Chapter II: Part 2

Theoretically, it would seem that the only feature or element lacking in the Art prior to 1886, to produce a real key-driven calculator was means that would control the carrying and also leave the carried wheel free for key actuation. It was, however, quite a different problem. Theoretical functions may be patched together to make a theoretical machine; but that is only theory and not the concrete.

[Sidenote: _All but one of the generic elements solved_]

To take fragmental parts of such machines as were disclosed in the Art and patch them together into anything practical was impossible, even if one had been familiar with the Art and could devise mechanism to supply the new element. That is, leaving aside the broad or generic theoretical elements, which today, from knowledge gained by later inventions, serve the make-up of a key-driven calculator, there was still lacking any concrete example or specific design of a whole machine, as there was no such machine disclosed in the drawings of patents, or any known mechanism which, if arranged in multiples, would be operative as a practical machine even if mechanism to supply the new element were to be added.

In other words, while it is conceded from our present knowledge that all but one of the generic theoretical elements had been solved as disclosed in the various before-named machines, it required the application of these elements in a different way from anything before disclosed; which in itself required a different concrete form of the generic principles for the whole machine as well as a generic form of invention covering the new theoretical element.

It may be easy to analyze that which exists, but quite a different story to conceive that which did not exist. With reference to the Art, however, the production of the new element is a feature that may be credited without question. The concrete does not enter into it other than as proof that a new feature has been created.

[Sidenote: _Originality of inventions_]

While the discussion of the Art from a scientific standpoint brings together in after years what has been accomplished by different inventors, it is doubtful whether any of these early inventors had other knowledge than what may possibly have been obtained from seeing one of the foreign-made crank-driven machines. All inventors work with an idea obtained from some source, but on the whole few copy inventions of others. When an Art is fully established, however, and machines representing the Art are to be found on the market and the principal features of such machines are portrayed in a later patent, it may rightly be called a copy. To assume, however, that a novice has taken the trouble to delve into the archives of the patent office and study the scattered theoretical elements of the Art and supply a new element to make a combination that is needed to produce a practical key-driven calculator, is not a probable assumption. But allowing such assumption were possible, it is evident that from anything that the Art disclosed prior to 1887 it was not possible to solve the concrete production of a key-driven calculator.

[Sidenote: _A conception which led to the final solution_]

In 1884, a young machinist, while running a planer, conceived an idea from watching its ratchet feed motion, which was indirectly responsible for the final solution of the multiple-order key-driven calculating machine. The motion, which was like that to be found on all planing machines, could be adjusted to ratchet one, two, three, four or more teeth for a fine or coarse feed.

While there is nothing in such a motion that would in any way solve the problem of the modern calculator, it was enough to excite the ambitions of the man who did finally solve it. It is stated that the young man, after months of thought, made a wooden model, which he finished early in 1885. This model is extant, and is illustrated on the opposite page.

The inventor was Dorr E. Felt, who is well known in the calculating machine Art as the manufacturer of the “Comptometer,” and in public life as a keen student of economic and scientific subjects. The wooden model, as will be noted, was crude, but it held the nucleus of the machine to come.

Mr. Felt has given some interesting facts regarding his experience in making the wooden model.

[Sidenote: _Evolution of an invention_]

He says: “Watching the planer-feed set me to scheming on ideas for a machine to simplify the hard grind of the bookkeeper in his day’s calculation of accounts.

“I realized that for a machine to hold any value to an accountant, it must have greater capacity than the average expert accountant. Now I knew that many accountants could mentally add four columns of figures at a time, so I decided that I must beat that in designing my machine. Therefore, I worked on the principle of duplicate denominational orders that could be stretched to any capacity within reason. The plan I finally settled on is displayed in what is generally known as the “Macaroni Box” model. This crude model was made under rather adverse circumstances.

“The construction of such a complicated machine from metal, as I had schemed up, was not within my reach from a monetary standpoint, so I decided to put my ideas into wood.

[Sidenote: _Trials of an inventor_]

“It was near Thanksgiving Day of 1884, and I decided to use the holiday in the construction of the wooden model. I went to the grocer’s and selected a box which seemed to me to be about the right size for the casing. It was a macaroni box, so I have always called it the macaroni box model. For keys I procured some meat skewers from the butcher around the corner and some staples from a hardware store for the key guides and an assortment of elastic bands to be used for springs. When Thanksgiving day came I got up early and went to work with a few tools, principally a jack knife.

“I soon discovered that there were some parts which would require better tools than I had at hand for the purpose, and when night came I found that the model I had expected to construct in a day was a long way from being complete or in working order. I finally had some of the parts made out of metal, and finished the model soon after New Year’s day, 1885.”

[Sidenote: _The first “Comptometer”_]

By further experimenting the scheme of the wooden model was improved upon, and Felt produced, in the fall of 1886, a finished practical machine made of metal. This machine is illustrated on the opposite page.

