182 PROCEEDINGS OF THE AMERICAN ACADEMY 



If now we correct the observed error of the clock at Harvard Col- 

 lege Observatory by the ditfereuce of the personal equations of the 

 observers given above, and reduce the position to the centre of the 

 large dome, Ave have for the assumed error of the clock, as determined 

 at Harvard College Observatory, — 



-f lo'.698 ± 0.026 -f 0».269 — 0».039, 

 which is 



-f 15».928 ± 0».026; 



and for Waltham we have 



4- 43.257 ± 0.031. 



And their difference gives 



— 27'.329 dr 0'.040. 



The most recent determination of the longitude of the centre of the 



dome of the Harvard College Observatory determines it to be east of 



Washington 



0''23"' 41M1; 



whence our final result is that the transit pier in the private observa- 

 tory erected on Crescent Street, by the American Watch Company, at 

 Waltham, Mass., is East of the centre of the dome of the United States 

 Naval Observatory at Washington, D. C. 



O" 23"* 13'.78 ± 0'.04. 

 Harvard College Observatory, November, 1877. 



