INDEX TO CONTRIBUTORS. 45 



B. A. Gould. 



PAGE 



5*7 The progress of the National Observatory at Cordoba, 

 88. The progress of bis astronomical work at Cordoba. 



A. Hall. 



23. Elements of the Comet I, 18T1. 



28. Astronomical photography. 



30. A curve of the fourth degree. 



34. Astronomical proof of existence of a resisting medium." 



62 Determination of the ratio of circumference to diameter. 



62. Historical note on the method of least squares. 



88. The rectilinear motion of a particle towards a centre. 



94. Comets and meteors. 



101. Method of writing international scientific telegrams. 



B. Hallowell (of Sandy Springs). 



95. The meteor of Christmas Eve^ 1813. 



W. Harkness. 



31. The physical constitution of the corona of the Sun. 

 34. Spectrum of Encke's comet, and appearance of Tuttle's. 

 34. Remarks on the spectrum of Encke's comet. 



39. Density of the hypothetical resisting medium in space. 



56. Communicates a letter from Captain Tupman. 



64. Measurements of heights by a pocket aneroid. 

 74. Power necessary to drive an astronomical clock. 



96. Distribution of temperature over surface of the globe. 



102. Apparatus to be used in observing transit of Venus. 



Joseph Henry. 



Introduction. Annual Address. 



22. Phenomena of sound and e.Kperiments with tuning forks. 



31. Observations made on a journey to California. 



34. Communicates a letter from Dr. Bessels. 



35. Life and scientific labors of Alexander Dallas Bache. 

 42. Communicates a report on meteorite by Mr. Farquhar. 



46, 48. Remarks on the phenomena of the aurora. 

 53. Expenditure of the income of the Bache fund. 



63. Fluctuations of the river Nile. [signals. 



65. Abnormal phenomena of sound in connection with fog 

 T5. On atmospheric electricity. 



