92 
LJ 
ADLER. 
Institute of France, and the medal of the Astronomical 
Society of France. He was a foreign Member of the Royal 
Society of London, a Correspondent of the Institute of 
France, Fellow of the Royal Astronomical Society of Lon- 
don, Member of the Royal Institution of London, Member of 
the Academia dei Lincei of Rome, of the National Academy 
of Sciences, and of many others. 
Mr. Langley, although a member of very many scientific 
and other societies, was not a regular attendant at any of 
them. He systematically avoided holding any office in any 
society, the only exceptions that I know of being his Presi- 
dency of the American Association for the Advancement of 
Science, his acceptance of the Vice-Presidency for a brief 
time of the American Philosophical Society and member- 
ship in the Council of the National Academy of Sciences. 
It was not that he failed to recognize the importance of scien- 
tific societies, but rather that he felt confident that others 
could attend to their management, and that his time must 
be guarded for his official duties and for his scientific work. 
Among the many societies to which he belonged, he had 
an especial affection for this Philosophical Society. He was 
elected to membership in it in 1887, the year in which he 
came to Washington, and with hardly any exception read 
before it the scientific papers that he presented in this 
city. Many of you will probably remember his various 
papers on the infra-red spectrum, and that on mechanical 
flight, and I may be permitted to say in passing that no 
novice ever prepared a paper or lecture more carefully than 
he did, for while he always spoke with great directness and 
simplicity and clearness, apparently without effort and usu- 
ally without notes, his communications were always written 
carefully in advance, every slide gone over, and an actual 
rehearsal made, and this method was one that he carried into 
his scientific work as well. I remember that before going 
on the eclipse expedition to Wadesboro there was a rehearsal 
almost daily for a period of nearly three months, on both 
his own part and that of every other person in the party, 
