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| Surveying Sighting "Sector" | Click on any image for a larger view. Scroll to view more items. |
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| LONG-ARM SURVEYING INSTRUMENT, French, c. early 19th century, signed "Brevet, J. Dartois." Made of brass with an integral walnut case, the assembly measures 25-1/4" (64 cm) overall. Two brass arms carry removable string sights, with removable string-and-slit eye sight at the vertex. One arm has clampable rotation about this center, with readout against a full circle degree scale. An adjustable and clampable segment is divided with scales of "Vernier" and "Déclinaison." The iron-reinforced base of the case has central thread for tripod mounting. The protective case cover is finely shaped to accommodate the sights. A most unusual instrument, in fine condition, by a maker not recorded in the standard references. (8242) $1450. |  |
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| Unusual Art Nouveau French Rule | Click on any image for a larger view. Scroll to view more items. |
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| ART NOUVEAU COMPENDIUM, French, c. 1900, signed "Henri Charles-Lavauzelle, Editeur Militaire, 10 rue Danton & 118 Bd. St. Germain, à Paris et à Limoges." This multipurpose "rule" is 7-1/4" (18 cm) long, made of shaped wood covered with printed and varnished paper, and set with magnifying lens, glazed compass, and calibrated opisometer for chart distances. Enhanced by beautiful Art Nouveau designs, the rule includes six metric chart reduction scales, a rectangular inclinometer (lacking plumb) with conversions to rise and fall, and tables for various French, Russian and English measures. In very fine condition, by an important late 19th / early 20th century publisher of military books and map. (7269) $350. | ||
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| Sir Howard Douglas Quadrant | Click on any image for a larger view. Scroll to view more items. |
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RARE PATENTED "REFLECTING SECTOR", English, c.1840, signed "A. Rofs & Co., 33 Regent St., London." Measuring 5-1/2" (14 cm) overall, this unusual sighting / plotting instrument is made of brass. It is a direct plotting third-circle, designed rather like a sextant, with peepsight, half-silvered "horizon" mirror, index mirror, divided degree scale engraved on brass, and vernier reading to one arcminute. However the index / plotting arm moves not only the index mirror and vernier, but also, through a sliding linkage, the peepsight and horizon mirror. As a result, one can make instantaneous sightings on objects as much as 120° apart, making this neither octant, nor sextant, nor quintant, nor quadrant, but sort of a direct plotting "tridant." The semicircular degree scale is connected to a 4" long linear plotting rule divided every ten units from 0 to 1000, with an interpolation grid divided every one unit. Condition is very fine, the brass retaining most of its original bright lacquer finish. |
| This instrument was the invention of Sir Howard Douglas of the Royal Military College at Farnham, as a combination of Hadley's quadrant and a protractor, enabling observed angles to be plotted directly, without having to read the angular scales. It is the first example of Douglas' instrument we have encountered by this maker, Andrew Ross & Co., in business under this name only from 1839 to 1842. (7289) $1850. |  |
| Defensive Dividers! | Click on any image for a larger view. Scroll to view more items. |
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WROUGHT IRON DIVIDERS / DAGGER, European 17th /18th century. Measuring 13-1/2" (34 cm) overall, this rather primitive pair of dividers is well constructed, with a five-leaf hinge with pommel knob, twin tapering arms, and double hilt. It has a good "heft" for use as a dagger. Condition is good, apparently all original, noting some pitting to the surface. The application of the hilt to dividers, making them into a significant close range weapon, is well documented. For example, one finds a rather formidable 16th century dagger / divider compendium in the Museo di storia della scienza in Florence, described by Bonelli and Settle. (7259) $2650. |
| Landmark Compass | Click on any image for a larger view. Scroll to view more items. |
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CARTOGRAPHIC POCKET COMPASS, Swiss, c. early 20th century, the 2-1/4" (5.7 cm) diameter plated brass case nicely glazed, and fitted with printed paper under its own protective glass disk, with a raised counterbalanced blued needle. The paper shows the pivot centered on a map of Switzerland, with cities, surrounding countries, and directionals all labeled in French, and with the map scale specified "Echelle 1:8,000,000." The center is in the region of the highest mountains of the Swiss Alps, and from there the compass serves as the tourist's panoramic guide to distant landmarks. Most unusual, and in excellent condition. (8222) $425. |
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