This instrument is called a "Naturalist's Magnifier" because it is portable and can be carried into the field. While it is not signed, it is certainly of English origin and possibly manufactured by the firm of W&S Jones. This instrument is identical to the W&S Jones Naturalist's magnifier of 1798 as described in Turner, Collecting Microscopes, and the 1789 W&S Jones instrument (AFPI 49172) in the Billings Collection. In all likelihood, therefore, it was made by the firm of William and Samuel Jones of London at the end of the 18th Century.

From 1776 through 1794 William (1762–1831) was an apprentice to his father, John Jones Jr. in the Spectaclemaker's Company. During this apprenticeship William was also a pupil of Benjamin Martin and at some point was employed by George Adams Jr. By 1784 he had joined his father making instruments as "Jones and Son", and by 1794 he and his brother, Samuel, formed the firm of W&S Jones. This firm made scientific instruments from 1794 until 1838 first at 135 Holborn then at 30 Holborn (in 1799). The company was well known for making optical instruments such as their upright, solar, lucernal, and simple microscopes, as well as a planetarium with a clockwork movement. The influence of Benjamin Martin on William is seen in his upright compound microscopes, as their design is similar to instruments made by Martin.

This simple magnifier in the Golub Collection has two stacked plano-convex lenses, an ivory handle, and an adjustable specimen holder that slides in a grooved brass plate for focusing. It can be dismantled and carried in a small case for use in the field. This magnifier is 9.5cm tall by 7cm deep, and magnifies approximately 10x.