This all brass, compound binocular microscope is an example of Powell & Lealand's Model No. 2, showing the tripod supporting the fine-focus limb. The microscope is actually a "convertible" type instrument that could be either monocular or binocular (as displayed here). Although not the earliest binocular microscope, it may be one of the earliest to use a Wenham prism, which was first employed commercially in about 1860.

Hugh Powell (1799–1883) and Peter Lealand were brothers-in-law who formed a partnership in London in 1841 that became "one of the most famous associations in the history of the microscope." Powell had begun earlier on his own, producing instruments for the trade and marking them with his own name, Hugh Powell, as early as 1840. By 1843 they had designed a large brass instrument incorporating their tripod suspension and "long-lever" fine focusing device. This remained their basic design for over 60 years. For a more thorough discussion of Powell see here.

It is signed Powell & Lealand 1861. There is an engraved dedication on a portion of the movable stage, to Mr. John Harker, with dates of 1855 and 1856, so this stage must have come from an earlier model.

A comparison of Models No.1, 2 is found here.