Origin of modern calculating machines

by J. A. V. Turck

Bouchet Machine

The [illustration of the Bouchet machine] on the opposite page was reproduced from the drawings of the patent which is the nearest to the machine that was placed on the market. The numeral wheels, like most of the single-digit adders, are three in number, and consist of the prime actuated, or units wheel, and two overflow wheels to receive the carry of the tens. The units wheel has fixed to it a long 10-tooth pinion or rotor I, with which nine internal segmental gear racks L, are arranged to engage and turn the units wheel through their nine varying additive degrees of rotation.

Description of Bouchet machine

The segmental gear racks L, are normally out of mesh with the pinion I, and are fast to the key levers E, in such a manner that the first depression of a key causes its rack to rock forward and engage with the pinion I, and further depression moves the rack upward and rotates the pinion and units numeral wheel. It will be noted that this engaging and disengaging gear action is in principle like that of Robjohn.

The transfer devices for the carry of the tens, as already stated, belong to that class of mechanism commonly known as the “Geneva motion.” It consists of a mutilated or one-tooth gear fast to the units wheel operating with a nine-tooth gear, marked D¹, loosely mounted on an axis parallel to the numeral wheel axis. Each revolution of the units wheel moves the nine-tooth gear three spaces, and in turn moves the next higher numeral wheel to which it is geared far enough to register one point or the carry. A circular notched disc, marked S, is fast to the units wheel, and the nine-tooth gear D¹, has part of two out of every three of its teeth mutilated or cut away to make a convex surface for the notched disc to rotate in.

With such construction the nine-tooth gear may not rotate or become displaced as long as the periphery of the disc continues to occupy any one of the three convex spaces of the nine-tooth gear. When, however, the notch of the disc is presented to the mutilated portion of the nine-tooth gear, the said gear is unlocked. This unlocking is coincident to the engagement of the single tooth of the numeral wheel-gear with the nine-tooth gear and the passing of the numeral wheel from 9 to 0, during which the nine-tooth gear will be moved three spaces, and will be again locked as the notch in the disc passes and the periphery fills the next convex space of the mutilated nine-tooth gear.

Bouchet machine marketed

The Bouchet machine was manufactured and sold to some extent, but never became popular, as it lacked capacity. Machines of such limited capacity could not compete with ordinary accountants, much less with those who could mentally add from two to four columns at a clip. Aside from the capacity feature, there was another reason why these single-order machines were useless, except to those who could not add mentally. Multiple forms of calculation, that is, multiplication and division, call for a machine having a multiplicity of orders. The capacity of a single order would be but 9 × 9, which requires no machine at all—a seven-year-old child knows that. To multiply 58964 × 6824, however, is a different thing, and requires a multiple-order calculator.

Misuse of the term “Calculating Machine”

It is perhaps well at this time to point out the misuse of the term calculating where it is applied to machines having only a capacity for certain forms of calculating as compared with machines which perform in a practical way all forms of calculation, that is, addition, multiplication, subtraction and division. To apply the term “calculating machine” to a machine having anything less than a capacity for all these forms is erroneous.

An adding machine may perform one of the forms of calculation, but to call it a calculating machine when it has no capacity for division, subtraction or multiplication, is an error; and yet we find the U. S. Patent Office records stuffed full of patents granted on machines thus erroneously named. The term calculating is the broad term covering all forms of calculation, and machines performing less should be designated according to their specific capacities.

It is true that adding is calculating, and under these circumstances, why then may not an adding machine be called a calculator? The answer is that it may be calculating to add; it may be calculating to either subtract, multiply or divide; but if a machine adds and is lacking in the means of performing the other forms of calculation, it is only part of a calculating machine and lacks the features that will give it title to being a full-fledged calculator.[1]

Considerable contention was raised by parties in a late patent suit as to what constituted the make-up of a calculating machine. One of the attorneys contended that construction was the only thing that would distinguish a calculating machine. But as machines are named by their functioning, the contention does not hold water. That is to say: A machine may be a calculating machine and yet its construction be such that it performs its functions of negative and positive calculation without reversal of its action.

Again, a machine may be a calculating machine and operate in one direction for positive calculation and the reverse for negative calculation. As long as the machine has been so arranged that all forms of calculation may be performed by it without mental computation, and the machine has a reasonable capacity of at least eight orders, it should be entitled to be called a calculating machine.

Drawings of Spalding Patent No. 293,809