The fact that the two chemical-treatment tanks are separate is not here emphasized as it has been before, although perhaps it is implied. When, however, we come to claim 11, we find less ambiguity. The language is:

The combination of a single tank containing the chemical reacting compartment and an upward flow settling compartment with a series of independent gravity filters,

which filters are then specifically described, and their function is pointed out. The question then is: Should this claim, because it refers to "the compartment," be confined to the specific form of compartment which has been made the subject of previous claims, and is here not mentioned? We are satisfied that the patentee thought he had invented a new improvement in filters which would be especially useful in connection with his complete apparatus, but was also useful in combination with any treatment and settlement tanks, and that he intended by his claim to protect the right to use his form of filter in combination with his general type of apparatus. The reference to the filter is and must be considered as specific; the reference to the treatment-tank is apt and suitable to be and should be considered as generic. The claim and the structure it fairly imports ought not to be sacrificed to the words found in other parts of the grant.

(5) Another analogous consideration leads to the same result. It is only applying to a patent the ordinary rules of construction applied to other grants, to say that, in determining whether a given element should be considered as present with a limiting effect in a claim in that respect ambiguous, we should observe the occasion or the necessity for its introduction by the claim draftsman. If its presence was necessary to distinguish the claim in point of patentability from the prior art or in point of effect from the other claims, it should be implied; but if it can be of no use in either of these particulars, it should not operate as a limitation. Of course, we are speaking only of ambiguous claims and not of those where the claim language requires the limitation." Applying this formula, claim 11 must be treated as calling only broadly for the chemicaltreating compartment as a unit, distinguished from the settling-compartment; the characterizing thought of the claim had to do with the presence in this general combination of Greth's particular improvements in filters. The filter received its water from the top of the settling-tank; the settling-tank received its water from the bottom of the treatment-tank, and, necessarily, from the last treatmenttank, if there was more than one; the treatment-tank, broadly consid

• Ryder v. Schlichter, (C. C. A., 3; 126 Fed. Rep., 487; 61 C. C. A., 469;) Wagner v. 'Wyckoff, (C. C. A., 2; 151 Fed. Rep., 585; 81 C. C. A., 129.)

Keystone v. Phanx, (C. D., 1877, 384; 2 O. G., 980; 95 U. S., 274; 24 L. Ed., 344;) Cimiotti v. American, (C. D., 1905, 729; 116 O. G., 1452; 198 U. S., 399; 25 Sup. Ct., 697; 49 L. Ed., 1100.)

ered, was a proper element of the combination, because thereby the water was given ultimate character affecting its conduct in the settlement-tank; but there could be neither inventive thought nor patenable novelty in adding to this combination one or two or ten tanks in which the water had been treated before it came to the treatmenttank from which it passed to the settlement-tank. There was therefore no occasion for Greth to include in this claim the preliminary, separate lime-treatment tank; every presumption must be that he did not unnecessarily limit his claim; and such presumption must prevail where, as here, the selected language is not at all inconsistent with the broader interpretation.

Still further confirmatory of this construction is what happened in the Patent Office. Claim 11 is the evolution of original claim 16, which was drawn merely to the combination of a tank and Greth's battery of independent-unit filters with means for separately cleaning each. This was rejected, because anticipated by separatelyoperating filters in connection with the pond or river used for a city water-supply. Greth then amended by identifying his tank as—

a single tank containing the chemical reacting compartment and an upward flow settlement compartment,

and the claim was then allowed. There is here no intimation that the Examiner required Greth, or that Greth intended, to confine his claim to a device having two separate chemical-reacting compartments. It is true, he said, in making this amendment:

The two claims (10 and 11) as now drawn, are confined to the exact structure and are different from the prior art in the following particulars: The washing of the filters does not interrupt the flow through the tank, and all the filters are fed only from the top overflow from the tank and not under variable pressure; the filters are independent and are carried on the tank itself, which is necessary to the unity and simplicity of the apparatus aimed at. The filter per se is not supposed to be new, but it has a peculiar function as modified and adapted to coöperate with this tank and other filters of a series in a continuous flow single tank system.

