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SCIENCE 



[Entered at the Post-Offlce of New York, N.Y., as Second-Class Matter.] 



A WEEKLY NEWSPAPER OF ALL THE ARTS AND SCIENCES. 



Sevknth Year. 

 Vol. XIV. No. 348. 



NEW YORK, October 4, iJ 



Single Copies, Ten Cents. 

 ^3.50 Per Year, in Advance. 



THE PROPORTIOR. 

 A NOVEL and exceedingly simple form of calculating-machine, 

 called by its inventor a " proportior," is being brought to the at- 

 tention of accountants, statisticians, and others, in this city. The 

 general appearance of the device is shown by the accompanying 

 engravings. Fig. i shows the instrument on its revolving stand, 

 Fig. 2 indicates the first position in solving problems, and Fig. 3 

 the second position. The magnifier, by which the operator is able 

 to read the divisions of the disk with accuracy, is clearly shown in 



Referring to Fig. i, it will be seen that the outer circle rotates 

 around the inner disk. The relation of the parts is perhaps better 

 shown in Figs. 2 and 3, which are on a larger scale. Stops are 

 provided by which the disk may be fastened to the outer circle at 

 any desired point. The frame that supports the disk and circle is 

 of metal, the disk and ring being of wood, constructed to overcome 

 expansion and contraction, and on which is affixed the scales. 

 The other parts consist of an outer ring, a runner or guide, a cap, 

 two set-screws, and two brakes. The metal frame supports and 

 holds all the other parts. The movements are adjusted to a true 

 centre. The inner disk and the outer ring contain the figures and 

 lines by which computations are made. The runner or guide, 

 which carries the magnifying-glass, is of assistance in locating 

 numbers and lines, and in bringing those on the one scale in line 

 with those on the other, so that results may be quickly obtained 

 and read. The cap acts as a set-screw to the arm, holding it 

 firmly whenever it is required to be so held. The two set-screws 

 on the outside actuate two brakes, which form part of and are 

 located under the outer ring. By them the outer circle is locked or 

 unlocked from the inner disk. When locked, the disk and ring are 

 converted into a table of calculations. The magnifier covers the 



FIGS. I AND 2. — THE PROPORTIOR. 



the two latter figures, the reader being supposed to be looking 

 toward the operator. This calculating-machine, the scale part of 

 which is but fifteen inches in diameter, may be described as a slide 

 rule of greatly extended length, reduced to a small circle. In the 

 language of the inventor, it is a mechanical device which performs 

 with ease, rapidity, and correctness, operations in commercial and 

 mechanical arithmetic. It is further asserted to be an arithmetical 

 library in itself, in which, for the purpose of computation, the unit 

 can be divided into 1,000,000 parts, while the whole numbers range 

 from I to 1,000,000. 



entire width of both scales, and is an important assistant to the 

 sight in reading the finer divisions. It is mounted upon the runner, 

 and is adjustable. 



The operation is as follows. The instrument being set on a 

 suitable surface, and at a convenient height so that the eyes can 

 be directly over it, the caps and set-screws are loosened, so that the 

 runner is free to move and the circle to revolve around the disk. 

 The operator then assumes the position shown in Fig. 2, and exercises 

 JQst force enough to hold the entire apparatus steady. His right 

 hand grasps the edge of the outer ring, moving it either to or from 



