IMPROVEMENTS IN APPARATUS FOR ASCERTAINING AND INDICATING THE NUMBER OF DAYS BETWEEN TWO DATES
Year: 1879

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
"
& Co., Patent Agents, Southampton Buildings, London, for the Invention of
IMPROVEMENTS IN APPARATUS FOR ASCERTAINING AND INDICATING THE
NUMBER OF DAYS BETWEEN TWO DATES." A communication from abroad by
Casimir Louis Chambon, of Paris, France.
Senlod the 6th April 1880, and dated the 11th October 1879.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 11th October 1879.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN APPARATUS FOR ASCER-
TAINING AND INDICATING THE NUMBER OF DAYS BETWEEN Two DATES." [A
communication from abroad by Casimir Louis Chambon, of Paris, France.]
This Invention relates to improvements in calculating apparatus for ascertaining
expeditiously and with precision the number of days which have transpired or
intervened between any two dates whatsoever, either of a period of three hundred
and sixty days or a year of three hundred and sixty five days.
The said improvements are based essentially upon the combination of a series of
fixed or movable tablets or tables provided with the numbers from 1 to 360
suitably arranged, and a series of fixed or movable plates or pieces having indica-
tions upon them of the months of the year, or the numbers from 1 to 30.
By changing the position of these tablets or pieces with regard to each other the
number of days which intervene between any two dates, whether in the same year
or in two consecutive years, may be ascertained immediately.
I will now proceed to describe the various forms of my improved apparatus for
effecting the above named objects, that is to say, in the first arrangement I employ
a series of fixed and movable pieces of pasteboard, wood, ivory, metal, or other
suitable material.
According to the second arrangement of my improved apparatus the numbers
are arranged upon rollers in such a manner as to occupy less space than the
arrangement above described, and also facilitate the perusal of such numbers.
Prins S31

page_text: The third arrangement is similar to that last hereinabove described, and is
arranged in such a manner as to constitute an elegant and commodious piece of
furniture.
I will now proceed to describe the first arrangement of my improved apparatus,
which is the most simple of the various arrangements, although the same is not so
commodious for use, that is to say, the said apparatus is composed of a sheet of
cardboard provided upon twelve horizontal lines with all the numbers from 1 to 360,
separated into thirty vertical columns; upon the first line the numbers from 1 to
30 are arranged, upon the second the numbers from 31 to 60, and so on.
A movable sliding piece or plate provided with two consecutive lists of tho
twelve months of the year is so arranged that it can be placed opposite the said
table in such a manner that one or the other of the names or indications of the
various months will be opposite to one or the other of the aforesaid horizontal lines
of figures, as desired.
Above the said table I arrange a second movable plate or piece having the
indications from 16 to 30, 1 to 30, and 1 to 15 upon the same, so that any one of
the said figures may be brought to a position above any desired column or vertical
row on the aforesaid table.
In order to facilitate the employment of the said apparatus the division of the
said sliding plate with the figure 1 upon it is colored blue, and the division with
the figure 30 upon it is colored red.
Under these circumstances it is very easy to ascertain, for example, the number
of days which have transpired or intervene between the 1st July and the 27th
November, that is to say, I bring the blue division (provided with the figure 1) of
the upper movable plate above the blank space preceding the first row of figures on
the sheet of cardboard. I then move the movable sliding plate having the indica-
tions of the months of the year upon it into such a position that the month of July
is in a direct line with the first or top horizontal row of figures upon the cardboard
plate. Upon the horizontal line corresponding or opposite November, and in the
vertical column of figures corresponding with the division 27 of the upper movable
plate or piece, the indication desired will now be found, that is to say, the
number 146.
I would remark, however, that the first day, that is to say, the 1st July, is not
included in the number found, that is to say, 146, but if it should be desired to
include such first day it is simply necessary to place the red division of the sliding
plate carrying the number 30 above the aforesaid blank space preceding the first
vertical line of figures on the cardboard plate, and the number 147 will then be
found in the vertical column upon the same, below the division numbered 27,
instead of the number 146, that is to say, the first day will then be included.
