the earlier abercrombies have the smaller / lighter cases and the light dials . . . with the later ones (Heuer Mareographe and Orvis Solunagraph), Heuer switched to the black dials and the heavier snap-back cases. it is interesting to look at these two photos, and realize that they were designed with the same movements and functions.

the link below will take you to some additional photos of the Orvis Solunagraph