said carriage, a flexible power-transmitter connecting said cutting tool with a source of power, and a sliding work support, substantially as and for the purposes set forth."

The machine used by the defendant, constituting the alleged infringement, is made in substantial conformity with letters patent No. 571,535, issued to E. Lochman November 17, 1896. The answer denies infringement of the Smith and Post patents, denies invention in either patent, and sets up numerous patents and publications by way of anticipation.

The Lochman device is shown in vertical section (Fig. 1) and side elevation (Fig. 2) as follows:

E. H. Bottum, for appellant.

Lysander Hill and Curtis T. Benedict, for appellee.

Before JENKINS and BAKER, Circuit Judges, and SEAMAN, District Judge.

SEAMAN, District Judge (after stating the facts as above). The appellant's bill alleges ownership and infringement of two letters patent, Nos. 443,802 and 447,796, both issued to Thomas L. Smith and Paul W. Post, as inventors, and the answer raises the issue of title..

Evidence of title rests on an instrument purporting to be made by the patentees, bearing date February 6, 1888, and recorded in the Patent Office February 24, 1888, which is not printed in the transcript of record, but is referred to and expressly offered as testimony on behalf of the appellant, and a copy appears subsequently certified from the court below. No objection is made in respect of title to the first mentioned, No. 443,802, but the appellant's title to letters patent No. 447,796 is challenged. We are of opinion that no sufficient title appears to sustain the bill for infringement of the latter patent. The purported assignment referred to grants "exclusive right to manufacture, use and sell or lease to be used the carving machines for which said Smith and Post have lately applied for letters patent," under application of October 3, 1887, serial number 251,296, which describes only the application on which No. 443,802 issued. The application for No. 447,796 was filed April 9, 1888, and the patent was issued March 10, 1891, both dates being subsequent to this grant; but the assignors "further agree and bind themselves that in case they shall by invention or purchase become the owners of any invention in or improvement upon carving machines," or for analogous purposes, "they will transfer and assign a like exclusive right," and the intention is stated "to confer on the Milwaukee Carving Company the exclusive right" to use any carving machine for which the assignors "have procured or may procure any patent rights whatever." While the terms of this agreement in reference to subsequent "invention in or improvement upon carving machines" are probably applicable to the device shown in patent No. 447,796, and may be enforceable between the parties, as authorized in Littlefield v. Perry, 21 Wall. 205, 226, 22 L. Ed. 577, it is plain that such agreement is executory only, and not an assignment, within the statute, so that no legal title is conferred. The subject-matter was not then in being, was incapable of sale and delivery, and, however binding the contract. was upon the inventors to grant the right or title in their subsequent invention, it is not a legal assignment, and, at the utmost, confers upon the appellant a mere equity, with the legal title in the patentees. 2 Robinson on Patents, § 771; Curtis on Patents (4th Ed.) §§ 171, 172; Regan Vapor Engine Co. v. Pacific Gas Engine Co., 49 Fed. 68, 1 C. C. A. 169. Suit by an assignee for infringement is authorized only when the assignment is complete within the statutory requirement. Waterman v. Mackensie, 138 U. S. 252, 256, 11 Sup. Ct. 334, 34 L. Ed. 923, and cases reviewed; Pope Mfg. Co. v. Gormully Mfg. Co., 144 U. S. 248, 251, 12 Sup. Ct. 641, 36 L. Ed. 423. The rights of the patentees cannot be adjudicated in their absence, and the claimant of an equitable title or interest cannot maintain suit for infringement upon such title alone. 3 Robinson on Patents, § 1099, and cases cited; Stimpson v. Rogers, 4 Blatchf. 333, Fed. Cas. No. 13,457.

The bill rests, therefore, upon the primary patent, No. 443,802. This patent embodies the combination under which the appellant makes a useful carving machine for duplicating carvings from a model, and has achieved success in the sale of rights to use the machines. The questions arising are not materially simplified by thus eliminating. the subsequent patent, No. 447,796, from the issue of infringement.

The appellee's machine is made in conformity with another and later patent, accomplishes like results by combining old elements, and the main controversy is whether the combination so employed infringes. the combination of old elements shown in patent No. 443,802.