If the two dates at the commencement and end of a period to be reckoned are
the same, as, for example, if it is desired to ascertain the number of days from the
1st July to the 1st November, the operation is the same,with the exception that it
is then necessary to "skip" a month, that is to say, to raise the movable plate
provided with the indications of the months to the extent of one division on the
cardboard, and then look for the answer in the vertical column of figures on the
latter, below the second blue division (having the figure 1 upon it) on the aforesaid
sliding plate or piece. The number 120 will thus be found, which is the number
desired, that is to say, the number of days between the 1st July and the 1st
November. If the last date of any period is a smaller number than the first date
of such period, that is to say, for instance, if it is desired to ascertain the number
of days between the 27th July and the 3rd November, the upper sliding plate is so
moved that the figure 27 will be above the first vertical column of figures on the
cardboard plate. I then look for the answer in the vertical column of figures then
situated below the division 3 of the upper sliding plate, where is found the
number 127. In this number, however, both the first and last day of the period
are included. If however, as is generally the case, it is not desired to include the
first day of the period, it is then necessary to place the division 27 upon the upper

page_text: movable sliding plate above the aforesaid blank space preceding the first vertical
column of figures on the cardboard, instead of above the said first column, and the
number 126 will then be found instead of 127.
The second arrangement of my improved apparatus constructed according to this
Invention acts in precisely the same manner as that above described, but in order to
facilitate the employment of the said apparatus the movable plates are replaced by
bands mounted upon rollers, which may be manipulated from the exterior of the
apparatus by means of two suitably arranged buttons or knobs. The date roller
is provided with 30 divisions upon it, carrying respectively the numbers from
1 to 30.
The only difference between this form of apparatus and the one above described
is that the tablet containing the number of days is also mounted upon a roll, the
axis of which is in line with that of the roller which carries the list of months;
these two rollers, which in their normal progress turn together, may be rendered
independent of each other, when desired, by pressing upon one of the aforesaid
knobs. I can thus bring the tablet or table into such a position so as to present
its red starting line 1, 2, 3, .
30, whatever the first month of the period may
be, and I then operate the same as before, causing the list of months and the table
of days to turn together until the last month of the period appears in front of the
window or opening of the apparatus.
- 30.. The
I will now proceed to describe the third arrangement of my Invention, which is
a more complete apparatus for calculating the number of days between two dates,
and which arranged similarly to that above described, with the exception that
the table or tablet of numbers is arranged upon a vertical drum or barrel which
can turn independently of the drum carrying the numbers 1, 2, 3, -
said apparatus is provided with an operating button, which when pressed down
causes the two drums or rolls to work conjointly with each other and together.
The action of the said apparatus is the same as in the first case; the red starting
column is provided with the numbers from 30 to 360, and a column containing the
numbers from 1 to 331 is colored blue; in this manner the last day of the period
may be reckoned or not.
The engagement of the two drums or rolls is effected by means of pins or catches
fixed upon the upper roller carrying the figures 1 to 30, and engaging or entering
notches or holes in the lower roller carrying the numbers.
In order that the figures on the upper roller and the columns of figures on the
lower roller may stop properly in front of the windows or openings in the apparatus,
I sometimes employ toothed wheels, the teeth of which admit pawls or projections
which only permit the said wheels to move one tooth at a time.
The front of the apparatus is also provided with a table which indicates
immediately the number of days which it is necessary to add or subtract to pass
from a period of 360 days to the year of 365 days.
The said apparatus may be arranged upon a table in an inclined position,
thereby facilitating the inspection of the various tables or indications upon the
same.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the
10th April 1880.
"
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. IMPROVEMENTS IN APPARATUS FOR ASCER-
TAINING AND INDICATING THE NUMBER OF DAYS BETWEEN Two DATES."
communication from abroad by Casimir Louis Chambon, of Paris, France.
A
This Invention relates to improvements in calculating apparatus for ascertaining
expeditiously and with precision the number of days which have transpired or
intervened between any two dates whatsoever, either of the fiscal year of three
hundred and sixty days or a civil year of three hundred and sixty five days.
The said improvements are based essentially upon the combination of a series of
fixed or movable tablets or tables provided with the numbers from 1 to 360 suitably
arranged, and a series of fixed or movable plates or tablets having indications upon
thein of the months of the year, or the numbers from 1 to 30.