THE FELT CALCULATING MACHINE

Referring to the illustration of Felt’s first metal machine, it will be noted that the machine has been partly dismantled. The model was robbed of some of its parts to be used as samples for the manufacture of a lot of machines that were made later. In view of the fact that this machine is the first operative multiple-order key-driven calculating machine made, it seems a shame that it had to be so dismantled; but the remaining orders are operative and serve well to demonstrate the claims held for it.

[Sidenote: _Felt patent 371,496_]

The mechanism of the machine is illustrated in the reproduction of the drawings of Felt’s patent, 371,496, on page 58. The specification of this patent shows that it was applied for in March, 1887, and issued October 11, 1887.

From the outward appearance of the machine it has the same general scheme of formation as is disclosed in the wooden model.

[Sidenote: _Description of Felt calculator_]

The constructional scheme of the mechanism consists of a series of numeral wheels, marked A in the patent drawings. Each wheel is provided with a ratchet wheel, and co-acting with the ratchet is a pawl mounted on a disc E², carried by the pinion E¹, which is rotatably mounted on the same axis as the numeral wheel. The arrangement of these parts is such that a rotating motion given any of the pinions E¹, in a clockwise direction, as shown in the drawings, would give a like action to their respective numeral wheels; but any motion of the pinions in an anti-clockwise direction would have no effect on the numeral wheels, owing to back-stop pawls K, and stop-pins T, provided to allow movement of the numeral wheels in but one direction.

Co-acting with each pinion E¹, is shown a long lever D, pivoted at the rear of the machine and provided with a segmental gear rack which meshes with the teeth of the pinion E¹. This lever comes under what is now generally termed a segment lever.

Each lever is provided with a spring S, which normally holds the front or rack end upward in the position shown in Fig. 1, and has co-acting with it a series of nine depressable keys which protrude through the casing and contact with the upper edge of the lever.

The arrangement of the keys with their segment levers provides that the depression of any key will depress the segment lever of that order, which in turn will rotate the pinion E¹ and its numeral wheel.

While this arrangement is such that each key of a series gives a different degree of leverage action to the segment lever, and in turn a degree of rotation to the numeral wheel of the same order in accordance with the numerical value of the key depressed, it may be conceived that the momentum set up by the quick stroke of a key would set the numeral wheel spinning perhaps two or three revolutions, or at any rate way beyond the point it should stop at to register correctly.

To preserve correct actuation of the mechanism and overcome its momentum, Felt provided a detent toothed lever for each numeral wheel, which will be found marked J¹ in the drawings. To this lever he linked another lever G, which extended below the keys, and arranged the length of the key-stems so that when each key had revolved the numeral wheel the proper distance, the key will have engaged the lever G, and through the link connection will have caused the detent tooth of the lever J¹ to engage one of the pins T, of the numeral wheel, thus bringing the numeral wheel and the whole train of mechanism to a dead stop.

This combination was timed so that the (1) key would add one, the (2) key would add two, etc., up to nine for the (9) key. Thus the prime actuation of each wheel was made safe and positive.

[Sidenote: _Recapitulation of Art prior to Felt calculator_]

Before explaining the means by which the carry of the tens was effected in the Felt machine without interfering with multiple-order prime actuation, it will perhaps help the reader to recapitulate on what the Art already offered.

Going back to the Art, prior to Felt’s invention, there are a few facts worth reconsidering that point to the broadly new contributions presented in the Felt invention, and combining these facts with a little theory may perhaps give a clearer understanding of what was put into practice.

In most lines of mechanical engineering in the past, the term “theory” connected with mechanical construction was a bugaboo. But the solution of the modern calculating machine was wholly dependent upon it.

Let us summarize on the Art, prior to Felt’s invention. A calculating machine that would calculate, if we eliminate the key-driven feature, was old. The key-driven feature applied to adding mechanism was old as adapted to a single-order machine with a capacity for adding only a single column of digits.

[Sidenote: _Why Hill failed to produce an operative machine_]

Hill attempted to make a multiple order key-driven machine, but failed because he did not theorize on the necessities involved in the physical laws of mechanics.

Hill saw only the columnar arrangement of the ordinal division of the keyboard, and his thought did not pass beyond such relation of the keys for conveyance. There is no desire to belittle this feature, but it did not solve the problem that was set forth in the specification and claims of his patent; neither did it solve it for anyone else who wished to undertake the making of such a machine.

[Sidenote: _Idiosyncrasies of force and motion increased by use of keys_]

The introduction of keys as a driving feature in the calculating machine Art demanded design and construction suitable to control the new idiosyncrasies of force and motion injected into the Art by their use, of which the elements of inertia and momentum were the most troublesome.

[Sidenote: _Light construction a feature_]

Hill, in the design and construction of his machine, ignored these two elementary features of mechanics and paid the penalty by defeat. The tremendous speed transmitted to the parts of a key-driven machine, which has already been illustrated, required that lightness in construction which is absolutely necessary to reduce inertia to a minimum, should be observed. The Hill machine design is absolutely lacking in such thought. The diameter of the numeral wheel and its heavy construction alone show this. Lightness of construction also enters into the control of momentum when the mechanism must suddenly be brought to a dead stop in its lightning-speed action. A heavily-constructed numeral wheel like that shown in the Hill patent would be as hard to check as it would to start, even if Hill had provided means for checking it.

