Opinion of the Court.

stove," the original patent, No. 56,686, having been granted to said Bussey, as inventor, July 24th, 1866, and reissued to him, as No. 3,649, September 28th, 1869; (2) letters patent No. 142,933, granted to David H. Nation and Ezekiel C. Little, as inventors, September 16th, 1873, for an "improvement in reservoir cooking-stoves;" (3) letters patent No. 142,934, granted to said Nation and Little, as inventors, September 16th, 1873, for an "improvement in reservoir cooking-stoves." After an answer and proofs, the Circuit Court made a decree finding no infringement of No. 3,815 and dismissing the bill as to that patent; decreeing that the other two patents were valid and had been infringed as to all their claims; and awarding a perpetual injunction as to those claims and an accounting before a master. The master reported one cent damages. The plaintiffs excepted to the report, claiming $14,972 damages. The court confirmed the report and made a decree accordingly, which also provided that the entire costs to be taxed in the suit should be divided and that the plaintiffs should pay of them and the defendant Both parties appealed to this

court.

The specification of No. 3,815 says:

"Figure 1 is a side elevation; Fig. 2, a rear elevation; Fig. 3, a plan; Fig. 4, a vertical section at the line z z; Fig. 5, a front view of a section at the line y y; and Fig. 6, a top view of a partial section at the line xx, all of a cooking-stove embodying my said invention, like parts being marked by the same letters in all the figures, and the arrows therein being indicative of the courses in which the gases of combustion pass through the stove. One part of my invention consists in arranging a culinary boiler or hot-water reservoir in the rear of the oven of a diving-flue cooking stove, with an exit-flue extending down the front, under the bottom and up the rear of the said reservoir, substantially as hereinafter described and specified. It also consists in arranging a culinary boiler or hot-water reservoir in the rear of the oven of a diving-flue cooking-stove, with an exit-flue leading from some point in the rear of the vertical flue or flues below the top of the said oven, and continuing under the bottom and up the rear side of said reservoir, substantially as hereinafter described and specified. It also con

Opinion of the Court.

sists in the arrangement of a diving-flue cooking-stove, with an exit-passage constructed in the vertical rear flue or flues thereof, and below the top of the oven, in such a manner that the gases of combustion, after passing through such exit-passage, will impinge

upon or come in contact with the bottom or sides of a reservoir placed in the rear of the stove, and just above said exit-passage, substantially as hereinafter described and specified. It also consists in the employment of a thin plate or sheet of metal between the front plate of the reservoir and the rear-end vertical flues of

Opinion of the Court.

the said stove, substantially as shown and specified. In illustration of my invention, the aforesaid drawings represent a cookingstove having an oven, A, a culinary boiler or hot-water reservoir, B, arranged opposite to the rear upright side or end d of the oven, and an exit-flue, E E', extended from the central vertical flue K of said stove at a point below the top of the oven, under or across the bottom g of the reservoir, and from thence up along the rear upright side of said boiler or reservoir to the draft-pipe I. For the purpose of allowing the boiler to heat more readily, a portion of the rear-end vertical plate of said stove is removed, so as to uncover the upper portion of the rear-end vertical flues, and the front of the boiler is attached to the rear of said flues, in the manner shown and described in my reissued patent of July 24th, 1866. Between the inner side of the boiler B and the rear-end vertical flues K and L L', a plate may be employed, indicated by dotted line ww. The object of this plate is as follows: It has been as-. certained by experience that when, during the use of the oven for baking purposes, a large quantity of cold water is suddenly poured into the reservoir, and there is nothing between the front of the boiler and gases of combustion passing through the rearend vertical flues, the heat of the said gases will be so much absorbed by the reservoir as to sensibly cool the oven and interfere with the process of baking. To obviate this I employ the thin plate wow, placed between the front of the reservoir and the said rear-end vertical flues, and which, while it allows sufficient heat to pass through it to aid in heating the boiler, protects the front thereof from the direct impact of the gases of combustion, and preserves an equable heat in the oven. In case the said plate is dispensed with the inner side J of the said boiler will form a part of the lateral rear casing of the said rear-end vertical flues, and will be heated by direct contact with the gases of combustion as they pass down and up the same. M is the fire-box, and N and R the top and bottom flues of said stove. The operation of my said invention is as follows: A fire being kindled in the fire-box M, and the damper Q at the top of the oven being open, so as to allow of a direct draft, the gases of combustion from the said firebox will pass down the middle vertical flue K, through the exitpassage F and exit-flue E E', to the smoke-pipe I, heating the contents of the reservoir in its passage through the exit-flue, as afore-. said. By this mode of construction I am enabled to obviate what

