
    STIRRAT et al. v. EXCELSIOR MANUF’G CO.
    (Circuit Court, E. D. Missouri, E. D.
    January 20, 1893.)
    No. 3,255.
    Patents — Limitation of Claims — Impkovemf.nts in Stoves.
    The Stirrat patent, No. 357,874, for an improvement in stoves, must, in view of the prior state of the art, and of the modifications of the claims in the patent office, be strictly limited to the construction described, which includes as one essential element a removable top plate, or long center, east hollow, or with a projection having a water passage through it. The patent therefore does not cover the idea of bolting a water pipe or water box to the long center for the purpose of cooling it, and giving h greater durability.
    Suit in Equity hy Robert J. Stirrat and others against the Excelsior Manufacturing Company for infringement of a patent.
    Fowler & Fowler, for complainants.
    Paul Bakewell, for defendant.
   THAYER, District Judge.

The file wrapper and contents of letters patent No. 357,874 show that when the application was filed the patentee (Robert J. Stirrat) supposed himself to he the inventor of the hollow long center for stoves and ranges. His sole claim was for “the long center of a stove or range, formed with a water passage or passages therein, communicating with induction and eduction pipes, substantially as and for tbe purpose set forth;” and in his specification he stated that his improvement consisted “in forming a water passage in the long center or centers, connected with, tbe water tank by suitable pipes;” and that tbe main purpose of thus casting tbe top plate or long center was to protect it from the action of beat, and to prevent it from becoming warped. In tbe first communication from tbe patent office tbe patentee was advised that tbe supposed new method of molding and using tbe long center of a stove as a water pipe, to render it- more durable, was not new; that both tbe top plates and long centers of stoves and ranges bad previously been molded with water channels, for tbe express purpose of distributing tbe beat, and preventing them from becoming warped. Vide U. S. letters patent No. 277,009, lines 40 to 45, inclusive. It would seem as though this first communication from tbe patent office ought to have satisfied tbe patentee that bis claims as an inventor rested upon a doubtful foundation, and that very little scope could be given to any claim which be might eventually succeed in having allowed. Other inventors bad already suggested tbe idea of casting tbe top plates of a stove hollow, and of permitting water to circulate .therein, for tbe purpose of protecting tbe plates, in a measure, from tbe destructive action of heat. But, as usually happens in such eases, tbe patentee persisted in bis efforts to obtain a patent on something, although bis main idea bad been anticipated. Having modified Ids specification by tbe additional statement that bis invention related “to those water-beating devices in which the water to be heated is caused to pass through tbe long center and a water-back,” and that bis improvement consisted “in features of construction” merely, be subsequently laid claim to “a combined long center and water-back consisting of a top plate, C, having tbe chamber C', horizontal pipe section, F', F", eduction pipe, G-, and induction pipe, F, substantially as set forth.” This claim was likewise rejected, as containing nothing substantially new; but eventually, and after further changes in the specification, a patent was granted, containing three claims, of which tbe first claim may be taken as a fair sample. It is as follows:

“Tlie combination, with tbe removable top plate of a cooking stove having a chamber therein, of an exit pipe leading from said chamber at one end of the plate, and an inlet pipe running parallel to the exit pipe, extending to the other end of the plate, and communicating with the chamber, substantially as described.”

Before tbe issue, however, tbe descriptive part of tbe specification bad been amended so as to state specifically that “tbe long center, C, is cast with a projection having a water passage through it almost from end to end.”

Tbe court has been thus particular in stating some of tbe proceedings in tbe patent office for tbe purpose of saying that, in view thereof, tbe complainants must expect a strict construction of tbe claims of their patent; and for tbe further purpose of showing that throughout those proceedings tbe patentee constantly described tbe long center as a hollow casting, which bad been so made for tbe express purpose of carrying water therein, and resisting tbe action of beat. When tbe application for tbe patent was filed, tbe pat-entee evidently believed that bis invention consisted in casting the long center of a stove hollow, so that it might be used as a water pipe or water channel. This was what he first claimed, and all that he claimed. Before the date of his application it had long been the practice to heat water in stoves and ranges by conducting a water pipe into the fire box of a stove or range, and bending it somewhat into 'the form of an oxbow. The only change which Stirrat suggested in existing and well-known devices for heating water in stoves was the use of the long center of a stove as a water channel in, lieu of the upper leg of the old oxbow pipe; and that this was the view entertained by the patent office is evident from the inferences given, and the correspondence that took place during the pendency of the application.

Under all of the circumstances, the court is of the opinion that the combination covered by Stirrat’s patent must be limited very strictly to a combination of such parts as his specification describes, and that one of the essential parts of the combination is a removable top plate, or long center, cast hollow, or with a projection having a water passage through, it. The margin of invention is very small when viewed in connection with the state of the art at the time the Stirrat patent was issued. The patent office in all probability acted upon the assumption that a long center, cast hollow, was an essential feature of Stirrat’s invention, as otherwise the subsequent patent to O’Keefe & Filley, No. 358,123, for a water box bolted to the under side of the long center, would not have been granted. But, -whether such was or was not the view entertained by the patent office, the court is of the opinion that such is the correct view. The specification describes the long-center as being “cast with a projection having a water passage through it,” and there is no suggestion in the specification that the object which the inventor hoped to accomplish in the way of preventing the long center from warping could be accomplished by other equivalent means, as by bolting a water pipe thereto, for the purpose of cooling and supporting it.

In conclusion it is only necessary to say that it is only by limiting the Stirrat patent to the precise form of device shown in the specification that the patent can be sustained as a valid grant in view of the prior state of the art. The long center, cast hollow, simply takes the place of one of the two water pipes which were formerly in use. Whatever advantage there may be in that precise mode of construction must be conceded to the complainants, but their patent cannot be so construed as to cover the idea of bolting a water pipe, or a water box to the long center for the purpose of cooling it and giving it greater durability. The court holds, therefore, that defendants have not infringed complainants’ letters patent, and the bill is accordingly dismissed.  