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(6) This statement that the claim was confined to the exact form" falls distinctly short of making either an estoppel or a conclusive admission as to the meaning of the claim in the respect now under discussion. It is not an estoppel, because Greth was not required to put the two separate treatment-tanks into this claim in order to get his patent allowed; it is not a conclusive or at all persuasive admission because the whole context shows he did not have this point in his mind. The claim was confined to the (comparatively) exact form and distinguished from the prior art in all the various particulars which he proceeds to enumerate, but none of

8

8 Bundy v. Detroit, (C. C. A., 6; 94 Fed. Rep., 524; 36 C. C. A., 375;) Wayne v. Benbow, (C. C. A., 8; 168 Fed. Rep., 271; 93 C. C. A., 573;) Sly v. Russell, (C. C. A., 6; 189 Fed. Rep., 61; 110 C. C. A., 625.)

them have anything to do with the question of one treatment-tank or two.9

(7) There remains only the question whether claim 11 discloses patentable invention as compared with the prior art. We have construed this claim as calling, somewhat broadly, for the combination in one continuous-flow structure of the chemical-treatment (downward-flow) compartment, the upward-flow settling-tank and Greth's battery of overflow-filters. So construed, its only distinction from the Patterson English patent or the De la Coux device described in a French publication in 1900, is in the form and operation of the filter. Each of these devices had a single filter at the top of the tank and fed by overflow from the tank. Patterson had a sand filter-bed through which the water passed downwardly. De la Coux had a filter-bed through which the water passed upwardly, being first carried in a passageway from the top of the tank to the bottom of the filter. Neither of these disclosed any means of cleaning the filterbed, except by stopping the operation of the entire structure. The idea of a group of filters each of which could be cut out independently without affecting the work of the others was broadly old, but had been applied nowhere except in city water-supply systems or for analogous uses where the lake, river, or pond was the settlementbasin and the water was brought therefrom in conduits to the filters. It had never been applied as a part of a unitary structure in the treatment of water to produce a comparatively small continuous flow for industrial purposes. When so united with such a structure, in a compact, unitary, well-designed, and effective form, it makes a new combination, and it produces a result different from what had before been accomplished. It seems now a simple thing to substitute the battery of independently-cleanable filters for the single filter; if it had been a common expedient in analogous situations to substitute one for the other, we would have a different question; but this substitution involved both the thought and considerable necessary structural adaptation. The patent has been granted, the defendant by adoption has certified its usefulness, and the lack of anything more than mechanical skill is not clear enough to justify us in saying that there was lack of invention.10 Our only difficulty in reaching this conclusion arises because De la Coux, in the French publication, in 1909, and referring to his upward-flow filter, said:

A filter formed of an annular space concentric with the outer wall of the center may be divided into two parts to facilitate the cleaning, without stopping the purification.

9 Vrooman v. Penhallow, (C. C. A., 6; 179 Fed. Rep., 296; 102 C. C. A., 484.)

10 For illustrations of rule that adding an element to an existing structure may or may not be invention, see Kellogg v. Dean, (C. C. A., 6; 182 Fed. Rep., 991; 105 C. C. A., 545;) Houser v. Starr, (C. C. A., 6; 203 Fed. Rep., 264; 121 C. C. A., 462.) See, also, Sly v. Russell, (C. C. A., 6; 189 Fed. Rep., 61; 110 C. C. A., 625,)

