April 24, 2024
Antique Unmarked Folding White Sector Calculating, Mathematical Rule, 6" Long
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Here we have an Antique Unmarked Folding White Sector Calculating, Mathematical Rule, 6" Long. The sector, also known as a proportional compass or military compass, was a major calculating instrument in use from the end of the sixteenth century until the nineteenth century. It is an instrument consisting of two rulers of equal length joined by a hinge. A number of scales are inscribed upon the instrument which facilitate various mathematical calculations. It was used for solving problems in proportion, trigonometry, multiplication and division, and for various functions, such as squares and cube roots. Its several scales permitted easy and direct solutions of problems in gunnery, surveying and navigation.The overall condition of the White rule and the Brass hinge, is EXCELLENT with a nice even coloration and only minor amount of fine scratches here and there. All of the graduations and numbers are strong and dark including graduations on the narrow edges. The hinge works as it should. Both of the alignment pins are present. The legs line up as they should. No owners marks.** Please remember to leave Feedback . I will gladly reciprocate. :-)
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