Opinion of the Court.

has been heretofore the greatest objection to reservoir-stoves of this class, namely, that the reservoirs would not heat with a direct draft. It will also be observed that, by this device of constructing the exit-passage below the top of the oven, I can at the same time by a direct draft heat the rear side of the oven and the reservoir, instead of wasting the heat by carrying it directly to the chimney. When the damper Q is closed, for the purpose of heating the oven, the gases of combustion will pass down the side vertical flues L L and under the bottom of the oven, returning through a central horizontal flue to the central vertical flue K, from which they pass through the exit-flue E E', aforesaid. I am aware that cooking-stoves have been in use in which the reservoir has been incased or inclosed on all sides except the top by a kind of expanded flue, through which the gases of combustion are made to pass. The advantages of my plan over this device are twofold: First, it is much more economical, requiring far less material and labor to construct it; and, second, by confining the heat and gases of combustion to a small space at the bottom and rear of the reservoir, the contents thereof will be much more effectually heated than where the products of combustion are admitted to an extensive flue-space and permitted to rise and expend their heat at or near the top of the reservoir.”

The claims of the patent, the first 4 only of which are alleged to have been infringed, are as follows:

"1. A diving-flue cooking-stove with the exit flue so constructed as to inclose on the sides and bottom the culinary boiler or hot-water reservoir B. 2. A diving-flue cooking-stove with the exit-flue constructed across the bottom and up the rear upright side of the culinary boiler or hot-water reservoir B. 3. A diving-flue cooking-stove constructed with an exit passage, F, below the top of the oven, and an exit-flue E E, in combination with an uncased reservoir, B, attached to the rear of the stove, and placed just above such exit passage, and so arranged that the gases of combustion, in passing through such exit-flue, will impinge upon or come in direct contact with said reservoir, substantially as and for the purposes hereinbefore specified. 4. An exit-passage, F, constructed in the rear of a diving-flue cooking-stove and below the top of the oven, in combination with

Opinion of the Court.

an uncased reservoir, B, attached to the rear of the stove, the bottom of which reservoir is also below the top of the oven, and so arranged that the gases of combustion will come in contact with and heat such reservoir by, a direct draft from the fire-box to the smoke-pipe. 5. In a cooking-stove wherein the rear-end vertical plate, or a portion of the same, has been removed for the purpose of heating a reservoir placed in the rear thereof, the shieldplate w w, in combination with the uncased reservoir B and the rear-end vertical flues K, L, and L', substantially as and for the purposes herein before described and specified."

The defendant's stove has three flues and an exit-passage below the top of the oven, and a reservoir, the bottom of which is below the top of the oven; but no part of the rear-end vertical plate is removed so as to allow the gases of combustion to come into direct contact with the front of the reservoir, nor is any of such plate employed as the plate w w of the patent, but there is a dead air-space between the rear plate of the flue and the front of the reservoir. The exit-flue is not a narrow one, carried across the middle of the bottom of the reservoir, as in the patent, but the products of combustion, on leaving the flue-space, pass into a chamber beneath the reservoir, the area of which is co-extensive with the entire surface of the bottom of the reservoir; and the vertical passage out of such chamber is not one outside of the rear of the reservoir, but is one in and through the body of the reservoir, and removable with it. In view of the earlier patents put in evidence, we are of opinion that the 4 claims in question must be limited to a structure in which the front of the reservoir has no air-space in front of it, and in which the exit-flue does not expand into a chamber at the bottom of the reservoir, and in which the vertical part of the exit-flue does not pass up through the reservoir. Under this construction there is no infringement of No. 3,815.

Claim 1, in requiring that the exit-flue shall "inclose on the sides and bottom," the reservoir, requires, in the language of the text of the specification, that it shall extend "down the front, under the bottom and up the rear" of the reservoir;