SANBORN, Circuit Judge,
after stating the facts as above, delivered the opinion of the court.
The bill in this case charges an infringement of the five claims of letters patent No. 414,0(59, issued to Peter II. Murphy on August 3, 1889, for an improvement in car roofs. The roofs which the appellee made and sold, and which, the bill charges, infringe the claims of this patent, were constructed in accordance with the specification which forms a part of letters patent No. 446,780, issued to Curtis M. Jennings on February 17, 1891, for an improvement in similar roofs. The object which each of these patentees sought to attain was the construction from sheets of metal of a covering for a roof that would be impervious to, and would shed, water. The special evil which they were trying to remedy was the leakage likely to result from joining the sheets, and from fastening them to the boarded roof by nails or screws which would pass through punctures in the exposed surface of the metal. Murphy asserts by his patent that he accomplished this purpose and remedied this evil by constructing his metal covering in this way: lie fastened upon the boarded or sheathed roof metal strips shaped like an inverted letter T. He placed one of these strips along the ridge of the roof, and others on its sides, so that they would extend from the ridge to the eaves. He placed those upon the sides of the roof at such distances apart that the sheets of. metal, when prepared for laying, would exactly cover the space between them. lie fastened these strips securely to the roof by nails or screws driven through the flanges into the roof. He made his sheets of suitable lengths to extend from the ridge to the eaves of the car, and bent their respective edges into the form of flanges, so that, when laid, the upturned edge of one sheet would lie against, extend to the top of, and closely fit one side of, each strip, and the flange, in the form of an inverted U, upon the plate upon the opposite side of each strip, would slip over and completely cover tin; upright flange of the metal strip, and the upturned edge of the sheet on the other side of it. He fastened the sheets by rivets which passed through the flanges of the sheets and the upright flanges of the strips. He covered the openings at the points of intersection of the joints upon the sides of the roof with that upon the ridge with a cap provided with four channels, which received, and closely fitted over, the intersecting flanges. In order to provide means for the attachment of the running board to the ridge of the car, he provided some of these caps with screw studs, which passed through the sleeper to which the board is ordinarily secured, through the cap, and through the running board. Jennings, in his construction, discarded the metal strips entirely, and they are not found in the roofs made and sold by the appellee. He made the joints between his sheets of metal at the ridge and on the sides of the roof, and fastened them to it in this way: He bent one' edge of his sheets into the form of an inverted V, so that a portion of the sheet protruded beyond the bend, and formed a nailing flange. He fastened this sheet directly to the boards of the roof by nails or screws which extended through this protruding flange and into the roof. He bent the edge of the adjacent sheet so that it would [972] lie against, extend to the top of, and closely fit the side of, the V-shaped flange upon the sheer adjoining, and in this way completely covered the nailing flange. Over the flanges of these adjacent sheets he placed a metal cap in the form of an inverted Y-shaped strip, which completely covered these flanges, and was fastened in its place by rivets through its sides, a ad through the rising flanges of the adjacent plates. He covered Hie points of intersection of the joints upon the sides of the roof with that upon the ridge with four-way caps, and provided for fastening the running board upon the caps with bolts.
It may be conceded that i! Murphy had been the first to invent a covering of sheets of metal for a roof, or the first to construct and describe a joint between such sheets impervious to water, or the first to cover the intersecting joints of such sheets with a water-tight metal cap containing channels to receive and cover the joints, or the first to invent screw studs or bolts to fasten together detached pieces of wood and metal, uml if he had properly claimed any of these inventions in his application for his patent, the construction of Jennings would have contained a mechanical equivalent of such an original invention, and would have been an infringement upon it. On the other hand, if coverings for roofs constructed of sheets of metal had been described and used time out of mind before this patent was issued to Murphy; if devices for joining metal sheets, for fastening them to the roof, for covering the intersections of the joints, and for fastening a board upon a metal surface by a screw or bolt, which together accomplished the object of making a tight and durable roof, and which differed from those described by Murphy only in slight details of construction, — had been known and used for years before he had applied for his patent, then so radical a departure from the construction he described and claimed, as the entire omission of the metal strips by which he secured his covering to the roof, and over which he made his joints, may relieve the ap-pellee from the charge of infringement. The claims and specifications of every patent must be read and construed in the light of á knowledge of the state of the art when it was issued. A patent to the original inventor of a machine or construction, which first performs a useful-function, pro tects him against all machines and constructions that perform the same function by equivalent mechanical devices. But a patent to one who has simply made a slight im-. provement on devices that perform the same function before as after the improvement is protected against those only which use the very improvement he describes and claims, or mere colorable evasions of it. McCormick v. Talcott, 20 How. 402, 