xxvi ^GENERAL SUMMARY OF SCIENTIFIC AND 



The new observatory building at Cincinnati has been ded- 

 icated witli appropriate ceremonies. 



A remarkable instance of American scientific enterprise is 

 found in the recent redetermination of the difterence of longi- 

 tude between the observatories of Gi-eenwich and Paris, car- 

 ried out by Mr. J. E. Ililgard under the auspices of the Coast 

 Survey, incidentally to a redetermination of the transatlantic 

 longitude. As many of our readers may be aware, the first 

 determination of the longitude of any point on the American 

 continent from Greenwich by the Atlantic cable was made by 

 Dr. Gould in 18C6. When the French cable from Brest to St. 

 Pierre, and thence to Duxbury, Massachusetts, was got into 

 operation, it was judged advisable to make a separate deter- 

 mination by that means, as a test of the correctness of the 

 results. But the longitude came out more than half a second 

 greater by the last determination, which, however, depended 

 on the longitude of Paris from Greenwich. To discover where 

 the error lay, it was determined to make a third determina- 

 tion, in wliich signals should be exchanged simultaneously 

 between Greenwich, Paris, and Brest, while being sent across 

 the Atlantic. The result showed that the lono-itude of Paris 

 from Greenwich, as determined by Airy and Le Verrier twenty 

 years ago, was more than one third of a second of time, or 

 about one twelfth of a mile, in error. When this error Avas 

 corrected, and some other points settled, the results of the 

 three determinations became remarkably accordant, and set- 

 tled the longitude of the Naval Observatory from Greenwich 

 within a hundred feet. 



The Necrology of the past year embraces the names of the 

 following astronomers: Kaiser, Donati, Chacornac, Schweizer, 

 and Chevallier. 



TERRESTRIAL PHYSICS. 



Earthquakes, as a problem of Terrestrial Physics, and dis- 

 tinct from their geological relations, have been elucidated by 

 the memoir of Seebach on the earthquake of March 6, 1872, 

 by the notes of Graves on the electric earth currents produced 

 by them, and by the notes of Professor Niles on the phenom- 

 ena observed at Monson, Massachusetts. But the crowning 

 work of the year on this subject is that of Mallet. 



In Terrestrial Magnetism the most important i)lacc must 