By suitably changing the position of these tablets or tables with regard to each
other the number of days which intervene between any two dates, whether in the
same year or in two consecutive years, may be ascertained immediately.
In order to enable the construction of my improved apparatus to be more clearly
understood I have represented in the accompanying Drawing three different
methods of carrying my Invention into practice. According to the first method,
which is illustrated in front view in Figure 1 of the Drawing, I merely employ a
series of fixed and movable pieces of paste-board, wood, ivory, metal, or other
suitable material.
According to the second arrangement of my improved apparatus the numbers
are arranged upon rollers in such a manner as to occupy less space than the
arrangement above described, and also facilitate the perusal of such numbers, as
shewn in perspective in Figure 2 of the Drawing.
The third arrangement of my improved apparatus, which is represented in
Figures 3 to 9 of the accompanying Drawing, is similar to that last hereinbefore
referred to, and is arranged in such a manner as to constitute an elegant and
commodious pieco of furniture. In these Figures, Figure 3 is a perspective view,
and Figures 4 and 5 are elevations partly in section; Figure 6 is an underside
view, and Figures 7, 8, and 9 are plans of various parts of the said apparatus.
I will now proceed to describe the first arrangement of my improved apparatus,
which is the most simple, and which, although not very convenient for use, permita
my improved system to be clearly understood.
The said apparatus, as shewn in Figure 1 of the Drawing, is composed of a sheet
of cardboard a provided upon twelve horizontal lines with all the numbers from 1
to 360, separated into thirty vertical columns; upon the first line the numbers from
1 to 30 are arranged, upon the second the numbers from 31 to 60, and so on.
A moveable sliding rule or plate b provided with two consecutive lists of the
twelve months of the year is so arranged with regard to the table a that it can be
adjusted to bring one or the other of the names or indications of the various
months opposite to one or the other of the aforesaid twelve horizontal lines of
figures, as desired.
Above the said table a I arrange a second movable plate or slide rule having
the numbers from 16 to 30, 1 to 30, and 1 to 15 upon the same, so that any
one of the said figures may be brought to a position above any desired column
or vertical row of figures on the table a.
In order to facilitate the employment of the said apparatus the division of the
said sliding plate with the figure 1 upon it is colored blue, and the division with the
figure 30 upon it is colored red.

page_text: Under these circumstances it is very easy to ascertain, for example, the number
of days which have transpired or intervened between the 1st July and the 27th
November. For this purpose I place the blue division (provided with the figure 1)
of the upper movable plate o above the arrow at the commencement of the tablet;
I then move the vertical sliding plate b into such a position that the month of
July is in a direct line with the first horizontal row of figures upon the plate a.
Upon the horizontal line corresponding or opposite to November, and in the vertical
column of figures corresponding with the division 27 of the upper movable rule c,
the indication desired will then be found, that is to say, the number 146.
I would remark, however, that the first day, that is to say, the 1st July, is not
included in the number found, namely, 146, but if it should be desired to
include such first day it is simply necessary to place the red division of the sliding
plate provided with the number 30 above the aforesaid arrow on the plate, and the
number 147 will then be found in the vertical column upon the sanie, below the
division of the rule a numbered 27, instead of the number 146, that is to say, the
first day will then be included.
If the two dates at the commencement and end of a period to be reckoned are
the same, as for example, if it is desired to ascertain the number of days which
transpire between the 1st July and the 1st November, the operation is the same,
with the exception that it is then necessary to omit or ignore a month, or, in other
words, to raise the movable plate b provided with the indications of the months
one line, that is to say, to raise the month of November to the extent of one
division, and then look for the answer in the vertical column of figures below the
second blue division (also having the figure upon it) on the aforesaid sliding
plate or rule c. The number 120 will thus be found, which is the number desired,
that is to say, the number of days which elapse between the 1st July and the
1st November. If the last day of any period is represented by a smaller number
than the first day of such period, that is to say, for instance, if it is desired to
ascertain the number of days which elapse between the 27th July and the
3rd December, the upper sliding plate is so moved that the figure 27 will be above
the first vertical column of figures (containing the figures 1, 31, 61, 91, and so on)
of the plate a. I then raise the plate b to the extent of one division in a similar
manner to that above described, and look for the answer in the vertical column of
figures then situated below the division 3 of the upper sliding plate, where is found
the number 127. In this number, however, both the first and last day of the
period are included. If however, as is generally the case, it is not desired to include
the first day of the period, it is then necessary to place the division 27 upon the
upper movable sliding plate above the aforesaid arrow on the space preceding the
first vertical column of figures on the cardboard, instead of above the said first
column, and the number 126 will then be found as the answer instead of 127.
