shoulder the spring operates on the pawl and rotates the higher order wheel one step, so that the figure 1 will show on the higher wheel and the cipher or some figure between that and 9 on the lower. Thus the carry is made, no matter what keys of the lower order wheel may be operated.

To illustrate this carrying operation suppose the 9 key in the units. column is struck 12 times so that the sum will be 108. On the first stroke the units wheel turns nine-tenths of a revolution, and the tens wheel does not move because its pawl M' has not yet been actuated by the units wheel cam and the tens wheel pawl spring. But when the 9 is struck again the units wheel revolves another nine-tenths, and turns up an 8, and the carry has been made so as to move the tens wheel one step, and show 18 on the top of the two wheels. When the third stroke is made the units wheel will show 7 and another carry occurring the tens wheel will show 2. So with each successive stroke the units wheel goes nearly around, and the tens wheel advances one step until the eleventh, where it remains stationary because the units wheel was then starting as at the beginning with the cipher uppermost; but when the twelfth stroke is made the units wheel cam and the tens pawl move the tens wheel one step, and the tens wheel (having now completed one revolution) has by its cam and the hundreds wheel pawl operated on the hundreds wheel to move it one step, so that the final result of all the strokes on the 9 key is 1 on the hundreds wheel, a cipher on the tens and an 8 on the units, or 108.

A novel improvement on this carrying device, covered by claim 29 of the first patent in suit, No. 762,520, presents the chief question in the case, and will be explained after adverting to the third point, the stop mechanism.

The Stop Mechanism. The third requisite of an adding or calculating machine is to provide automatic catches or stops to prevent overrun of a wheel. Without such stops the rapid striking of a key might rotate the wheel so far as to produce an unauthorized carry. Thus if 99 was simultaneously struck in the units and tens columns both wheels might overrun so as to make a carry in both the tens and hundreds wheels, and show a total of 110 instead of 99. The most important of these stops operate on the column-actuators, and will be referred to later.

Improvement in Carrying: Claims 29 and 30. Referring to the cuts 5 and 5a it may be seen that there would be a loss of carry if, when the carry is being made, both the lower and higher order wheels are moving. As described by plaintiff's counsel:

"The thousands wheel might at one and the same time be receiving both an Impulse from a key of its own and an impulse from the carrying mechanism of the hundreds wheel; and if there were not some special means for preserving both impulses the lesser or carrying impulse might be swallowed up in the greater or key-driven impulse that such thousands wheel was receiving."

The patentee refers to this feature as follows:

"In order to prevent the loss or swallowing of the carrying movements in the other and generally larger movements of the numeral-wheels received from 243 F.-55

the impulse of the keys, which would occur if the carrying took place simultaneously with the key movements, I have devised means whereby the opera, tion of the carrying mechanism of the different denominations is caused to take place between the key-strokes in the same denominations and after such strokes have been completed and the numeral-wheels have moved in accordance therewith."

In securing this Mr. Felt also obtained another important result highly useful and entirely new, called the duplex key action or fluidity of key movement. This was the capacity of the machine for striking a number of keys in different denominations at the same time, without striking them absolutely together. That is, the key-action may be independent, or irregular and overlapping, thus giving the machine an elastic or fluid action. It is possessed by both plaintiff's and defendant's machines alike, and has been called by plaintiff's witnesses and counsel, "fluidity of keyboard action." How this new result is obtained by both parties will now be described; the vital question being whether defendant, in using different means and a different operation, has really taken an equivalent.