This was a suggestion of the very thing which Greth did, and it was in connection with the otherwise complete combination use by Greth; but we think it only a suggestion. Neither drawing nor description told how to do it. Such matter as this must be either a full disclosure equivalent to a full anticipation, or else it is properly classifiable as a suggestion. Greth adapted and combined together the treatment and settlement tanks of De la Coux, the separableunit idea of the city water systems, and the cleaning by reverse flow idea found in other filters. To do this, he devised suitable forms and arrangement for the entire unitary structure, and for the filtering apparatus, gates, and inlet and outlet pipes necessary. All had to be adapted to the combination. The fact that De la Coux suggested it might be done is not enough. It was no more efficient than the suggestion which, in Herman v. Youngstown Co., (191 Fed. Rep., 579; 112 C. C. A., 185,) we thought not enough to negative invention. The defendant is using the structure of claim 11, as we interpret that claim. Its structure embodies, just as Greth's device does, a gate shutting the filter off from the settling-compartment, a discharge-pipe carrying away to the sewer the overflow from the top of the filter when it is washed, and the ordinary outlet-pipe from the bottom of the filter, usually carrying away clear water, but which, by suitable connection, could be made to receive the washing-water and force it up from the bottom of the filter-bed. That the only time when its operation was observed by witnesses, defendant was cleaning one filter at a time, cut out from the settling-tank, by washing the same with a hose instead of by water reversed through the discharge-pipe, and considering that the defendant had the complete device capable of use, just as contemplated, by turning a valve or adding the water connection, is not vital. We think it did not escape infringement if it did in fact use the device only in a less perfect and more awkward way. The claim does not specify nor necessarily imply the precise method of cleaning.

The decree must be reversed and the record remanded, with instructions to enter the usual decree for injunction and accounting on claim 11, provided that, within thirty days after the filing of the mandate, complainant has made disclaimer under claim 10 according to the practice established in this circuit.11 The appellant will recover costs of this court, but not, up to this point, in the court below.1

12

11 Herman v. Youngstown, (C. C. A., 6; 191 Fed. Rep., 579; 112 C. C. A., 185.)
12 Houser v. Starr, (C. C. A., 6; 203 Fed. Rep., 264; 121 C. C. A., 462.)

[U. S. Circuit Court of Appeals-Seventh Circuit.]

KRELL AUTO GRAND PIANO Co. OF AMERICA v. STORY & CLARK CO.

et al.

Decided April 15, 1913.

206 O. G., 313; 207 Fed. Rep., 946.

1. PATENTS-VALIDITY-DETERMINATION ON DEMURRER.

A patent cannot be held invalid on demurrer to a bill for its infringement unless inevitably void either on its face or by reason of matters of such universal or common knowledge that the court may take judicial notice of them.

2. SAME-SAME-PATENTABLE COMBINATION.

A patent for a mechanism consisting of two or more elements is not necessarily invalid as an aggregation because there is no direct coaction between the elements where such coaction comes to produce a unitary result through the mediation of the operator or the operating force.

3. SAME-SAME-AUTOMATIC PIANO-PLAYER.

The Welin patent, No. 825,784, for an automatic playing attachment for musical instruments, is not void on its face either for lack of patentable novelty or as an aggregation of old elements.

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99

In one sense (which, in the interest of accurate terminology, might well be taken as the exclusive sense) aggregation in the law of patents means that the claims in and of themselves, independently of the prior art, show that the elements are incapable of coacting to produce a unitary result.

APPEAL from the District Court of the United States for the District of Indiana; Albert B. Anderson, Judge.

STATEMENT OF THE CASE.

Appellant filed its bill, in the usual form, to hold appellees as infringers of the Welin patent, No. 825,784, issued July 10, 1906, on application filed July 20, 1904, for an "automatic playing attachment for musical instruments." Appellees demurred on the grounds (1) that no patentable novelty is disclosed in the specification and claims, and (2) that the claims are for aggregations of old elements which have not been brought into patentable combinations. Upon the demurrer's being sustained, the bill was dismissed for want of equity; and this appeal resulted.

Drawings, description, and claims of the patent are as follows: This invention relates to that class of automatic playing attachments which are housed within the casing of the pianos to which they are applied.

The especial object of this invention is to combine the levers which control the automatic playing with the piano casing in a strong, compact, and convenient arrangement which will permit said parts to be entirely inclosed when the piano is to be played manually and while at the same time said parts will occupy comparatively little room within the casing itself.