THE SEMI-CENTENNIAL ANNIVERSARY 93 



Rittenhouse's observation of this transit were the only valuable 

 ones taken at this time, for, unfortunately for the European ob- 

 servers, they had cloudy weather. Rittenhouse had beautifully 

 clear weather; and for 105 years, until the next transit occurred, 

 which most of us remember in 1874, his observations were the 

 basis of the astronomers for that period. For this transit Ritten- 

 house built three observatories, one of them immediately in the 

 rear of the present building of the American Philosophical 

 Society in Independence Square itself; and it is an interesting 

 fact that it was from the balcony of this little observatory that, on 

 the 8th of July, 1776, the first public reading of the Declaration 

 of Independence took place. Moreover, we have in our archives, 

 not only the chair upon which the Declaration of Independence 

 was written by Thomas Jefferson — his library chair — but we 

 have also the first rough draft of it with the corrections or sug- 

 gestions of law, and we have also one of the rarest of historical 

 documents, a broadside that was posted on the walls and fences 

 of the town in 1776; and all of these precious relics, with many 

 others, are exposed today, in a combustible building, erected in 

 1887, to the risks of fire. 



Of course the Revolutionary War broke up, very largely, our 

 scientific meetings, but they were resumed immediately after the 

 war, and at intervals, in fact, during the war. 



In 1790 occurred the death of Franklin, and five years later 

 the death of Rittenhouse. Eulogies were pronounced before the 

 Philosophical Society upon both of these distinguished men, and 

 these meetings were attended by the President of the United 

 States, by both houses of Congress, by the diplomatic corps, by 

 the judges, and the various public citizens who were invited. 



Jefferson, I might say, was our president for eighteen years, 

 and incidentally I might remark that during eight years of those 

 eighteen he was also filling the minor office of President of the 

 United States. (Laughter.) It is the unique distinction of the 

 Philosophical Society that we have furnished eight presidents of 

 the United States, from Washington to Wilson. (Applause.) 

 They were elected to the Philosophical Society not because they 

 were presidents, for their election preceded their presidency, but 