405; Stirrat v. Manufacturing Co., 27 U. S. App. 13, 42, 10 C. C. A. 216, 217, and 61 Fed. 980, 981. The question of infringement or noninfringement in this case, as in every case, must be determined under this rule by the limitations placed upon the patent by the state of the art when it was issued, and by the specification and claims of the inventor. It is common knowledge that roofs were made impervious to water by covering them with sheets of metal, arid that screw studs and bolts were used for fastening together wood and metal long prior to the year 1889. [973] A metal cap with, channels to receive and cover the jointed flanges of metal sheets upon roofs at the points of their intersection appears from the evidence to have been an old device. One of the witnesses testified that when he learned Ms trade, in 1849 or 1850,he was taught to use a four-way cap of this character to cover the point of intersection where four standing seams came together at the ridge of a sheet-iron roof. Such a cap was found on the St. Louis courthouse, where it had been in use for this purpose since 1882. Fourteen patents for improvements in the method of constructing metal roofs of buildings, and two for improvements in the construction of metal car roofs, all issued anterior to the date of Murphy’s patent, illustrate the state of the art in this case. The suggestion that patents for improvements in the construction of metal roofs of buildings are immaterial here, and do not illustrate the state of the art of constructing metal roofs of cars, is not persuasive. The art of covering the roof of a car with sheets of metal is so nearly if not completely identical with that of covering a house with the same metal, that there could be no invention in appropriating the method or improvement found in the one to usd in the other, unless some radical modification was required to adapt it to the new use. All the anterior patents for improvements in metal roofs, whether of buildings or of cars, fairly illustrate the state of this art, and are entitled to consideration in this case. They portray many devices for forming the joints between the sheets of metal, and for securing the sheets to the wooden sheathing of the roof without the use of nails or ■screws that pass through the exposed surface of the covering. In some of them metal strips are described, and their use is recommended. In others they are not mentioned or used. In the specification of letters patent No. 1,321, issued on September 11, 1839,, to Peter Naylor, for an improvement in the manner of covering the roofs of buildings with sheets of metal, he describes, as a part of his invention, bars of metal which, he says, (nay be placed edgewise directly upon the planking or sheathing of the roof, and should extend from the ridge to the eaves. He describes a method of making the joints between the sheets so difficult to distinguish from that portrayed in the patent to Murphy that we quote it:
“Over these bars or plates, the edges of the covering of sheet metal is to he lapped, the edge of one sheet rising up on one side of said bars so as to reach the upper edge, and the edge of the next sheet constituting a saddle which laps over on both sides of the bar, embracing’ the first-described bent edge of the next contiguous sheet. The sheets so placed are to be united firmly to the bars, e, e, e, by rivets passed through the whole, at suitable distances apart.”
In the specification of letters patent No. 165,113, issued June 29, 1875, to Samuel T. G. Morsell, for improvements in sheet-metal roofing, there is a description of ribs of wood extending from the ridge to the eaves of the roof, fastened to the sheathing by screws or other suitable means; sheets of metal with upturned edges lying flat against, and extending to the top of, the vertical sides of the ribs; caps of sheet metal bent to fit over and cover the ribs and the upturned edges of the sheets on their sides; and screw bolts which pass completely through the sides of the caps, the upturned edges [974] of the sheets lying against them, and the ribs themselves, and thus secure them all in place.
In the specification of letters patent No. 886,316, issued on July 17, 1888, to Samuel B. Hawthorne, for improvements in roofing, there is a description of a metal rib, in the shape of an inverted T, fastened to the roof by nails driven through the flanges. This specification so nearly describes the. “angle strips” of Murphy, that we quote from it, omitting the letters of reference:
“This rib is made of sheet metal folded in the manner shown, so as to give a dovetailed shape to the upright portion, and with side flanges, by aid of which the rib is securely fastened to the roof boarding by screws or nails driven through holes punched in said flanges.”
This specification describes a joint between the sheets of metal, made by fitting their upturned edges closely to the sides of these ribs, and covering both the ribs and the upturned edges with metal caps made of dovetailed form to fit the ribs, slid longitudinally over them and the upturned edges of the plates, and made to hold them all firmly in place by tightening strips driven in between the tops of the ribs and the caps.
In the specification of letters patent No. 143,471, issued on October 7, 1873, to Eollin A. Smith, for improvements in metal roofing, there is a description of triangular strips nailed firmly to the roof of the building, lengthwise thereof, and at a distance apart equal to the width of the plates, and a description of joints between the sheets of metal made by bending their edges in the same way described by Murphy. According to this specification, the edge of the plate adjacent to one side of each of these strips is bent at an obtuse angle, so that it will fit closely and" extend to the top of the strip, while the edge of the sheet upon the other side of it is bent in the form of an inverted V, which covers the strip and the upturned edge of the plate which lies against it upon the opposite side. The sheets are held firmly in place by nails driven through their edges where they lap over each other into the strips.
