Andrew Ross, Large No. 1, 1849
This microscope reflects the popular English bar-limb design first introduced by Andrew Ross in 1842. This design became the standard for many British microscope makers throughout the second half of the 19th century. The British microscopes had long tubes and were based on the bar-limb concept having a Y-shaped base holding an inclining tube that holds the mirror, stage, rack and pinion system for coarse focusing and the "bar" holding the tube. This concept was maintained by most of the dominant makers of the second half of the 19th century including Powell and Lealand, Ross, Dollond, Baker, and many others. Some conservative companies (i.e., Powell and Lealand) continued the manufacture of bar-limb microscopes into the 20th century, long after the improved continental design.
This large binocular microscope is signed on the 'Y' shaped foot, 'A. ROSS, LONDON, No 398' should date to 1849. Ross did not include serial numbers to his microscopes before August 1842.