84 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 79 



George's to Hamilton and the great difficulty there 

 of obtaining a good site for the erection of the 

 Observatory." (Ms. Return, March 1870.) 



In 1 90 1 the name of the station is changed to Prospect, but 

 apparently without any change of site, the height 

 remaining as 151 ft. 

 Changes of Insinimcnt: 



1866, January to 1872, December. Bar. No. 34. Negretti and 

 Zaml)ra. Index correction +.031 in. applied. 



1873, January, probably to 1920 December. Bar. No. 10, 

 Negretti and Zambra. Index correction 1873 to 

 1893 +.010 in., 1894 probably to 1910 +.012 in. 

 (no information is available as to the reasons for 

 these changes of index correction). 1911-1920, 

 index correction given as +.010 in. 

 Hours of Observation: The combination -1(9''+ 15^') has been 

 adopted as a standard. 



From 1866 to 1888 observations were taken at 9'^ and 15'' 



From 1889 to 19 10 observations were taken at 9'^ and 2i'\ 

 The mean 4(9^ + 21^^) has been reduced to 4(9'^ + 

 15'') by means of the corrections given in table B. 

 which were obtained from observations and 1 5'^ and 

 20'' 4 1'" during the years 1913 to 1918. 



From 1911 to 1920 observations were taken 8'' 41"', 15^' 

 and 20'' 41™. The ol)servation hour of 8'' 41'" was 

 accepted as equivalent to 9'' and the mean -J (8'' 

 41^+15'^) was adopted for this period. 



The observation hour of 20'' 41'" was accepted as equiva- 

 lent to 21'^ in calculating the corrections given in 

 table B. 



From April to October 1919 inclusive observations were 

 taken at 7^'^ and 14'^ This combination has been 

 accepted as equivalent to 2(9+15'^ and no cor- 

 rection has been applied. 

 Notes: From January 191 1 to March 1914 the printed reports 

 accepted as equivalent to Ko'^+^S'^ ^"*^ "^ cor- 

 rection + .010 in." and from February 1912 to 

 December 1920 the pressure columns are headed 

 " Corrected for index error and gravity and re- 

 duced to 32° F." In March 19 14 it was pointed out 

 that the appropriate gravity correction for Ber- 



