|
This nice example of a pocket survey compass was purchased from Oregon Trail Mercantile in June 2004. They have a great selection of antique and vintage compasses.
Eugene Dietzgen (1862–1929) was born in Germany, moved to the United States in 1878, and formed Luhring & Dietzgen, an engineering supply business, in Chicago in 1885. The firm became Eugene Dietzgen & Co. in 1891, and began manufacturing operations in 1893. The Dietzgen Corporation is still in business today. [Description by Smithsonian NMAH]
Specifications:
- Manufacturer: Dietzgen
- Date of Manufacture: Unknown, but probably in the 1st half of the 20th century.
- Materials:
- Body: Black laquered brass
- Crystal: Glass
- Size: 3-1/8 X 4-1/16 X 3/4
- Needle: Magnetic steel
- Damping: None
- Pivot: post (jewelled?)
- Graduations: Degrees by 20, with short ticks at every degree, medium ticks every 5 degrees and longer ticks every 10 degrees. Formerly luminous points every 10 degrees. Graduation lettering and cardinal points were also in luminous paint, now degraded to a rust red color.
- Declination: none.
- Weight: 9.2 oz, case 2.0 oz.
- Stop: pin actuated by lid when closed. Also a manual button stop under the lid hinge.
- Markings: Outside of lid marked "U.S,. ENGR. DEPT." "E.D.CO. 5990". The "5990" is likely a model number rather than a serial number. Case is marked on the flap "DIETZGEN".
- Description: This is a prismatic survey compass. "Prismatic" refers to the use of a prism, which is mounted in a brass holder and attached to the compass body with a hinge. The prism is folded out for storage, and rotated 180 degrees into place as shown above when in use. The prism magnifies and displays to the eye the degree markings underneath the prism (which are in reverse lettering for just this purpose) when shooting a bearing. The bearing is shot through a slot in the top of the prism housing, and alinged with a sight vane in a slot in the lid. When brought very close to the eye, the user sees the target in the distance, framed by the slot, with the sight vane and prism slot allowing for a precise alignment, and the graduations and bearing marks shown underneath.
- Damage: Various small nicks and scratches on outer case. Black laquer is wearing off of the screw heads and high points. The side edges of the lid (where the user would naturally grasp to open the lid) are devoid of laquer and have a high polish from years of use, as well as an overall wear haze.
|
