CALCULATING MACHINE."
Year: 1877

page_text: LETTERS PATENT to John Purvis Hawtrey, of Aldin House, Slough, in the
County of Buckingham, Schoolmaster, for the Invention of
CALCULATING MACHINE."
AN IMPROVED
Sealed the 5th March 1878, and dated the 14th November 1877.
PROVISIONAL SPECIFICATION left by the said John Purvis Hawtrey at
the Office of the Commissioners of Patents on the 14th November 1877.
JOHN PURVIS HAWTREY, of Aldin House, Slough, in the County of Buckingham,
Schoolmaster. "AN IMPROVED CALCULATING MACHINE."
The improvements consist in constructing the inachine with what I call an index
or scale, bearing a series of numbers placed in consecutive order from 0 upwards,
and in conjunction with such scale working or moving another series of like.
numbers in the reverse order to that in which those on the index are placed, on a
slide or roller, or any other contrivance by means of which said latter series of
numbers may be moved, as herein-after explained.
Also in furnishing the machine with a perforated plate, dial, or cover (which may
have on it the index engraved or otherwise marked) said perforations consisting of
a convenient slit for the passage of any pointed instrument intended to actuate the
second or moving series of numbers above described; also of one or more apertures
in the said plate or cover, for showing certain numbers of the moving series.
The various parts of the machine may be made of almost any material. I prefer
to construct the said machine box-fashioned, of an oblong shape, on plan, and of
sufficient depth to hold the moving series of numbers, which may conveniently be
marked on a band or tape, and wound on one or more rollers place inside, also
with a lid, moveable or otherwise, which shall have on its upper or outer surface
the index or scale conveniently placed in a column alongside of the perforated slit,
and one or more apertures made through which one or more of the moving numbers
in the machine may appear. The scale is marked with numbers, progressing
consécutively, say, from 0 to 9, or to any other number, but the moving or lower

page_text: from 0 to, say, 500, or any other number, said lower numbers being marked on a
band and placed on a roller in such fashion that they appear in consecutive order
at the aperture, when by means of a pointed instrument the said band is (through
the slit) drawn parallel to the scale.
The machine is to be use as follows:-Suppose it is required to add a column
of figures, say, 7, 8, 3, 2, 4, 6, the pointed instrument is placed opposite to zero, the
moving series are then drawn along the scale until the pointed instrument arrives
opposite 6 (or the last number of the given column) whereupon that number (6) of
the moving series appears at the aperture; then the style is again placed opposite
to zero and the moving series again actuated as in the first instance, but to 4 on the
scale, whereupon the number 10 or the sum of the two figures appears at the
aperture, and so on.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Purvis Hawtrey in the Great Seal Patent Office on the 14th
May 1878.
JOHN PURVIS HAWTREY, of Aldin House, Slough, in the County of Buckingham,
Schoolmaster. "AN IMPROVED CALCULATING MACHINE."
The improvements consist in constructing the machine with what I call an index
or scale, bearing a series of fixed numbers placed in consecutive order from 0
upwards, and in conjunction with such index working or moving another and
moveable series of numbers, placed on a band or ribbon in the same or in the
reverse order to that in which those on the index are placed, on or in a slide, or on
rollers, or any other contrivance by means of which said moveable series of numbers
may be moved, as herein-after explained.
Also in furnishing the machine with a perforated plate, dial, or cover, having on
it the index engraved, printed, or otherwise marked one set of perforations, con-
sisting of convenient slits or openings for the passage of any instrument, pointed
or otherwise, intended to actuate the second or moving series of numbers above
described, or the moving series may be actuated by hand simply, and other per-
forations to form apertures in the said plate or cover for showing certain numbers
of the moving series.
The various parts of the machine may be made of almost any material, and it
can be fashioned of any shape on plan, and of sufficient depth to hold the moving
series of numbers, which can conveniently be marked or printed on a band or tape
of paper, linen, metal, or any other material, which may be wound on one or more
rollers placed inside; also with a lid, moveable or otherwise, which shall have on
its surface the index or scale conveniently placed alongside of the perforated slits or
openings, and one or more apertures made through which one or more numbers of
the moving series may appear. The index is to be marked with numbers, pro-
gressing consecutively, say, from 0 to 10, or to any other number or numbers, and

page_text: the moving series from 0 to any other number or numbers, said moving series of
numbers being placed in such fashion that they may appear in consecutive order
at the aperture or apertures when the said moving series are drawn parallel to the
index.
The machine is to be used as follows:-Suppose it is required to add a column
of figures 7, 8, 3, 2, 4, 6; in the case where the numbers on the index are in reverse
order to the numbers on the moving series the pointed instrument (when one is
used) is placed opposite to zero on the fixed scale, the moving series are then drawn
along the index until the pointed instrument arrives opposite 6 (or the last number
of the given column) whereupon that number (6) of the moving series appears at
one of the apertures; then the moving series are again actuated from zero to 4 on
the scale, whereupon the number 10 or the sum of the two figures appears at the
aperture, and so on, until the figure 7 has been reached, when the sum total of the
figures, viz., 30, will appear at the aperture.
In the case where the numbers on the index are in the same order as the moving
series the instrument (when one is used) is placed opposite to the number 6 on the
index, and the moving series actuated, as above described, until the instrument
arrives at zero, whereupon the number (6) of the moving series appears at one of
the apertures, then the moving series are again actuated from 4 to zero on the
index, whereupon the number 10 or the sum of the two figures appears at the
aperture, and so on,Juntil the figure 7 has been reached, when the sum total, viz., 30,
appears at the aperture.
The machine also applies to the addition of pounds, shillings, and pence, by
placing shillings, pence, and fractions, or other compound quantities in separate
columns on the moving band.
The accompanying Drawing will serve to illustrate a convenient mode of per-
forming the Invention as applied to simple quantities, where Figure 1 is a plan or
elevation, and Figure 2, section of the machine.
a, is the fixed index; b, longitudinal slit for pointed instrument; c, d, rollers;
e, aperture; f, tape or band.
From what has been said before the use of the machine is obvious.
In witness whereof, I, the said John Purvis Hawtrey, have hereunto set my
hand and seal, this Fourteenth day of May, in the year of our Lord One
thousand eight hundred and seventy-eight.
JOHN DIID VISITADTD DV
JOHN PURVIS HAWTREV (L.B.)