.Triple Achromatic Settings
.........................................................................No.1.........6"x5"
..........................................................................No.2.........81/2 "x 61/2"
..........................................................................No.3....10"x8"
..........................................................................No.4....12"x10"
..........................................................................No.5....15"x12"
..........................................................................No.6....18"x16"
..........................................................................No.7....22"x20"
..........................................................................No.8....25"x21"
......................................................................No.10...36"x36"
Lens Book, Volume 2. 1874-1876
Brent Archive 198028/3/2
Serial numbers 22000-26000