Strength of design and construction, without the usual increase in weight to attain such end, but above all, the absolute control of momentum, were features that had to be worked out.

Robjohn partly recognized these features, but he limited the application of such reasoning to the prime actuation of a single order, and made nothing operable in a multiple key-driven machine.

Spalding and Bouchet recognized that the application of control was necessary for both prime actuation and carrying, but, like Robjohn, they devised nothing that would operate with a series of keys beyond a single order.

[Sidenote: _Operative features necessary_]

An operative principle for control under prime actuation was perhaps present in some of the single-order key-driven machines, but whatever existed was applied to machines with keys arranged in the bank form of construction, and, to be used with the keys in columnar formation, required at least a new constructive type of invention. But none of the means of control for carrying, prior to Felt’s invention, held any feature that would solve the problem in a multiple-order machine.

[Sidenote: _Classification of the features contained in the early Art of key-driven machines_]

While all the machines referred to have not been illustrated and described here, fair samples of the type that have any pertinence to the Art have been discussed, and those not illustrated would add nothing more than has been shown. A classification of the inventions referred to may be made as follows:

Parmelee and Stetner had no carrying mechanism; Hill, Robjohn, Borland and Hoffman, Swem, Lindholm and Smith had no control for the carry. Carroll, Bouchet and Spalding show a control for the carrying action, which in itself would defeat the use of a higher wheel for prime actuation, and which obviously would also defeat its use in a multiple-order key-driven machine.

One of the principal reasons why theory was necessary to solve the problem of the key-driven calculator existed in the impossibility of seeing what took place in the action of the mechanism under the lightning speed which it receives in operation. Almost any old device could be made to operate if moved slow enough to see and study its action; but the same mechanism that would operate under slow action would not operate correctly under the lightning-speed action they could receive from key depression. Only theoretical reasoning could be used to analyze the cause when key-driven mechanism failed to operate correctly.

[Sidenote: _Carrying mechanism of Felt’s calculator_]

Referring again to the drawings of the Felt patent, which illustrate the first embodiment of a multiple-order key-driven calculating machine, we find, what Felt calls in the claims and specifications, a carrying mechanism for a multiple-order key-driven calculating machine. This mechanism was, as set forth in the specification, a mechanism for transferring the tens, which have been accumulated by one order, to a higher order, by adding one to the wheel of higher order for each accumulation of ten by the lower order wheel. This, in the Felt machine, as in most machines, was effected by the rotation of a numbered drum, called the numeral wheel, marked with the nine digits and cipher.

[Sidenote: _Transfer devices_]

The term “transfer device” for such mechanism was in common use, and as a term it fits certain parts of all classes of devices used for that purpose, whether for a crank-driven, key-driven, or any other type of multiple-order or single-order machine. But in the Felt invention we find it was not the simple device generally used for transferring the tens. It was, in fact, a combination of devices co-acting with each other which, in the specification of the patent, was termed the carrying mechanism.

[Sidenote: _Carrying mechanism versus mere transfer devices_]

Now, carrying mechanism may in a sense be termed a transfer device, as one of its functions is that of transferring power to carry the tens, but a mere transfer device may not be truthfully termed a carrying mechanism for a multiple-order key-driven machine unless it performs the functions that go to make up a correct carrying of the tens in that class of machine, and which we find laid down under the head of carrying mechanism in the Felt patents, where we find the first operative carrying mechanism ever invented for a multiple-order key-driven machine.

The functions demanded of such a piece of mechanism are as follows: First, the storing of power to perform the carry; second, the unlocking of the numeral wheel to be carried; third, the delivery of the power stored to perform such carry; fourth, the stopping and locking of the carried wheel when it has been moved to register such carry; and fifth, clearing the carrying-lock during prime actuation. A seemingly simple operation, but let those who have tried to construct such mechanism judge; they at least have some idea of it and they will no doubt bow their heads in acknowledgment of the difficulties involved in this accomplishment.

Mechanism for carrying the tens in single digit adders was one thing, and such as was used could well be called a transfer device; but mechanism for carrying the tens in a real key-driven calculating machine was another thing, and a feature not solved until Felt solved it, and justly called such combination of devices a “carrying mechanism.”

[Sidenote: _Details of Felt carrying mechanism_]

In the Felt machine, the carrying mechanism consisted of a lever and ratchet pawl action, constructed of the parts M, m², operated by a spring m, the pawl acting upon the numeral wheel pins T, to ratchet the wheel forward under the spring power. The power in the spring was developed from the rotation of the lower wheel, which through the means of an envolute cam[2] attached to left side of each wheel, operated the carrying lever in the opposite direction to that in which it was operated by the spring. As the carrying lever passed the highest point of the cam spiral and dropped off, the stored power in the spring retracted the lever M, and the pawl m², acting on the higher order wheel pins T, and moved it one-tenth of a revolution.

[2] NOTE: As all the drawings of the Felt patent are not reproduced here, the cam is not shown.

