Description and Notes:
The maker's signature printed on the case is C. Riefler, Nesselwang (Bayern), in which Bayern is Bavaria in German. A brief history of the manufacturer can be found in Drawing Instruments, 1580-1980, p. 29, by Maya Hambly as follows:
Founded in 1841 outside the neighboring town of Nesselwang by Clemens Riefler (1820-76), following his apprenticeship with Ertel in Munich. Riefler's firm eventually combined the manufacture of drawing instruments with other precision instruments such as chronometers, and later specialized in electric clocks. By 1877, the funder's son, Sigmund Riefler (1847-1912), had patented a design for cylindrical pattern compasses, known as 'the round system', which were light and easy to handle. This was the first design which could be made by machine production and where the inserts fitted securely without screw: a pattern which has continued to be made, with some modifications, until today.
The company still exist today and specialized in making drafting furniture and CAD equipment in Nesselwang, their official homepage can be found here.
Unlike the commonly encountered round system sets which are made of German silver, this is a brass set and the profile of the joint of the compass and divider are straight instead of being milled into an aesthetically appealing concave curve. Besides, the lining of the case is felt instead of velvet. I was kindly informed by a fellow collector that the Round system instruments were made in three grades, A, B and C where A is the German silver sets and C being School grade instruments made out of Brass. The grade would be indicated in the set number stamped on the case, such as "A27" or "C27." However a close inspection of the case of this set found that the code stamped on the left upper corner looks like "A30" or "A36," the digits are not very legible but the first letter is definitely an A. As this set closely resembles the ones shown on a Riefler brochure from 1954, it is suspected that it may have been produced during the war time, but this can not be confirmed without further evidence. Nontheless the maker's mark has been stamped on all of the instruments. This is consistent with the following declaration found in the 1893 Special exhibition catalogue of the Deutsche mechanic and optic manufacturers:
The drawing instruments, which form a speciality of the firm, are of the construction shown in the illustrations and are well known in the technical world as "Riefler's Round System Compasses." The popularity which they have attained is a sufficient proof of their excellence of construction and workmanship, which is secured by a number of special machines fitted with the latest improvements. It will be well to here mention that poor imitations of these instruments are placed upon the market; to prevent these being confounded with the Riefler instruments each of the latter has the name of "Riefler" stamped upon its head.
The empty slot at the lower right corner of the case is for the ruling pen of the drop bow compass, which is missing when acquired. The shorter ruling pen is a later replacement.