Democratic Sentinel, Volume 6, Number 6, Rensselaer, Jasper County, 10 March 1882 — A. Curious Scientific Instrument. [ARTICLE]

A. Curious Scientific Instrument.

A New York papa: mentions a onrious instrument invented by a young Japanese engineer. It is a familiar fact to those acquainted with the problems of surveying and engneering, that the most tedious calculations associated with professional services of that class arise from the method of triangulation now in use, and from the fatiguing and abstruse relations of sines and cosines which enter into the work. The necessity of an instrument capable of measuring these relations with aocuracy and of experimentally solving the problems of trigonometry arhing in the course of a survey, has been long confessed by engineers. The invention perfected by the young Japanese engineer—not patented, by the wav—consists primarily of a steel or brass plate, near the bottom of which is a graduated bar which may represent the base of any given triangle. The bar is graduated into ten equal parts with extreme accuracy, and these sections are again graduated until a linear register of the utmost conceivable fineness is produced. At one end of the bar is fixed a semicircular plate, the c.rcumference of which is graduated into degrees, minutes, and seconds, and the base of which is parallel with the bar itself. At the other end is placed a quadrant, or quarter of a circle, graduated in the same manner. At the center of each of the oiroles of which these plates form sections, a movable bar turns upon a pivot, in the same manner as the hands of a clock. Each of these bars is graduated into ten equal parts of the same length as those of the bases, and each part is finely subdivided. The quadrant and semicircular plates are also so constructed as to slide into the fixed bar, thus forming a baae-line of any convenient or assignable length. With this instrument such problems as those in which one angle and the adjacent sides, one Bide and the adjaoent angles, or one angle and the opposite side are given, to find the other factors, may be performed instantaneously without calculation. Having for example, one angle and the adjaoent sides given, the engineer revolves the graduated har upon the quadrant if the angle is less than a right angle, and upon the semicircle if it is obtuse, until the proper angle is registered. He then revolves the second bar until a triangle is formed whose sides are exactly proportionate to those given, and reads off the second angle from the plate. To find the third it is only necessary to subtract the sum of the two already ascertained from 180. In the meantime, the ratio of the third side to the other has already been registered upon the seoond movable bar. The problem is consequently solved without reference to the sines, cosines, and tedious logarithms with which trigonometry abounus.