From that catalog comes following numbers:However looking at the catalogue from 1890, I suddenly have my doubts.
No.3 - 11 1/2" / 2 1/6" = F5.3
No.5 - 17 1/2" / 3 1/8" = F5.6
...
One of them was sold few days ago: 251021761715Also the later Series IVa catalogued in USA after the new century, 1905 - ish were f7.
Bookmarks