Honorary Membership was limited to 10 from 1890-1900, and to 15 from 1901 onwards. Corresponding Membership was a lesser class of Honoris causa membership in the early years. A few honorary members, such as Barnard, were first made corresponding members for a short time before being recommissioned as honorary members.
| Nation(s) | Start |
End |
|
|---|---|---|---|
| Clerke, Miss Agnes M. | United Kingdom | 1891 | 1907 |
| Vogel, Dr. Hermann C. | Germany | 1894 | 1907 |
| Newcomb, Rear Admiral Dr. Simon | USA | 1891 | 1909 |
| Gore, Mr. John Ellard | Ireland | 1891 | 1910 |
| Huggins, Dr. Sir William | United Kingdom | 1891 | 1910 |
| Terby, M. François J. | Belgium | 1894 | 1911 |
| Darwin, Dr. Sir George Howard | United Kingdom | 1894 | 1912 |
| Swift, Dr. Lewis A. | USA | 1903 | 1913 |
| Ball, Dr. Sir Robert Stawell | United Kingdom | 1894 | 1913 |
| Holden, Dr. Edward S. | USA | 1891 | 1914 |