REPOET OF THE SECRETARY. 109 



more difficult to determine the times from them than was expected, and it seems 

 doubtful if this method is desirable to be employed in future. 



9. Position of the camp. — From observations of stars made on five nights, taken in 

 connection with noon-time signals transmitted from the United States Naval Observa- 

 tory, Mr. Putnam determined the latitude and longitude of the camp to be: 



Latitude 34° 57' o2" north. 



Longitude \^ , "' W west of Greenwich.) 



I 5h. 20m. 17. 8s. i ^ ^ 



The operations of the Astrophysical Observatory during the past year have been 

 distinguished, first, by the publication of the first volume of its Annals, in which the 

 infra-red solar spectrum is the main topic; second, by progress in the preparation of 

 a highly sensitive, steady, and magnetically shielded galvanometer; third, by obser- 

 vations of the total solar eclipse, in which excellent large-scale photographs by the 

 corona were secured, the coronal extensions photographed to upward of three diam- 

 eters from the moon's limb, the absence of intra-mercurial planets above the fourth 

 magnitude made nearly certain and the presence of several such between the fifth 

 and seventh magnitude rendered as probable as single photographs can do, and 

 finally, in which the small but measurable intensity of the total radiations and the 

 effectively low temperature of the inner corona were observed by the aid of the 

 bolometer. 



Eespectfully submitted. C. G. Abbot, 



Aid Acting in Charge Adroplujsical Observatory. 



Mr. S. P. Laxgley, 



Secretary of tJie Sinitftsoiiian Institution, Washington, I). C. 