In letters patent No. 218,085, issued July 29, 1875, to Griffith B. Thomas, for improvements in roofing, there is a description of a covering of sheet metal, which is a 1 (ached to the roof by clips of metal, without the use of strips of any kind. The joints are formed by turning up one edge of a sheet., and covering it by a cap made by bending the edge of the adjoining sheet over it in the form of an inverted U.
In the specification of letters patent No. 95,732, issued on October 12, 1869, to Franklin Boys, for an improvement in metallic roofing, there is a description of a joint between the metal sheets formed by bending the edge of one of the plates into an angle shape with a protruding flange, through which nails are driven to fasten it in place, and covering the nailed flange, and fastening the next adjacent plate by sliding its correspondingly bent edge over the edge of the preceding plate.
Perhaps the testimony and the antecedent patents to which reference has now been made sufficiently disclose the state of the art when the patent to Murphy wa- issued to enable us to reach a cor[975] rect conclusion in this case. They demonstrate the fact that every element in the five combinations claimed by Murphy was old. His “angle strips” in the form of an inverted T exactly copy, and perform the function of, the metal ribs of Hawthorne. They are the mechanical equivalents of Naylor’s bars of metal, Morsell’s ribs of wood, and Smith’s triangular strips. His method of fastening Ms sheets of metal to his angle strips and Ms joints between Ms sheets copy and perform the function of the method and joint described by Naylor, and are the mechanical equivalents of those described by Morsell, Hawthorne, and Smith. His four-way cap has been in notorious public use, to perform the function to which he assigns it, since 1882; and his stud screw, so long that the memory of man runneth not to the contrary. If there is anything new or patentable in the construction described by Murphy, it is not in any of the elements he has used, but in the novelty of their combination. His patent must stand, if it can be maintained at all, on the principle that a new combination or arrangement of old or well-known ingredients, by which a new and useful result is attained, may be a patentable invention. Griswold v. Harker, 27 U. S. App. 122, 150, 10 C. C. A. 435, 437, 438, and 62 Fed. 389, 391; Thomson v. Bank, 10 U. S. App. 500, 509, 3 C. C. A. 518, 520, 521, and 53 Fed. 250, 252, 253; Seymour v. Osborne, 11 Wall. 516, 542, 548; Gould v. Rees, 15 Wall. 187, 189. But the appellant is met here by the unquestioned rule that the absence from a device or construction, that is alleged to infringe, of a single essential element of a patentable combination of old elements, is fatal to the claim of infringement. Building Co. v. Eustis, 27 U. S. App. 693, 712, 13 C. C. A. 143, 148, and 65 Fed. 804, 810; Hailes v. Van Wormer, 20 Wall. 353, 372; Bragg v. Fitch, 121 U. S. 478, 483, 7 Sup. Ct. 978. The angle strips of Murphy are absent from the metal roof described by Jennings, and from those made by the appellee. Murphy made these strips an indispensable and chief element of each of the five combinations he claimed. His general description of Ms invention in the second paragraph of Ms specification reads;
“This invention relates to a metal roof for railroad cars, the metal plates being secured to vortical metal ribs by horizontal rivets passing through upright flanges on the plates.”
The first element of Ms combination that is described in Ms specification is these angle strips, and they constitute the first element of each of the five combinations to which he has limited his claims. These claims commence thus:
“(1) The combination, in a roof, of the angle strips, 3, adapted to he secured to the sheeting, 1, and having a flange, 5, and * * *. (2) The combination, in a roof, of the angle strips, 3. with upright flanges, 5, and * * *. (3) The combination, in a car roof, of the angle strips, 3, the plates, 6, having the flanges, 7, 8, 10, and 11, and * * *. (4) The combination, in a roof, of the angle strips, 3, adapted to attachment to sheeting 1, and * * *. (5) The combination, in a car roof, of the angle strips, 3, adapted for attachment to the sheeting, 1, the plates, 0, with marginal flanges adapted for engagement with the strips, 3, and * *
The state of the art when this patent was issued clearly deprived the patentee of the benefit of the application of the principle of mechanical equivalents to the old elements of Ms combination. The [976] application of that doctrine to those elements would show that his use of each of them had been anticipated by prior use aiid prior patents. The only patentable novelty in his invention was the novelty of his combination of these elements. He made the flanged angle strips or ribs, by the use of which he formed the joints between his sheets of metal and fastened them to the roof, an indispensable element, and the principal element, of all the combinations he claimed. This element is entirely wanting in the roofs manufactured by the appellee, and in ¡he specification forming a part of the patent to Jennings under which they were made. The roofs manufactured and sold by the appellee cannot, therefore, be held'to infringe any of the claims of the natent to Murphy. This conclusion renders it unnecessary to consider the novelty or patentability of the combinations which he claimed in this patent. The decree below must be affirmed, with coses, and it is so ordered.,