Improvements in Calculating Appliances.
Year: 1891

page_text: Date of Application, 9th Oct., 1891-Accepted, 14th Nov., 1891
COMPLETE DIEUIFICATION,
Improvements in Calculating Appliances.
I, EDWARD DE LANOY LITTLE, of The Mount, Northallerton, Master of
Arts, do hereby declare the nature of my invention for IMPROVEMENTS IN
CALCULATING APPLIANCES and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:-
The object of the present invention is to effect mechanically, without mental
effort, and without resort to printed tables, the mutual conversion of alternate
scales. or systems of measurement, as for instance of weights and measures as.
expressed in the English and French systems respectively.
The apparatus consists of two equal semicircular plates or cards, marked A and B.
respectively in the accompanying drawing, hinged together at one extremity (C in
drawing) of their diameters, each of which diameters carries a similar scale divided
into one hundred, or any other convenient number of equal spaces.
From the same
extremity, C, of the scale on the lower plate are marked off along the scale various.
lengths CD, CE- --, each of which has a ratio to the total length of the scale
inverse to the ratio which an unit of the weight, measure, or other dimension
represented by the length has to an unit of the corresponding weight, measure, or
dimension in the alternate system. These various lengths CD, CE,
taken as diameters, and upon them are described semicircular arcs, bearing the
names of the various weights, measures, or dimensions, which they severally
represent, and along the arc of a semicircle described upon the whole scale as
diameter are printed, in the same order as the above mentioned names, the names.
of the corresponding weights, measures, or dimensions into which the former are to
be converted.
The instrument is used in the following manner :-
--
are
The upper plate is turned on the hinge C until that division of its scale which
indicates the number of units of weight, measure, or dimension to be converted,
stands exactly on the arc of the lower plate which bears the name of the weight,
measure, or dimension in question. The number of units of weight, measure, or
dimension after conversion, will be read at that division of the scale of the upper
plate which stands exactly on or nearest to the arc bearing the name of the weight,
measure, or dimension into which the original quantity is to be converted.
If, for instance, it is required to convert 63 kilomètres into miles, the upper plate-
is turned, as shown in the drawing, until the 63rd division of its scale stands on the
arc I of the lower plate which is marked 'kilomètres,' and, on looking to the arc E
marked 'miles,' the 39th division of the scale is seen to fall a little short of the
arc. Estimating the deficiency at one tenth and one half-tenth of a division, the
required conversion will be 39-15 miles, which is approximately correct.
Where greater accuracy is required, a vernier scale may be attached to the scale
of the upper plate.
The drawing illustrates the application of the invention to the English and
French systems of measures of length, area, and weight only, but it is equally
applicable to any varying systems of measurement of like magnitudes.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In an apparatus such as described an upper and a lower semicircular plate
hinged together at one extremity of their diameters.

page_text: 2. In apparatus such as described the arrangement on one plate of a scale, and
on the other of various semicircular arcs in such a way that a single scale serves
for the mutual conversion of varying systems of measurement of like magnitudes,
without mental effort, and without resort to the usual tables of conversion.
Dated this 8th day of October 1801.
EDWARD DE LANOY LITTLE.