This part of the mechanism was in principle an old and commonly-used device for a one-step ratchet motion used in the carry of the tens. It served as a means of storing and transferring power from the lower wheel to actuate the higher wheel in a carrying operation, but a wholly unqualified action without control.

In the Felt machine a spring-actuated lever N, mounted on the same axis with the carrying lever, and provided with a detent stop-hook at its upper end, served to engage the numeral wheel at the end of its carried action, and normally hold it locked.

An arm or pin P, fixed in and extending from the left side of the carrying lever and through a hole in the detent lever, acted to withdraw the detent lever from its locking engagement with the numeral wheel as the carrying lever reached the extreme point of retraction; thus the wheel to be carried was unlocked.

Pivoted to the side of the detent lever is a catch O. This catch or latch is so arranged as to hook on to a cross-rod q, especially constructed to co-act with the catch and hold the detent lever against immediate relocking of the numeral wheel as the carrying lever and pawl act in a carrying motion. The latch has a tail or arm p, which co-acts with the pin P on the carrying lever in such a way as to release the latch as the carrying lever finishes its carrying function.

Thus the detent lever N is again free to engage one of the control or stop-pins T to stop and lock the carried numeral wheel when the carrying lever and pawl, through the action of the spring stored in the carrying, has moved the wheel the proper distance.

A lot of functions to take place in ¹/₁₆₅ of a second, but it worked. The timing of the stop and locking detents, of course, was one of the finest features.

The normal engagement of the carrying detent, it may be understood, would prevent the movement of the wheel by key action or prime actuation, but the patent shows how Felt overcame this.

The carrying stop and locking detent lever N is provided with a cam-arm or pin N, which was arranged to co-act with the cam disc E (see Fig. 1), fast to the prime actuating pinion E. The cam surface was short and performed its function during a short lost motion arranged to take place before the ratchet pawl would pick up and move the numeral wheel under key actuation.

The camming action was outward and away from the center, and thus released the carrying stop from its locking position with the numeral wheel, and continued rotation of the pinion and cam disc would hold the lock out of action until the parts had returned to normal.

With the return action of the keys, segment lever, pinion and cam disc, through the action of a spring attached to the segment lever, the carrying stop detent will again engage and lock the numeral wheel.

[Sidenote: _Manufacture of the Felt calculator_]

Felt really started to manufacture his calculating machine in the fall of 1886, after perfecting his invention. Having only a very limited amount of money with which to produce machines, young Felt, then but 24 years of age, was obliged to make the machines himself, but with the aid of some dies which he had made for some of the principal parts (see reproduction of bill for dies on opposite page), he was able to produce eight finished machines before September, 1887. Two of these machines were immediately put into service, for the training of operators, as soon as they were finished.

[Sidenote: _Trade name of Felt calculator_]

Of the first trained operators to operate these machines, which were given the trademark name “Comptometer,” one was Geo. D. Mackay, and another was Geo. W. Martin. After three or four months’ practice Mr. Martin demonstrated one of these machines to such firms as Sprague, Warner & Co., Pitkin & Brooks, The Chicago Daily News, and the Chicago, Burlington & Quincy R. R. Co., and finally took employment with the Equitable Gas Light & Fuel Co. of Chicago (see letter on opposite page) as operator of the “Comptometer.” The Gas Co. has since been merged with several other companies into the Peoples Gas Light & Coke Co. of Chicago.

A very high testimonial of the qualities of the Felt invention was given by Mr. Martin in 1888, a year after he entered the employment of the Gas Co., and is reproduced on page 72.

Another fine testimonial was given by Geo. A. Yulle, Secy. & Treas. of the Chicago Gas Light & Coke Co., in September, 1888 (see page 74). Mr. Mackay, the other operator, secured employment with Albert Dickinson & Co., Seed Merchants, as operator of the “Comptometer.” Mr. Mackay was interviewed a few months ago, and was at that time, after thirty years, still with the same firm, and a strong advocate of the “Comptometer.”

[Sidenote: _Felt calculator Exhibit at National Museum_]

In September, 1887, Felt took one of the first eight machines to Washington and exhibited it to Gen. W. S. Rosecrans, then Registrar of the Treasury, and left the machine in the office of Dr. E. B. Elliott, Actuary of the Treasury, where it was put into constant use. Proof of the date of this use of Felt’s invention in the Treasury is set forth in the reproduction of two letters (see opposite page), one was written by Mr. Elliott and another by Gen. W. S. Rosecrans, in answer to an inquiry of the Hall Typewriter Co. of Salem, Mass. Another of the first eight machines was placed with Dr. Daniel Draper, of the N. Y. State Weather Bureau, New York City.

Felt finally closed a deal with Mr. Robert Tarrant of Chicago, whereby a partnership contract was signed November 28, 1887. The partnership was incorporated January 25, 1889, under the name of the Felt & Tarrant Mfg. Co., who are still manufacturing and selling “Comptometers” under that name.

[Sidenote: _Significant proof of Felt’s claim of priority_]

Laying aside all the evidence set forth in the foregoing history of key-driven machines and their idiosyncrasies, significant proof of Felt’s claim as the first inventor of the modern calculating machine is justified by the fact that no other multiple-order key-driven calculating machine was placed on the market prior to 1902.

