Bausch & Lomb apparently started to manufacture demonstration microscopes in the 1890's and these evolved over the years. The first model c. 1894, was similar to the earlier Beale and other designs in that it was simply a focusing tube attached to a plate supporting a slide. The 1900 model had an improvement in that the stage had a mortise in the center to accomodate the coverslip or cell in the center of the slide. By 1904 a handle was added, and by 1911 it looked more like a microscope with a 'jug handle'. Variations of the jug handle continued through at least 1922. The only drawback still present in the 1922 model, was that the slide was held in place by stage clips and so as it was passed from student to student, the slide was likely to move unless taped in place.