98 



Comptes Rendus Hebdomadaires des Seances de I'Academie des Sci- 

 ences, par MM. les Secretaires Perpetuels. Tome XVIII. Nos. 

 19 to 22 inclusive. 4to. 



Tables des Comptes Rendus. Deuxieme Semestre, 1843. Tome 

 XVII. 4to. 



Dr. Patterson presented a communication, entitled " Obser- 

 vations for the Magnetic Dip, made at several positions, chiefly 

 on the South-western and North-eastern portions of the United 

 States, and of the Magnetic Declination at two points on the 

 River Sabine, in 1840, by Major James D. Graham, of the U. 

 S. Corps of Topographical Engineers," which was referred to 

 a Committee, consisting of Mr. Walker, Dr. Patterson, and 

 Professor Frazer. 



An autograph letter from Dr. N. Maskelyne, Astronomer 

 Royal, to the Rev. Dr. Ewing, dated Greenwich, Aug. 4, 1775, 

 in relation to a projected Observatory at Philadelphia, was pre- 

 sented to the Society by Mr. Harrison Hall, and read by the 

 Secretary. 



Greenwich, Aug. 4, 1775. 



Sir, — I received your late favour, together with your observations 

 of the comet of 1770, and some of that of 1769, for which I thank 

 you, and shall, I believe, communicate to the Royal Society as you 

 give me leave. In the present unhappy situation of American affairs, 

 I have not the least idea that any thing can be done toward serecting 

 an observatory at Philadelphia, and therefore cannot think it proper 

 for me to take any part in any memorial you may think proper to 

 lay before my Lord North at present. I do not mean, however, to 

 discourage you from presenting any memorial from yourself. Were 

 an observatory to be erected at Philadelphia, I do not know any per- 

 son at Philadelphia more capable of taking the care of it than your- 

 self. Should Lord North do me the honour to ask my opinion about 

 the utility of erecting an observatory at Philadelphia, I should then 

 be enabled to speak out, being always a well-wisher to the promotion 

 of science. You did not distinguish whether the times of your obser- 

 vations were apparent or mean time. 



I am, sir, 



Your most humble servant, 



N. MASKELYNE. 

 The Rev. Dr. Ewing, 



At No. 25 Ludgate Street. 