Lest we lose sight of a most important feature in dealing with the Art of the Modern Calculator, we should call to mind the fact that as Felt was the originator of this type of machine, he was also the originator of the scheme of operation in its performance of the many and varied short cuts in arithmetical calculation.

The performance of calculation on machines of the older Art differed so entirely from the new that any scheme of operation that may have been devised for their use would lend nothing to the derivation of the new process for operating the key-driven machine of the new Art.

[Sidenote: _Rules for operation an important factor of modern calculator_]

A superficial examination of one of the instruction books of the “Comptometer” will convince most any one that it is not only the mechanism of the machine that made the modern calculator so valuable to the business world, but also the schemes laid down for its use. The instructions for figuring Multiplication, Subtraction, Division, Square Root, Cube Root, Interest, Exchange, Discount, English Currency, etc., involved hard study to devise such simple methods and rules.

The instruction books written by Felt for the “Comptometer, the Modern Calculator,” reflect the genius disclosed in the invention of the machine itself.

Early Efforts in the Recording Machine Art

The Art of recording the addition of columns of figures is old in principle, but not in practice. Many attempts to make a machine that would record legibly under all conditions failed. These attempts have been pointed out from time to time as the first invention of the recording-adding machine, especially by those desirous of claiming the laurels.

[Sidenote: _First attempt to record arithmetical computation_]

The first attempt at arithmetical recording for which a patent was issued, was made by E. D. Barbour in 1872 (see illustration on opposite page).

E. D. Barbour has also the honor of being the first inventor to apply Napier’s principle to mechanism intended to automatically register the result of multiplying a number having several ordinal places by a single digit without mentally adding together the overlapping figures resulting from direct multiplication. He patented this machine in 1872 just prior to the issue of his arithmetical recorder patent. (See page 181.)

THE BARBOUR MACHINE

The printing device disclosed in connection with the Barbour machine for recording calculations was of the most simple nature, allowing only for the printing of totals and sub-totals.

Its manipulation consisted of placing a piece of paper under a hinged platen and depressing the platen by hand in the same manner that a time stamp is used. The ink had to be daubed on the type by a hand operation to make legible the impressions of the type.

[Sidenote: _Description of Barbour machine_]

The patent drawings of the Barbour machine are so fragmentary that it is almost impossible to draw any conclusion as to its functions without reading the specifications.

Fig. 1 represents the base of the machine, while Fig. 4 shows a carriage which, when in place, is superimposed above the base as illustrated in Figs. 3 and 5.

The operation of the machine is performed by first pulling out the slides B (shown in Fig. 1), which set the digital degrees of actuation of each order; and, second, by operating the hand-lever K, from its normal position at 0 to 1, if it is desired to add, or to any of the other numbers in accordance to the value of the multiplier if multiplication is desired.

The movement of the handle K, from one figure to the other, gives a reciprocation to the carriage, so that for each figure a reciprocation will take place.

Each of the slides B, has a series of nine gear racks; each rack has a number of teeth ranging progressively from 1 tooth for the first gear rack to 9 teeth for the last rack, thus the pulling out of the slides B will present one of the gear racks in line to act upon the accumulator mechanism of the carriage as the carriage is moved back and forth over it.

The accumulator mechanism consists of the register wheels M¹ and M² and the type wheels M³ and M⁴ mounted on a common arbor and a carry transfer device between the wheels of each order.

Operating between the accumulator wheels and the racks of plate B are a pair of gears, one in the form of a lantern wheel loosely mounted on the accumulator wheel shaft but connected thereto by a ratchet wheel and pawl connection; the other, a small pinion meshing with the lantern wheel on a separate axis, protrudes below the carriage into the path of the racks.

Thus as the carriage is moved by the reciprocating device connected with the hand-lever K, the pinions of the accumulator will engage whatever racks have been set and the numeral wheels and type wheels will be operated to give the result.

The numeral and type wheels have two sets of figures, one of which is used for addition and multiplication, while the other set runs in the opposite direction for negative computation or subtraction and division.

A plate arranged with sight apertures covers the numeral or register wheels, while the type wheels are left uncovered to allow a hinged platen F, mounted on the top of the carriage (see Fig. 3), to be swung over on top of them and depressed.

Attached to the platen F, are a series of spring clips d, under which strips of paper may be slipped (as shown by D, in Fig. 4), and which serves to hold the paper while an impression is taken.

[Sidenote: _Barbour machine not practical_]

Thus the Barbour invention stands in the Art as something to show that as early as 1872 an effort was made to provide means to preserve a record of calculations by printing the totals of such calculations.

THE BALDWIN MACHINE

The next effort in this class of machines is illustrated in a patent issued to Frank S. Baldwin in 1875 (see illustration on opposite page). The Baldwin machine is also of moment as having the scheme found in the machines known as the Brunsviga, made under the Odhner patents--a foreign invention, later than that of Baldwin, used extensively abroad and to a limited extent in this country.