The second arrangement of my improved calculating apparatus, which is shewn
in Figure 2 of the Drawing, operates in substantially the same manner as that
above described, but in order to facilitate the employment of the said apparatus the
movable rules or slides are replaced by bands mounted upon rollers, which may be
manipulated from the exterior of the apparatus by means of two conveniently
arranged buttons or knobs d, e. The date-roller is provided with 30 divisions
upon it, carrying respectively the numbers from 1 to 30.
The only difference between this form of apparatus and the one above described
is that the tablet a containing the number of days is also mounted upon a roller,
the axis of which is in line with that of the roller which carries the list of months;
these two rollers, which in their normal action are united and turned together, may
be rendered independent of each other, when desired, by means of the knob e. I
can thus bring the tablet or table into such a position as to present its red
starting line 1, 2, 3, --- 30, whatever the first month of the period may be, and I
then operate the same as before, causing the list of months and the table of days to
turn together until the last month of the period appears in front of the window or
opening of the apparatus.

page_text: I will now proceed to describe the third arrangement of my Invention, as
illustrated in Figures 3, 4, 5, 6, 7, 8, and 9 of the Drawing, which shew a more
complete apparatus for calculating the number of days between two dates, and
which is arranged similarly to that above described, with the exception that the
table or tablet a is arranged upon a vertical drum or barrel which can turn
independently of the drum c carrying the numbers from 1 to 30, as will be seen by
reference to Figure 5. f represents an operating button, by means of which the
two drums or rolls can be caused to work conjointly with each other and turn
together, as shewn in Figure 4. The action of the said apparatus is the same as in
the first case; the red starting column is provided with the numbers from 30 to
360, and the column containing the numbers from 1 to 331 is colored blue, so that
the last day of the period may be reckoned or not, as above described.
The coupling of the two drums or rolls is effected by means of the pins or
catches g, Figures 5 and 6, fixed upon the roller c, and arranged to engage with or
enter notches or holes in the roller a, shewn in Figure 7.
In order that the figures on the roller c and the columns of figures on the drum
or roller a may stop properly in front of the windows or openings in the apparatus,
I sometimes employ star-wheels h, k (Figures 8 and 9), the teeth of which admit
pawls or projections which provent the said wheels from moving the distance of
more than one tooth at a time.
The front of the apparatus is also provided with a table which indicates at once
the number of days which it is necessary to add or subtract in passing or changing
from the fiscal year of 360 days to the common civil year of 365 days.
The said apparatus may be arranged upon a table in an inclined position, as
shewn side elevation in Figure 10, thereby facilitating the inspection and perusal
of the various tables or indications upon the same.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,-
An apparatus for ascertaining and indicating the number of days which transpire
or intervene between any two dates, either of the fiscal year of three hundred and
sixty days or of the civil year of three hundred and sixty five days, as above
described and as shewn in the accompanying Drawing.
Also in an apparatus for ascertaining and indicating the number of days between
two dates, the combination of three fixed or movable tablets or tables, the first of
which carries the numbers from 1 to 360 divided into 12 lines and 30 columns, the
second the numbers from 1 to 30, and the third the list of the months, the said
tablets or tables being so arranged as to constitute a single apparatus, and being
capable of adjustment with regard to each other, either conjointly or separately,
either by a sliding movement if applied to flat surfaces, or by a circular movement
if attached to rollers, in the manner above set forth, and as represented in the
accompanying Drawing.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Tenth day of April, in the year of our Lord One
thousand eight hundred and eighty.