derstand the principle of its organization and | pot, whereby the air finds more ready access to construction. Q. Please examine letters patent, marked "complainants' exhibit B," and state in what respect, if any, the principles involved in the organization and construction of the stove, marked "complainants' exhibit A," are identical with those involved in the claims 1, 2, 4 and 5 of the patent marked "exhibit B?" A. I have examined said patent and find it infringes the first claim by using a coal supply reservoir in combination with the place where the fuel is burned, with the stove so constructed that the products of combustion do not pass up above the supply reservoir, but down outside of the fire-pot towards the base of the stove, and out through a main draught flue; and that it infringes the third claim by using a fire-pot resting on a base, and imperforated and so constructed and applied in respect to the coal supply reservoir, that an inclosed horizontal chamber, for the free expansion and circulation of the flame and gases, is formed all around and above the upper edge of the fire-pot; and it infringes the fourth claim by using a descending passage in combination with the continuous flame expansion and circulating passage, and a main draught flue leading out of the base or lower part of the stove; and it infringes the fifth claim by constructing a fire-pot with an imperforated circumference and in form of a trumpet mouth at its upper portion in combination with descending flame passages to the base; and it infringes the second claim by contracting the discharge end of the coal supply reservoir, and expanding the fire-pot and extending the flame passage downward for united operation in a base burning coal supply reservoir stove. Q. Please examine "complainants' exhibit C," and particularly the first and second claims, and state in what respect, if any, they are infringed by defendant's stove, "exhibit A?" A. I have examined said patent, and find it infringes the first claim by using in combination, illumination opening flame expansion chamber, coal supply reservoir, fire-pot, descending flue and draught flue, substantially in the manner as claimed in said patent; and that it infringes the second claim by using in combination a flame expansion chamber formed at the base of the coal supply reservoir and around the upper edge of the fire-pot, and a branch draught flue with damper located substantially in their combination with coal supply reservoir, as claimed in said patent. The case further appears in the opinion. Messrs. E. J. Bennett, B. F. Butler and E. F. Bullard, for appellants: It is not denied, but admitted, that defendants' stove produces substantially the same results that are produced by complainants' and by the use of substantially the same means, by a reservoir stove having a downward draught into the base, forcing the products of combustion down instead of up and around the reservoir and mica lights. The means employed to produce this are the same in each. 1. A contracted reservoir and flaring fire-pot, together forming an extended combustion chamber directly over the incandescent fuel where the gases are burned. 2. The formation of a conical pile of coal by means of this construction of reservoir and fire the gases through the unequal depth of coal from the center of the pile to its outer edge. 3. A downward draught. 4. Mica lights producing illumination, and a damper. The construction of these several parts may differ in form and dimensions, while their functional operation remains the same. In defendants' stove, the reservoir differs slightly in form from complainants', yet it retains the functional form at the lower end, which co-operates with the flaring top of the fire-pot, to form the enlarged combustion chamber directly over the fuel. Therefore, the firepot and reservoir co-operate alike in both, producing the same results, and none other. The same with the revertible draught and mica lights in each. And these results are in no way affected, either by the ring represented in drawing attached to patent, or the absence of such ring, as represented by defendants' stove, as the ring does not produce the combustion chamber, but on the contrary, that chamber is produced by the co-operation of reservoir and fire-pot; and it is not shown that any results are produced by the ring, not produced without it. The combustion chamber cannot, with or without the ring at the base of the reservoir, be enlarged or diminished beyond what is produced by the cooperation of reservoir and fire-pot, as the downward draught passes the products of combustion not up, but down over the fire-pot into the base. Again, defendant's fire-pot is without the flues attached, as shown in complainants' patent, whereby the products of combustion find a passageway into the base. In defendant's stove the passage way is formed by the outer surface of the fire-pot and the inner surface of the casing of the stove. Is this construction any less a passage way? Are there any new or better results produced by this change of form? Are not the functional operations of both passage ways the same? Are they not identical in their principles of