The contribution of Baldwin to the Art of recording-calculating devices seems to be only the roll-paper in ribbon form and the application of the ink ribbon. The method used by Barbour for type impression was adapted and used by Baldwin; that is, the hinged platen and its operation by hand.

Of the illustrations shown of the Baldwin machine, one is reproduced from the drawings of the patent while the other is a photo reproduction of the actual machine which was placed on the market, but, as may be noted, minus the printing or recording device shown in the patent drawings.

[Sidenote: _Description of Baldwin machine_]

Referring to the photo reproduction, the upper row of figures showing through the sight apertures in the casing are those of the numeral wheels which accumulate the totals, and which in the patent drawings would represent the type of the accumulator wheels for printing the totals of addition and multiplication or the remainders of subtraction and division.

The figures showing below serve to register multiples of addition and subtraction which would read as the multiplier in multiplications or the quotient in division. These wheels are the type wheels N, in the patent drawings, which serve the purpose of recording the named functions of calculation.

The means by which the type wheels of the upper row are turned through the varying degrees of rotation they receive to register the results of calculation, consists of a crank-driven, revolvable drum, marked E, which is provided with several denominational series of projectable gear teeth h, which may be made to protrude through the drum by operation of the digital setting-knobs g, situated on the outside of the drum.

These knobs, as shown in the patent drawings, are fast to radial arms, each of which serves as one of three spokes of a half-wheel device, operating inside the drum and pivoted on the inner hub of the drum.

These half wheels marked F, in the drawings, by means of their cam faces h¹, serve to force the gear teeth out through the face of the drum, or let them recede under the action of their springs as the knobs g, are operated forward and back in the slots x, of the drum provided for the purpose.

As will be noted from the photographic reproduction of the machine, these slots are notched to allow the arms extending through them to be locked in nine different radial positions, and that each of these positions are marked progressively from 0 to 9.

This arrangement allows the operator to set up numbers in the different orders by springing the setting-knobs g to the left and pulling them forward to the number desired, where it will become locked in the notch when released. This action will have forced out as many gear teeth in each order as have been set up by the knobs g in their respective orders.

The lateral positions of the projectable gear teeth correspond to the spacing of the type-wheels, and an intermediate gear G, meshing with each type, or register wheel, is loosely mounted on the shaft H, interposed between the said wheels and the actuating drum E, so that when the drum is revolved by the crank provided for that purpose, the gear teeth protruding from the drum will engage the intermediate gears G, and turn them and their type or register wheels as many of their ten points of rotation as have been set up in their respective orders of the setting devices of the drum.

Revolving the drum in one direction adds, while revolving it in the opposite direction subtracts, and repeated revolutions in either direction give respectively the multiple forms of addition or subtraction which result in either multiplication or division, as the case may be.

The actuating drum E, is provided with means by which it may be shifted to the left to furnish means for multiplying by more than one factor and to simplify the process of division.

The means for the carry of the tens consist of a series of teeth i, formed by the bent end of a pivoted spring-pressed lever arm which is pivoted to the inside of the actuating drum with the tooth protruding through a slot in the drum, so arranged as to allow motion of the tooth in a direction parallel to the drum axis.

Normally these teeth are held in a position to escape engagement with the intermediate gears G, but provision is made for camming the teeth i, to the left into the path of an intermediate gear of one order as the type or register wheel of the lower order passes from 9 to 0.

The parts which perform this function are the cam m, located on the left side of each wheel, the plunger M, which operates in the fixed shaft H, and which has a T-shaped head that, when projected into the path of the carrying teeth i, serve to cam them sidewise and bring about the engagement referred to, which results in the higher type or numeral wheel being stepped forward one space.

The cam-lugs j on the drum serve to engage and push back the T heads of the cam plungers M, after they have brought about the one-step movement of the higher wheel.

[Sidenote: _Baldwin’s printing mechanism_]

The printing device consists of a hand-manipulated frame pivoted to the main frame of the machine by the shaft t. The paper is supplied from a roll about the shaft t, and an ink-ribbon is fed back and forth from the rolls u and u¹ over bars of the printing-frame which protrude through slots in the casing and act as platens for the impression of the paper and ink-ribbon against the type.

It is presumed that the paper was torn off after a record was printed in the same manner as in the more modern machines.

THE POTTIN MACHINE

Eight years after the Baldwin patent was issued, a Frenchman named Henry Pottin, residing in Paris, France, invented a machine for recording cash transactions, which he patented in England in 1883 and in the United States in 1885 (see illustration on opposite page).

The form and design of the machine, as will be noted, correspond quite favorably with the scheme of the present-day cash register, although it lacks the later refinement that has made the cash register acceptable from a visible point of view.

[Sidenote: _First key-set crank-operated machine and first attempt to record the items in addition_]

The Pottin invention is named here as the first in which two of the prime principles of the recording-adders of today are disclosed; one is the depressable key-set feature and the other is the recording of the numerical items. The Pottin machine was the first known depressable key-set crank-operated machine made to add columns of figures and the first machine in which an attempt was made to print the numerical items as they were added.