In order to show how Felt attained these objects modified figures of the patent, as shown in defendant's brief, are here reproduced. The mechanism is described by Mr. Felt with sufficient clearness:

"The sleeve 44 is also provided at opposite sides, as shown at Fig. 26, with two projections 71, each adapted to engage the under edge of a latch 73, pivoted on the cross-rod 48a. The latch is extended over and rests on the columnactuator of the denomination to which the carrying is to be done, and preferably on the pin 67 on the actuator, and a spring 99, already mentioned, draws the latch over onto the actuator. Normally the latch is out of engagement with the projections 71; but when any key of the column to which the carrying is done is struck the actuator of that column moves down, so that the latch drops into position, where it must engage the first or nearest one of the projections 71 as soon as the sleeve begins to turn. The sleeve is thus arrested before it gets fairly started or has performed any function, and continues to be held by the latch until the column-actuator has fully completed its upstroke after being depressed by a key. When the actuator thus returns to its normal position and as it arrives at the same, it lifts the latch through the contact of the pin 67 with the end of the latch, so that the engagement with the sleeve is terminated, leaving the sleeve free to turn under the power of the carrying-spring 43 and through the mechanism already described to operate its numeral-wheel through a one-tenth revolution."

The inventor, having conceived his idea of improving his old machine by having the higher order actuators suspend the carry from the lower order wheels, and allow it to occur only after the driving stroke of the next higher actuator had been made, drew a number of specific and one broad claim in order to secure the legal benefit of his invention. Each of these claims contains five elements, the first four being substantially the same, and being old, but the fifth represents the new conception. Claims 29 and 30 follow:

1

"29. The combination of a series of denominational numeral-wheels, a series of column-actuators operating said wheels, a series of keys for each actuator, and a carrying mechanism for each wheel, and means whereby the several carrying mechanisms may be temporarily controlled by the next higher actu

ators.

30. The combination of a series of denominational numeral-wheels, a series of column-actuators operating said wheels, a series of keys for each actuator, and a carrying mechanism for each wheel, and means whereby the actuator of a higher denomination may delay the carrying from a lower denomination until it has completed any movement imparted to it by the keys."

Claim 30 specifically represents the actual invention described in the specification, and claim 29 may be properly construed to cover all variations and equivalents of the five elements going to make up the real invention.

The mechanism of the delaying latch of the Felt machine has been already described, in connection with the patent drawings. The "inventive concept," or underlying and fundamental principle of the invention, was thus previously described in the specifications. After referring to his own prior art machines, Mr. Felt proceeds:

"A third objection to this class of calculators has been that they are liable to add incorrectly if the operator strikes two or more keys of different denominations simultaneously, because under such circumstances the carrying is often lost in the movement imparted directed to the register-wheels by the keys, and by reason of this fact it has not heretofore been possible to operate the machines by striking a plurality of keys simultaneously. Obviously a machine in which correct results can be obtained by striking two or more keys in different denominational series at a time will enable the operator to increase the speed of his calculations very materially, and by my present invention I not only obviate all danger of miscalculations from this cause, but produce a machine well adapted to permit the habitual striking simultaneously of a plural ity of keys."

"In order to prevent the loss or swallowing of the carrying movements in the other and generally larger movements of the numeral-wheels received from the impulses of the keys, which would occur if the carrying took place simultaneously with the key movements, I have devised means whereby the operation of the carrying mechanism of the different denominations is caused to take place between the key-strokes in the same denominations and after such strokes have been completed and the numeral-wheels have moved in accordance therewith. This feature of the invention will now be set forth."

And the patentee then proceeded to describe the mechanics of the invention in the words quoted on an earlier page.

[1] Since defendant does not use the delaying latch the question is thus presented as to the effect of describing the inventive concept or idea, claiming it as thus described, as in counts 28 and 30, and then attempting to broaden it by a more general count, as in claim 29. This situation has often come before the courts, and the governing rule well expressed by this court, and by Judge Colt, speaking for the Court of Appeals for the First Circuit. In Mossberg v. Nutter, 135 Fed. 95, 99, 68 C. C. A. 257, 261, Judge Colt said:

"In approaching a patent, we are to look primarily at the thing which the inventor conceived and described in his patent, and the claims are to be interpreted with this particular thing ever before our eyes. In confining our attention too exclusively to a critical examination of the claims, we are apt to look at them as separate and independent entities, and to lose sight of the important consideration that the real invention is to be found in the specification and drawings, and that the language of the claims is to be construed in the light of what is there shown and described."

