IMPROVEMENTS IN PERCENTAGE CALCULATORS
Year: 1884

page_text: WILLIAM SAVAGE MOORE of 240 Kennington Park Road Kennington in the
County of Surrey Gentleman do hereby declare the nature of my invention for
IMPROVEMENTS IN PERCENTAGE CALCULATORS" and in what manner the same is
to be performed, to be particularly described and ascertained in and by the following
statement, reference being had to the drawing hereunto annexed and to the letters
and figure marked thereon that is to say: -
This Invention relates to devices for reducing common fractions to decimals to be
used by railway and other transportation companies for determining percentages
and proportions in dividing rates revenues or expenses on the basis of mileage and
the Invention with these ends in view consists essentially of a plurality of graduated
scales and a suitable marking device or devices the novel construction of which will
be hereinafter described and claimed.
The drawing is a diagram of my improved calculator in which A indicates a
stationary triangle having a percentage scale B arranged along its hypotenuse; and
C is a similar triangle which is fitted to slide in triangle A and is likewise provided
with a scale D arranged along its hypotenuse which latter scale represents a series of
numbers the percentage of which is to be ascertained. The numbers in the scales B
and D increase in denomination from the right hand upward to the left hand the.
former extending from 0 to 100 and the latter from 0 to 1,000 or from 0 to any
number higher than 1,000 according to the value given to the graduations. If each.
graduation is made to count two instead of one the scale D will indicate 2,000 as
the highest number. I have shown the scale D marked off to indicate both 1,000
and 2,000 at the termination of the scale using two sets of numbers one the double
of the other to mark the graduations. When the scale D is moved against the
scale B the graduations of the two will exactly register with each other and the
percentage numbers will correspond with the numbers whose percentage of one
thousand or two thousand they (the former) represent. The movable triangle C is
provided with a slot E and the stationary triangle with a set screw F by means of
which it (the movable triangle) may be adjusted with respect to the stationary
triangle and held in any given position. The stationary triangle is provided at its
left hand side with a stretched cord G or equivalent device which serves as a marker
Pass 6.11

page_text: on the scale D. This cord is connected to set screws H I on the triangle and is
arranged at right angles to the base J of the stationary triangle. A second cord K
or equivalent device is attached to a collar L which is loosely mounted on a screw I
at the apex of the right angle of the stationary triangle and is connected at its
upper end by a set screw O to a slide P which move on a segmental bar Q the arc
of which is drawn from the pin or set screw I. One of the uses of the cord K is to
mark the percentage on the scale B and another use is to mark the numbers on both
scales as will be hereinafter explained.
The operation of the calculator is as follows If it is desired to ascertain what
is seventy per cent. of fourteen hundred the scale D is moved out from the scale B
until the cord G marks "1,400" on the upper edge of the scale D. The cord K is
then moved to a position to mark "70" on the lower edge of scale B in which
position it will also mark "980" on the upper edge of scale D as seventy per cent.
of fourteen hundred. The same position of the cords as shown in the drawing also
indicates 490 as seventy per cent. of seven hundred.
"
It is obvious from the above that if the percentage of several numbers aggregating
fourteen hundred is desired and 980 is one of these numbers the percentage will be
indicated by the cord K. In like manner the percentage which any part of fourteen
hundred bears to the whole will be indicated on scale by moving the cord K to a
position to mark that part of fourteen hundred on the scale D. Such is the
operation where an equal percentage is allowed to a given number of railroads for
example; but where an arbitrary" percentage is required by one of such roads
this percentage must be deducted and the remainder divided equally among the
remaining roads. In such case the cord K serves to mark the numbers on both
scales. For instance if one road requires thirty per cent. and the remaining seventy
per cent. is to be divided equally among the remainder of a given number of roads
the cord K is to be moved to a position in which it will mark 70 on scale B. Now
if the sum total in miles is twelve hundred and two hundred and twenty of these
belong to the road requiring thirty per cent. two hundred and twenty are to
be deducted from twelve hundred and the movable triangle is to be moved outward
until the remainder "980" is marked on scale D by cord K. Then if the cord K
is moved to positions to mark on scale D the respective numbers of miles of the
remaining roads whose sum total is nine hundred and eighty the several proportions
of seventy per cent. coming to the said remaining roads will be indicated on scale B
by cord K.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is:
1. In a percentage calculator the combination with a plurality of graduated scales
capable of adjustment with respect to each other of a suitable marker capable of
being moved to register with such scales the whole being arranged so as to ascertain
an arbitrary percentage substantially as described.
2. In a percentage calculator the combination with a plurality of graduated scales
capable of adjustment with respect to each other of stationary and movable
markers the latter capable of being moved to register with such scales and the
whole arranged so as to ascertain a given per cent. substantially as described.
3. In a percentage calculator the combination with a plurality of triangles
capable of adjustment with respect to each other and having respectively mileage
and percentage indicating scales of a movable marker capable of being moved to
register with such scales so as to ascertain an arbitrary percentage.
4. In a percentage calculator the combination with a plurality of triangles having
graduated scales on their hypotenuses of a marker capable of being moved to
register with such scales.
5. In a percentage calculator the combination with a plurality of triangles
Having graduated scales of stationary and movable markers the latter capable of
being made to register with such scales.

page_text: 6. In a percentage calculator the combination with a plurality of triangles having
graduated scales on their hypotenuses of stationary and movable markers the latter
capable of being made to register with such scales.
7. The combination of the stationary and the movable triangles having graduated
scales and numbers as described and the movable marker substantially as shown and
described.
8. The combination of the stationary and the movable triangles having graduated
scales and numbers as described and the movable marking-cord and segmental guide
for the same substantially as shown and described.
9. The combination of the stationary and the movable triangles having graduated
scales and numbers as described and the movable and stationary markers sub-
stantially as specified.
10. The combination with the triangles of the movable marking cord the loose
and pin for securing it at one end and the slide and segmental guide at the other
end substantially as shown and described.
11. The combination of the stationary triangle having the movable triangle
having a longitudinal slot in its base and the set screw for adjusting and bolding
said triangles in any desired relation to each other substantially as shown and
described.
12. The combination of the stationary triangle having the percentage scale B
arranged along its hypotenuse the movable triangle having the number-bearing
scale D arranged along its hypotenuse and the markers substantially as specified.
Dated this 19th day of September 1884.
WILLIAM S. MOORE,