A fine pair of binoculars, circa 1890. Unusually for this era they are constructed from aluminium. With 1½ inch/3.75 cm diameter objective lenses, a central focus adjustment wheel, adjustment for the interocular distance and stitched textured leather covering.
Many binoculars from this era use a Galilean optical design producing a compact instrument with an upright image, but have a relatively low magnification and narrow field of view. Keplerian optics, such as those employed in these binoculars, offer higher magnification and a wider field of view, but the image produced is inverted. To flip the it upright, each tube uses additional erecting lenses which means the tubes have to be longer.