In this court, in State Bank of Chicago v. Hillman, 180 Fed. 732, 104 C. C. A. 98, Judge Grosscup said:

"The question of law presented, then, is this: Can the patentee rightfully include in his claims something that does not emerge from the description? Can a patentee describe something to the world in his letters patent that means just that thing or its equivalents and nothing else, and, having claimed that, claim in addition something not thus described and not its equivalents? We think not. The description is required to set forth the invention in such full, clear, concise, and exact terms as to enable any person, skilled in the art to which it appertains, or with which it is most nearly connected, to make and

use the same; and the claim is to enable the public to know the bounds and scope of the invention 'thus disclosed'; but 'any claim which is broader than the described invention is void, even where that invention is valuable, and could have supported a valuable claim.' Walker on Patents (4th Ed.) § 177, citing Edison v. American Mutoscope Co., 114 Fed. 934, 52 C. C. A. 546." "There is nothing in Winans v. Denmead, 15 How. 330, 14 L. Ed. 717, or the Paper Bag Patent Case, 210 U. S. 405, 28 Sup. Ct. 748, 52 L. Ed. 1122, brought to our attention since the argument, nor in any of the rules of law cited (that the claims of every patent should be construed, if possible, to cover and protect the actual invention made by the patentee, and should not be restricted to the particular form of device disclosed in his patent, if other forms may embody it.' or that 'the patentee's claim is the "measure of his invention," or that 'where the claims of a patent are clear and unambiguous, there is no room for construction') that contravenes what has just been said; for what is said in both of these cases, and in all of these rules, is based on the fact that the inventive concept is disclosed in the description, whatever may have been the mechanical form that such concept subsequently took. Certainly it was not intended by these cases or these rules that an inventive concept, that is separate and apart from the one embodied in the description, should become a part of the patent simply by being included in the claims.”

The Hillman Case was approved by this court in Stevens v. Mitchell, 220 Fed. 455, 136 C. C. A. 283, and the Supreme Court announced the same doctrine in Snow v. Lake Shore & M. S. R. Co., 121 U. S. 617, 7 Sup. Ct. 1343, 30 L. Ed. 1004. To the same effect are Celluloid Co. v. Arlington Co., 52 Fed. 740, 3 C. C. A. 269; Whitaker Cement Co. v. Huntington Dry Pulverizer Co., 95 Fed. 471, 37 C. C. A. 151, and Jewell Filter Co. v. Jackson, 140 Fed. 340, 72 C. C. A. 304.

Thus the gist or spirit of the invention was to cause the carry to occur only between actuator strokes, and to be held up and delayed until the next higher actuator has come to rest after an impulse of its own. This is the "law of the machine" and the prime object of the invention; but the operation is entirely foreign to defendant's device, in which the carry is not delayed, but occurs as well during a higher actuator movement as at any other stage.

Plaintiff's position is that claim 29 covers any and all means by which the carrying mechanism is temporarily controlled in any degree by the next higher actuator; and that unless this meaning be given to claim 29, the latter cannot be distinguished from claim 30. In support of this plaintiff's counsel appeal to the well-understood theory of claim differentiation described by Judge Baker in Lamson Consolidated Store Service Co. v. Hillman, 123 Fed. 416, 59 C. C. A. 510, to the effect that separate claims are not to be construed as identical unless fairly unavoidable. "To construe claim 8 as being the same as either claim 10 or claim 11 would be to declare claim 8 void as a duplication. Such a course should not be pursued unless it cannot fairly be avoided." Baker, C. J., in Kennicott Co. v. Holt Ice & Cold Storage Co., 230 Fed. 157, 144 C. C. A. 455.

[2] The rule is of course well established that the courts will always endeavor to distinguish the several claims of a patent, one from another, and that where a patent contains two similar claims the difference in the wording of the two claims will be given effect if possible, and the more broadly stated claim will be construed more broadly than the narrowly stated claim, if it can be done within the limits of the