The Watson & sons high resolution mono and binocular microscope was manufactured under No. 62,475. This apparatus corresponds to the transition period to binocular microscopes and offers the possibility of using it as a monocular with a complementary accessory that replaces the two eyepieces. It is also equipped with two plates and a phase contrast device. It is an excellent device for moving preparations. Its optical system and all controls are made of high quality brass. It is a very complete and expensive device. It weighs 5,500 g. It belonged to Sir William Dunn, of the Pathology School of the University of Oxford.