I9I4.] MINUTES. 



XI 



Vice-President Pickering in accepting the portrait, said : 



My acquaintance with Samuel Pierpont Langley goes back to the 

 winter of 1870, when we crossed the ocean together to observe the 

 total eclipse of the sun, in Spain. We maintained an unbroken 

 friendship until his death, nearly forty years later. As a young man 

 he was enthusiastic, and full of hope for the future. When placed 

 in charge of the observatory at Pittsburgh, he found that the smoke 

 in the atmosphere rendered stellar observations difficult. He there- 

 fore selected the sun as his object for study, since the smoke by cut- 

 ting ofif the heat, rendered the air more steady. A skillful draughts- 

 man, his drawing of that complicated object, a large sunspot, is 

 probably the best ever made. In accepting the position of secretary 

 of the Smithsonian Institution, he stipulated that he should be 

 enabled to continue his scientific investigations. This led to the estab- 

 lishment of the astrophysical observatory, which has continued and 

 extended his work to the present time. He devoted many years to 

 the construction and improvement of the bolometer, one of the most 

 delicate devices for measuring heat, and a most difficult instrument 

 to adjust and use. For many years, the question of artificial flight 

 had an absorbing interest for him. His investigations were long and 

 laborious, and finally he attained success with a small model. When 

 constructing a larger instrument, his sensitiveness induced him to 

 avoid publicity, thus greatly annoying those whose business it is to 

 keep the public informed of the latest news. They had their revenge 

 when a misplaced nail in his launching apparatus ruined his aeroplane 

 on its trial trip, and the subsequent ridicule and criticism saddened 

 his last days, and shortened his life. The success of aerial naviga- 

 tion is largely due to his work, which has only received the credit it 

 deserves since his death. 



Langley, by his devotion to the advancement of human knowledge, 

 well deserves a place among those whose portraits adorn these walls, 

 and in the name of the American Philosophical Society held at Phila- 

 delphia for Promoting Useful Knowledge, I accept this portrait and 

 extend grateful acknowledgments to the donors. 



The following papers were read : 

 " The Magnetic Phenomena of Sun-spots." 



