TESSERACT -- Antique Scientific Instruments -- Surveying and Drafting

EARLY ENGLISH GUNNER¹S CALIPERS, late 17th century, brass with steel points, 6-7/8" (17.5 cm) tall, distinctively designed with its boot-shaped feet for both inside (cannon bore) and outside (ball diameter) use. It is hand engraved with various scales and with charming cuffed-hand pointers on both sides. An inch scale along the opened edge is divided from 0 to 12 by tenths. For inside use, there are calibrations giving cannon abbreviation (for Falcon, Saker, Whole-Culverin, etc.) and bore diameter as a function of opening of the arms. For outside use there are circular scales for direct readout of the cannon ball diameter in inches, ball weight, appropriate cannon name, etc. Condition is fine noting light oxidation.

This is a very early English form. Weaver (1995) finds that it predates his four standard forms, and he located but one example, that by Richard Whitehead dated 1691 (the earliest known English gunner¹s calipers). We note also the rare signed transitional one with adjustable feet, Tesseract Catalogue 56, Item 29. (8345) $8500.

		THE "STERLING" CONVERTIBLE LEVEL, American, second quarter 20th century, signed "Warren-Knight Co., Philadelphia, U.S.A., Sterling, 3624, Patented Sept. 19, 1922." Standing 8" (20 cm) tall, and with a 13-1/4" (35 cm) long telescope (opening to 16-3/4" by racked focus and auxiliary sunshade), this sturdy instrument is made of brass with black enameled, natural, and plated finishes. The telescope, which focuses from about four feet to infinity, carries a long spirit level, and is removable from the horizontal wyes and mountable orthogonally, on hinged supports for the trunnions, to cover a limited range of elevation and depression. The base has an azimuthal scale divided every degree, with five-arcminute vernier, and has clamp, tangent screw, four-screw leveling system, and large internal thread for tripod. Condition is good with some wear, and a bend to the degree scale. Included is the original fitted case, rough from use.

Founded in 1912 by J. Henry Warren and Henry R. Knight, the company followed Izard-Warren, which in turn had followed Queen & Co., all with a history as important manufacturers of surveying instruments. The patent description states "Our present invention relates to a novel construction and arrangement of a convertible builder¹s level and transit... enabling the telescope to be supported at right angles to its normal position in trunnions or axles thus enabling the telescope to be elevated or depressed through an angle of at least 45° above and below the horizontal. It further comprehends a novel construction of telescope supports wherein novel means are employed for closing them and novel means are employed for effecting their rotary adjustment...." (8325) $850.

		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.


		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.

		UNUSUAL EARLY CALIPERS, Continental, c. 17th century, 3-1/2" (8.5 cm) tall, hand shaped of brass with finely applied curved iron legs. The calipers have three-leaf hinge, boldly cut geometric decoration on the brass, and stamped "pelican" maker's mark. The legs are shaped to measure outside dimensions of various solid shapes, e.g., gunnery balls. (8295) $750.