Description and Notes:
This divider comes with the original case and there is a name Jules A. Widmer engraved on one of the arms, but whether this is the maker's or the past owner's signature is not clear (google search returned one Jules A. Widmer who has a number of US patents such as 2310503 and 2320992 issued in 1943). This high-end proportional divider is equipped with rack and pinion micro adjustment mechanism. It is apparently French made as the scales for lines and circles are engraved in French (lignes, cercles), and the font of which is quite different from that of the name.
This instrument is dated to the early 1900 because its appearance is very similar to an example presented in Drawing Instruments 1580-1980 (Fig. 119, p. 126), which has been dated to late 19th century. Also in the 1878 edition of A Descriptive Treatise On Mathematical Drawing Instruments, at p. 107, by comparing to the bar proportional compass, W. F. Stanley stated: "The French method of adjusting the slide, by a rack within one of the grooves and a pinion upon the slide, is less clumsy than the English method, although perhaps not so durable. Altogether, by comparison, its merits appear greater than its defects."