US736481A - Mathematical device. - Google Patents

Description

No. 736,481. a PATENTED AUG. 18, 1903. s. N. BETTS. MATEEMATIGAL DEVICE.

l11131 L10AT111E FILED 1111.5. 1903.

No MODEL.

,fly 1,

UNITED STATES rammed August 1e, 19ers.

PATENT OFFICE.

MATH EMATICAL D.Ev|oE.

SPECIFICATION forming part of Letters Patent No. 736,481, dated August 18, 1903. Application filed January 5. 1903. Serial Fo. 18 7,984. (No modeld T all whom it may concern.-

Be it known that I, STEPHEN N. BETTs, of the cityV of Hillsdale, in the county of Hillsdale and State of Michigan, have invented a new and useful device which I call the Supervisors Assistant, of which the following is a specification.

'This invention relates to an improved mathematical instrument especially designed to assist supervisors in making out or extending their assessment-rolls, and has for its object to provide a simple, inexpensive, and eflicient device of this character by means of which State; county, and town taxes may be quickly and accurately obtained on individual valuations.

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In the accompanying drawings, Figure 1 .is

a top plan view of my improved mathematicaly In the accompanying drawings, A will b ereferred to as the xed part, andB, B', B", and B as the rotatable disks or circles. The disks B, B', B", and B'" are rotatably' mounted on a pin or bolt D, secured in any suitable manner to the fixed part A, and encircling the bolt D andresting on the Adisk B"' is a grooved collar or eyelet E, loosely mounted in an arm or pointer C, a clamping-nut F engaging the threaded end of the bolt D and holding the several parts together. By having the arm C loosely mounted on the eyelet E said arm is free to revolve when the clamping-nut is tightened, while the disks remain relatively iixed, thereby permitting said arm to be swung to any position on the face of the instrument and in alinement with any desired series of graduations en the disks and xed part A, so that'the results may be easily read. The figures on the xedpart A and revolving disks are logarithmically arranged according to the law ot' decimal notation and are relatively alike, varying only by being a little closer together as the diameter of the disks diminish, the large figures 1, 2, 3, &c., upto 10occ urring in regular order with varying spacesbetween them and exactly coveringthe circuit of the disksor circles. The spaces between the lines decrease in logarithmic ratio, the space from l to 2 being exactly the same as from 2 to 4 or from 4 to 8, and so on in the same geometrical ratio.

In extending the assessment-rollv we consider the figures on the fixed part Aas multiplicand's and those on the disks or circles products. opposite to the figure l on the fixed part is the multiplier, no matter what that number may be, and each number on the fixed part is multiplied by that number and the product indicatedl on the circle or disk directly opposite. In dividing, place the divisor found on the disk opposite the numeral The figure on the circle or disk- 1 on the fixed part.' Then find the divil dend on the disk, and opposite to it on the fixed part 'will be found the quotient.

The operation of the instrument is as fol` lows: To'ext'end the assessment-roll, three. disks or circlesl are used in order to obtain. the State, county, and town tax at the samev tax on the dollar for the township on the disk B", which we Will suppose to be .00865, and also place it opposite the numeral .1 on the fixed part. After'the above ratio on each disk has been arranged opposite the numeral 1 on the fixed part the clamping-nut F is tightened, which securely holds the several disks in position, the arm C, however, being free to revolve in the eyelet D. The taxon" any individual valuation may now be obtained by sliding the arm C on the pivot D to the numeral on the fixed part representing said valuatiomwhen the State', county, and town tax may be easily read ou the disks B, B', andB", respectively.- For instance, if the valuation is eleven hundred dollars we slide the arm C toa position in line with the graduation 11, (which we now call eleven hundred,) and by reading across the-circles or disks we nd the State tax to be ten dol' lars and twenty-nine cents, the county tax four dollars and ninety cents, and the town tax nine dollars and fifty-two cents. valuation found on the fixed part the tax on For any that particular valuation will be found on the cnlating-tables, a grooved collar slidably circle or disk opposite. mounted on the pin and befftring.;` against the Having thus described the invention, what disks, au arm loosely mounted in the groove I claim, and desire to secure by Letters Paton said collarandanut engaging the threaded end of the pin and adapted to clamp the col- 15 5 ent, is

In a mathematical instrument the combilar on the disks independently of the arm. `nation with a frame, of a pin provided with STEPHEN N. BETTS.

terminal threads secured to the frame, a plu- Witnesses: ral-ity of concentric disks rotatably` mounted JACOB W. PAENNS, lo on the pin, said frame and disks bearing cal- MARTIN WILLMAN.

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