While the defense of anticipation is set up against this patent, and some 57 prior patents, domestic and foreign, are introduced in its support, no patent or publication appears showing the same combination of elements or adaptability for like results. The nearest approach to the combination is found in certain foreign patents cited by the expert on behalf of the appellee, namely, Hawkin's English patent, No. 2,735, dated in 1803, on "machinery for writing, painting, drawing, ruling lines," etc.; Robertson's (1837) English patent, No. 7,363, on "machine for sculpturing marble, stone, and other substances"; Conte's (1845) English patent, No. 10,850, for "carving machine"; and La Maire's (1852) French patent, No. 8,266, for "sculpturing stone, marble, wood, and other materials." These patents are of value as examples of the prior art, both in carving machines and for analogous purposes, for interpretation of the claims; but for the present purpose it is sufficient to remark that neither embodies the combination shown in patent No. 443,802, leaving the distinctions to be pointed out when the scope of invention is considered. So in reference to the numerous other patents introduced-from the field of wood carving and the various fields of working in or engraving on wood, metals, stone, and glass-while many machines appear for wood carving, including devices for duplicating carvings, none shows the combination embodied in the present patent, nor identity in the results of the united elements. The elements appear severally in one or another of such prior patents, but are not all united in either. These patents furnish evidence of the prior state of the art, but do not deprive the new combination of patentable novelty. Parks v. Booth, 102 U. S. 96, 103, 26 L. Ed. 54. Nor are the claims in question subject to the objection urged on behalf of the appellee that it is "a mere collocation or aggregation of old elements," as it is plain that the several elements are brought into co-operation and thus "perform additional functions and accomplish additional results," forming a true combination. I Robinson on Patents, § 155.

Impressed with the undoubted merit of the Smith and Post invention, the question whether it is infringed by the appellee's machine, made under Lochman's later patent (No. 571,535), has presented difficulty in its solution. The rule is well settled, however, that the grant of a subsequent patent raises a legal presumption of patentable difference from the earlier invention (Miller v. Eagle Manufacturing Co., 151 U. S. 186, 208, 14 Sup. Ct. 310, 38 L. Ed. 121; Kokomo Fence Machine Co. v. Kitselman, 189 U. S. 8, 23, 23 Sup. Ct. 521, 47 L. Ed. 689), and we are convinced as well that substantial difference in the combinations is established as matter of fact.

It is true, as stated by one of the experts, that both machines are "founded on the scheme of tools and tracer carried in a freely moving articulated frame, so that the tools and tracer can be moved freely in every direction, and the tools duplicate the motions of the tracer; and on driving mechanism for imparting motion to the tools; and on

the model and stock carried in a sliding work-holder; and on pivoted. vibrating frames and jointed parallelograms as a means for permitting the desired freedom of motion." But these features individually are not novel-as they appear in numerous prior patents-and therefore not patentable, except as employed in a new combination. Both machines duplicate carvings from a model by means of a tracer and cutting tools which are so mounted and connected "that the cutting tools will duplicate every motion of the tracer, however slight or whatever its direction." The appellant's tracer and cutting tools operate vertically, so that the model is placed on the work table under the tracer, and the blanks to be carved are placed under the cutting tools, while the appellee's tracer and tools operate horizontally, and the model and blanks correspondingly occupy a vertical plane-a change which is not merely colorable, but due to a difference in the system of parallel motion, and having distinct advantages in operation. The mechanism of each provides parallel motion, "so that as the tracer is passed over the model, and brought into contact with each point of its surface, the cutting tool will cut away from the blank all surplus material, thus leaving a duplicate of the model." Both accomplish undercutting through free tilting movement of the toolsthough differing in the means and degree of such tilting operation— and this feature of undercutting constitutes the distinct advance in the art made by the Smith and Post device over all prior carving machines. The appellant's (Smith and Post) means to this end are (1) two parallel motions of the link or pantograph construction, one controlling the horizontal movement of the tools, while the other controls their perpendicular movement; and (2) the gimbal-joint connection of tools and tool carriage, whereby the cutting tool has free movement independent of the carriage movement. Also, "for imparting motion to the cutting tool," revolving at great speed, a flexible shaft is used, thereby permitting the tool to respond to the movements. of the tracer without interference. The appellee's (Lochman) machine, on the other hand, has a parallel motion device of the wellknown elbow-joint or door system, and does not have the two distinctive horizontal and vertical motions of the appellant's device, nor its essential element of a gimbal-joint connection; and, instead of the flexible shaft, the appellee uses a belt-and-pulley device to revolve the cutting tool. Thus both machines, generally speaking, present a combination of old elements for like purpose. Both utilize the parallel motion idea of means for duplicating carvings, and both achieve the new carving machine result of undercutting. Upholding the prior patent, however, as disclosing useful invention for this important achievement, establishes therein no monopoly in the result, nor in the use severally to that end of well-known elements which enter into the combination. The patent is granted for the combination, as "the particular means devised by the inventor by which that result is attained," and the patentee is entitled to protection against any use of the same combination of elements, combined in the same way, so that each element performs the same function, or against substantially the same use with deviations which are merely colorable. But each of these well-known elements remains open to the use of the subse