Turning to the illustration of the U. S. patent drawings of the Pottin machine, the reader will note that there are four large wheels shown, marked B. These wheels are what may be called the type-wheels, although they also serve as indicator wheels for registering cash sales. The type figures are formed by a series of needles fixed in the face of the wheels.

The means employed for presenting the proper type figure for printing and likewise the indicator figures to indicate the amount set up in each denominational order was as follows:

Referring to Fig. 1, it will be noted that to each type-wheel is geared a spring-actuated segmental rack marked D, which, as shown in the drawing, is in contact with a pin marked i, which protrudes from the side of the depressed number (9) key.

The normal position of the rack D, is indicated in dotted lines showing the next higher sector which has not been displaced by key depression.

[Sidenote: _Description of Pottin machine_]

Each key, as will be noted from Fig. 7, is provided with one of the pins i, which is normally out of the path of the lug j, as the racks D, drop forward; but when any key is depressed the pin is presented in the path of the lug j, and stops further forward action of the rack.

It will be noted that the arrangement of the keys is such as will allow progressively varying degrees of action to the segmental racks D. This variation, combined with the geared relation of the type-wheels and racks is equivalent to a tenth of a rotation of the type-wheel for each successive key in the order of their arrangement from 1 to 9.

The means provided for holding the segmental racks D, at normal, also serves to hold a key of the same order depressed, and consists of a pivoted spring-pressed latch-frame marked E (see Figs. 7 and 8).

With such a combination, the depression of keys in the several orders will unlatch the segmental racks, and the racks, through the tension of their actuating springs, will turn the wheels and present a type corresponding to the numerical value of each key depressed.

A hand lever, marked R, located on left side of the machine provides power for printing the items. Another hand lever, marked J, serves to restore the segmental racks, type-wheels and the keys to normal, and through the co-operation of the lever R, adds the items to the totalizer numeral wheels, which are shown in Fig. 1 as the numbered wheels marked v.

The paper is supplied from a roll mounted on a hinged platen frame P¹, supported in its normal position by a spring P³. The paper passes under the roller P, which acts as a platen for the impression of the type. A shaft Q, passing under the frame P¹, is fast and rigidly connected on the left-hand side of the machine with the hand lever R, and acts as a pivot for the said lever and by means of lateral projections q, serves when the lever R is operated to engage the frame P¹, and depresses it until the needle types have pricked the numerical items through the paper.

A slit in the casing provided means for printing the item on a separate piece of paper or bill.

Although there is no means shown by which the paper is fed after an item is printed, it is claimed in the specification that the well-known means for such feeding may be employed. The actuating lever J referred to, is connected by a ratchet and geared action with the shaft F[3], so that a revolution is given the said shaft each time the lever is operated.

[3] NOTE: All the drawings of the Pottin patent are not shown here.

To the shaft F, (see Fig. 1) is attached a series of arms H, one for each order, which, as the shaft revolves in the direction of the arrow, engages a lug marked I, on the segmental racks D, thus rocking the segments back to normal, turning the type-wheels with them.

The return of the segment racks D, cause the back of the latch-tooth f¹, (see Fig. 8) to engage the latch-tooth f, of the latch bar E, camming it out of engagement with the keys so that any key that has been set will return by means of its own spring.

The total or accumulator numeral wheels are connectable with the type or indicating wheels B, by an engaging and disengaging gear motion set up by the combined action of the hand levers R and J, which first cause such gear engagement, and then, through the return of the type wheels to zero, turn the accumulator wheels, thus transferring the amount of the item set upon the type wheels to the accumulator wheels.

The specification claims the machine is intended for use by cashiers, bank-tellers, and others, to record receipts or disbursements.

It is also claimed in the specification that instead of the needle type ordinary type may be used in combination with an inking ribbon if so desired.

[Sidenote: _Early efforts of Wm. S. Burroughs_]

One of the next attempts to produce a recording-adder was made by Wm. S. Burroughs, whose name sixteen years later was used to rename the American Arithmometer Co., now known as the Burroughs Adding Machine Co.

The first patent issued to Burroughs, No. 388116, under date of August 21, 1888, like the machine of Barbour and Baldwin, was designed to record only the final result of calculation.

On the same date, but of later application, another patent, No. 388118, was issued to Burroughs which claimed to combine the recording of the numerical items and the recording of the totals in one machine. Some of the drawings of this patent have been reproduced. (See opposite page.)

MACHINE OF EARLY BURROUGHS PATENT

Referring to the drawings of the Burroughs patent, it will be noted, that in outward form, the machine is similar to the Burroughs machine of today. To give a detailed description of the construction of the machine of this Burroughs patent would make tedious reading and take unnecessary space.

[Sidenote: _General scheme of Burroughs’ first inventions_]

The principle involved in the mechanism for recording the items is very similar to that of the Pottin invention; the setting of the type wheels being effected as in the Pottin machine by means of segment gears which the depression of the keys serves to unlatch, and acts to gauge the additive degree of their movement.

Burroughs used the inking form of type proposed as an alternative by Pottin in his patent specification instead of the needles shown in the Pottin drawings.

