Williams and Samuel Jones were two brothers who, at the death of George Adams at the end of the 18th century, bought the rights and all his material. Adams had been one of the biggest promoters of microscopes in the previous years. It is believed that William had worked with him, as well as with Benjamin Martin, another of the great pioneers of the time. They first settled at 135 Holborn Hill Street and in 1800 they moved to 30 Holborn Hill, where they built a wide variety of scientific instruments. William died in 1831 and his brother continued the business until 1860. Different manufacturers settled around him, including Francis Day, at 37 Poultry Street, who manufactured their own optics and bought mechanical accessories from the same manufacturers as the Jones brothers. and others (Dollond, Bate, ...). Perhaps they did not achieve as excellent optics as the first ones, but their instruments were identical, of great beauty.
This model belongs to the design known as "The Most Improved Microscope" by the Jones brothers. It was presented in a similar version in 1797 and it is considered the complete development of the model designed by John Cuff half a century before, since it incorporated all the advances and accessories of the time, such as "Bullseye", "live-box", tweezers, different objectives and a condenser under the observation deck. The microscope is perfectly preserved, having all its accessories and a curious set of 6 objectives housed in a revolver mechanism that allowed different magnifications to be obtained just by turning it.
References: "Billings Microscope Collection" pag 22, fig. 39
H. Moe, "The Story of the Microscope", pag 124
G. Turner, Collecting Microscopes, pag 56-72