, but 

 a subdued twinkle of the eye, the President turned to his companion, 

 sayina; " What do you think of that ? Professor Henry." Rising with a. 

 smile," the person addressed replied, that from the time mentioned, lie 

 presumed the mysterious light shone from the lantern of a watchman 

 who was required at nine o'clock each evening to observe and record the 

 indications of the meteorological instruments placed on the tower. 



The painful confusion of Uie officious informant, at once appealed to 

 Henry's sensibility; and quite unmindful of the President, he approached 

 the visitor, offering his hand, and with a courteous regard counselled him 

 never to be abashed at the issue of a conscientious discharge of duty, 

 and never to let the fear of ridicule interfere with its faithful execution. 

 * Proceed. Am. Assoc, 4th Meeting, New Haven, Aug. 1850, p. 378. 



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