In the Burroughs patent, as in the Pottin, it will be noted that there are two sets of wheels bearing figures, one set of which, marked J, situated at the rear, are the type-wheels, and the other set, marked A, at the front of the machine, are for the accumulation of the totals.

For each denominational order of the type and total wheels, there is provided an actuating segmental gear, consisting of a two-armed segmental lever pivoted to the shaft C, and having the gear teeth of its rear arm constantly in mesh with the pinion gear of the type-wheel J, and the gear teeth of the forward arm normally presented to, but out of mesh with the pinion gear of its total wheel A.

Each of these denominational actuators or segment gears is provided with a stop projection X², at the top end of its forward gear rack, which serves as a means for interrupting the downward movement of that end of the segment lever, and thus controls its movement as a denominational actuator.

It will be noted that instead of the key-stems acting directly as a stop for the denominational actuators, as in the Pottin invention, Burroughs used a bell crank type of key lever and the stop-wire C¹ as an intermediate means, and in this manner produced a flat keyboard more practical for key manipulation.

[Sidenote: _Brief description of machine of early Burroughs patents_]

The stop-wires C¹, as will be noted, are arranged to slide in slots of the framework, and while normally not presented in the path of the stop-projection X², of the denominational actuators, it may be observed that by the depression of the proper key any one of them may be drawn rearward and into the path of the stop projection X², of its related actuator, and thus serve as a means to intercept the downward action of the actuator.

The denominational actuators in the Burroughs machine were not provided with spring tension that would cause them to act as soon as unlatched by depression of the keys as has been described in relation to the Pottin invention.

While the keys in the Burroughs machine, as in the Pottin invention, served also to unlatch the denominational actuators in their respective orders, no movement of the said actuators or type-wheels took place until a secondary action was performed.

The secondary action, or the operation of the hand lever, marked C⁵, attached to the shaft C, on its initial or forward stroke dragged the denominational actuators down by means of friction and thus set the type-wheels, and by means claimed in the specification, brought about the type impression to print the result of the key-setting or the item so set.

The backward or rear stroke of the hand lever caused the accumulator or total numeral wheels to be engaged and the item to be added to them.

From this single lever action it will be noted that there is an improvement shown over and above the Pottin invention in the fact that but one lever motion is required; Pottin having provided two levers so that in the event of error the operation of one lever would reset the machine without performing any addition or printing.

In the Burroughs invention, the motion of denominational actuators and their type-wheels not being effected through depression of keys, as in the Pottin machine, allowed any error in the setting up of an item to be corrected by the resetting of the keys and relatching of the gears, which it is claimed was provided for by operation of the lever marked B⁷ (Fig. 1 of the drawings).

As a means of supplying power to his denominational actuators, Burroughs provided what may be called a universal actuator common to all orders, composed of a rock-frame (arms D², loose on each end of actuating shaft C, and having their outward ends rigidly connected by the bar a⁹) and the arms E, fixed to each end of the shaft C.

Projecting from the inside of each of the arms E, are two lugs, b¹ and b³, which contact with the arms D² of the rock-frame as the shaft C is rocked back and forth by its hand crank C⁵, and thus lower and raise the rock-frame.

The means employed to transmit the reciprocating action of the universal actuator to such denominational actuators as may be unlatched by key depression, consists of a series of spring-pressed arc-shaped levers D¹, pivoted to the rock-frame bar a⁹, which bear against a pin b² fixed in the front arm of the denominational actuators.

Each of the levers D¹, is provided with a notch y, which serves on the downward action of the rock-frame to engage the pins b², of the denominational actuators and draw down with them such actuators as have been unlatched by key depression and to pass over the pins of such actuators as have not been unlatched.

When in the course of such downward movement the denominational actuators are intercepted by the stop-wires C¹, the yielding spring pressure of the levers D¹, allow the notches y, to slip over the pins b², and leave the denominational actuators and their type-wheels set for recording the item thus set up.

The means provided for impression of the type is shown in other drawings of a patent not reproduced here. The means provided consisted of a universal platen, which, the specification states, serves to press the ink-ribbon and paper against the type after all the figures of each item were set.

While Barbour, Baldwin and Pottin all used the universal platen to print the collective setting of type represented in the items or totals, as the case may be, each varied somewhat in detail. Baldwin used a toggle to press the platen toward the type, while Burroughs used a spring to press the platen against the type and a toggle to press it away from the type.

Burroughs claimed to have combined in his invention the printing of the totals, with the printing of the items, each of which it has been shown was claimed by the patentees of previous inventions but had not been combined in one machine prior to the Burroughs attempt.

The process for recording these totals in the Burroughs patent consisted of utilizing the action of the total wheels during their resetting or zeroizing movement to gauge the setting of the type-wheels.

The specification shows that, during the downward motion or setting of the denominational actuators, as they set the type wheels, the numeral wheels are out of gear and receive no motion therefrom; and that after the recording of each item and during the return motion of denominational actuators, the numeral or total wheels are revolved forward in their accumulative action of adding the items and thus registering the total.