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 | |
|---|---|---|---|
| Russell, Rev. Norman H. | Canada/India | 1898 | 1902 |
| Hale, Dr. George Ellery | USA | 1900 | 1938 |
| Brashear, Dr. John A. | USA | 1901 | 1920 |
| Loewy, M. Maurice | France | 1901 | 1907 |
| Flammarion, M. Camille | France | 1901 | 1925 |
| Barnard, Dr. Edward Emerson | USA | 1901 | 1923 |
| Gonzalez de León, Sr. Luis | Mexico | 1903 | 1914 |
| Swift, Dr. Lewis A. | USA | 1903 | 1913 |
| Wolfer, Prof. Alfred | Switzerland | 1904 | 1931 |
| Campbell, Prof. William Wallace | USA | 1905 | 1938 |