Referring to the illustration, Fig. 1, of Pascal’s machine on the
opposite page, it will be noted that there are a series of square
openings in the top of the casing; under these openings are drums, each
numbered on its cylindrical surface.
[Sidenote: _Description of Pascal’s invention_]
As the machine illustrated was made to figure English currency, the two
right-hand wheels are numbered for pence and shillings, while the six
wheels to the left are numbered from 1 to 9 and 0 for pounds.
[Illustration: Blaise Pascal]
The pounds register-drums, or numeral wheels, are each operated by a
train of gearing connecting them with a ten-armed turnstile wheel which
form the hub and spokes of what appears to be a series of wheels on the
top of the casing. While the spokes and hub are movable, the rims of
these wheels are stationary and are numbered from 1 to 9 and 0.
The geared relation between the turnstile wheels and the numeral wheels
is such that rotating a turnstile will give like rotation to its
numeral wheel.
Assuming that the numeral wheel of any one of the different orders
registered 0 through its sight opening and the turnstile of the same
order was moved one spoke of a rotation, it would move the wheel so
that the 0 would disappear and the figure 1 would appear; now if we
should move the same turnstile three more spokes the numeral wheel
would move likewise three spaces and the 4 would appear.
A stop in the form of a finger reaching over the spokes is provided
to stop the turnstile at the right point so that the figures on the
numeral wheels may register properly with the sight openings in the
casing.
[Sidenote: _Constructional features of the Pascal machine_]
The figures on the wheel rims fast to the casing are arranged
anti-clockwise to register with the space between the spokes, the 0
registering with the first space, the 1 with the second space and so
on around the wheel. Thus by use of the finger or a stylo inserted in
a space opposite the number to be added, the operator may move the
spoked wheel or turnstile clockwise until stopped by the stop finger.
By repeated selection and operation for each figure to be added, the
wheels will be revolved through their cycles of rotation caused by the
accumulation.
As the numeral wheels complete each rotation the 0 will appear, so
that a registration of the tens must be made. Pascal provided for the
accumulation of the tens by automatically turning the wheel of next
higher order one point through the action of the lower wheel.
The novel means employed for this transfer of the tens consisted of
a one-step ratchet device operated by a pin in the train of gearing
connected with the lower numeral wheel, which, as the lower wheel
passed from 9 to 0, forced the lever to which the ratchet pawl was
attached in a direction to cause the gearing of the higher numeral
wheel to be ratcheted forward far enough to add one to the higher
numeral wheel.
The direct actuation of a numbered wheel through its various degrees of
rotation and the secondary feature of effecting a one-step movement to
the numbered wheel of higher order (which seems to have been originated
by Pascal) is the foundation on which nearly all the calculating
machines have since been constructed to calculate the combinations
of the Arabian numerals represented in Addition, Multiplication,
Subtraction and Division.
In Fig. 2 of the illustration of Pascal’s machine, the machine has been
reversed, and the bottom of the casing, which is hinged, thrown back,
showing the numeral wheels and gearing of the different orders and the
transfer levers for the carry of the tens.
[Sidenote: _Increased capacity of modern calculator_]
The Art of the modern machines is far removed from the older Art by
its greatly increased capacity for rapid calculation which is found
emanating from the provision of keys as the means of manipulation.
To the unsophisticated, such a simple thing as applying keys to the
ancient type of calculating machines that have been made and used for
centuries, would seem but a simple mechanical application that the
ordinary mechanic could accomplish. But it was too great a problem for
the many renowned inventors of the older Art to solve.
Even though the use of depressable keys was common to many machines,
especially the piano, they knew that the organized make-up of their
machines could scarcely stand, without error, the slow action received
from the crank motion or other means employed as manipulating devices.
To place it within the power of an operator to operate their machines
at such a speed as would obtain in the sudden striking of a key would
result in chaos.
[Sidenote: _Patent office a repository of ineffectual efforts_]
There is no room for doubt that some of these early inventors had
the wish or desire to produce such a key-driven machine and may have
attempted to produce one. But as they lacked the advantage of an
institution like the Patent Office in which they could leave a record
of their inoperative inventions, and in view of the fact that they were
dependent on producing an operating machine for credit, there is no
authentic proof that they made attempts in this line.
[Illustration]
[Illustration: Parmelee Patent Drawings]