A: 2/3 inch Swift & Son, London, 5mm WD
B: 1 1/2 inch Ross, London, #21937, 1cm working distance (WD)
C: 1/12 inch "Oel-Immersion"
D: 1/4 inch Watson & Sons, London, 2mm WD with correction collar
Ross low magnification objective
Swift & Son 2/3" objective
Watson & Sons objective with correction collar. The screw threads for this objective do not match the threads in the nosepiece.
1/12" oil immersion objective