operation, bearing the same relation to the other parts of the stove, i. e., serving as channel ways to conduct the products of combustion into the base, and totally inactive agents for any other purpose? When in two devices the end to be accomplished is the same, and the means employed the same, the two devices are, necessarily, the same. Gray v. James, Pet. (C. C.), 394, Justice Washington. If the invention of the patentee be a machine, it will be infringed by a machine which incorporates in its structure and operation the substance of the invention, that is, by an arrangement of mechanism which performs the service, or produces the same effect in the same way, or substantially the same way. Wyeth v. Stone, 1 Story, 273. One machine is the same in substance as another, if the principle be the same, although the form of the machines be different. Bovel v. Moore, Day, 361. When the same general plan is applied for the same purpose, although the mode of construction may be varied, it will still be substantially, in the eye of the patent law, the same. McCormick v. Seymour, 3 Blatchf., 209, Justice Nelson; Blanchard v. Beers, 2 Blatchf., 418; devices into juxtaposition, and there allowing each to work out its own effect without the pro Howe v. Morton, 1 Fish., 586, and Howe v. Williams, 2 Fish., 395, M. S., Justice Sprague. If a person adopt a different mode of carry-duction of something novel, is not invention. No ing the same principle into operation, and the principle admits of a variety of forms, there is an identity of principle, though not an identity of mode. Page v. Ferry, 1 Fish., 310; Hoffman v. Arenson, 8 Blatchf., 324 (paper collars); Curt. Pat., secs. 32, 49. Mr. C. M. Keller, for appellees. Mr. Justice Strong delivered the opinion of the court: The bill of the complainants is founded upon two patents for alleged improvements in baseburning stoves. Of these patents, one is a reissue, dated February 3, 1863, and the other is an original, dated August 11, of the same year. The earliest asserts twelve claims, of which the first five only are charged to have been infringed by the defendants and the second contains six claims, upon the first and second of which alone it is averred there has been any encroachment. The answer of the defendants denies both the novelty and the patentability of the inventions claimed, and it denies also the infringement charged in the bill. The stove containing the improvements described in the patent held by the complainants, and that manufactured and sold by the defendants, belong alike to a class of stoves long known as base-burners, or self-feeders, called such because they have a magazine or reservoir suspended above the fire-pot, which may be filled with coal at its upper extremity, and which, when filled, is closed by a cover. The lower end of the reservoir or feeder is left open, and as the coal in the fire-pot is consumed, that in the reservoir falls and supplies the place of that consumed; the combustion being only in the firepot and not in the reservoir. Stoves had been made and they were well known years before either of the complainants' patents were granted, and it is not claimed that merely as base-burning stoves they are within the monopoly of the patents. The inventions claimed are alleged improvements in the structure and arrangement of such stoves. They consist in what is described as a new combination of old and known devices producing a new manufacture, namely: a stove uniting in itself all the advantages of a reservoir stove, and those of 368*] a revertible draft *stove which prevents the products of the combustion in the fire-pot from passing up, around and over the reservoir, thereby heating the fuel therein so as to expel its gases, and cause their explosion as well as their escape into the apartments where the stove may be placed. All the devices of which the alleged combination is made are confessedly old. No claim is made for any one of them singly, as an independent invention. It must be conceded that a new combination, if it produces new and useful results, is patentable, though all the constituents of the combination were well known and in common use before the combination was made. But the results must be a product of the combination, and not a mere aggregate of several results, each the complete product of one of the combined elements. Combined results are not necessarily a novel result, nor are they an old result obtained in a new and improved manner. Merely bringing old one by bringing together several old devicses without producing a new and useful result, the joint product of the elements of the combination and something more than an aggregate of old results, can acquire a right to prevent others from using the same devices, either singly or in other combinations, or, even if a new and useful result is obtained, can prevent others from using some of the devices, omitting others, in com bination. If, now, we examine the patents held by the complainants, looking first at the objects sought to be obtained by the combinations for which the patents were granted, they are, as described in the specification, first, to prevent the passage of the products of combustion up, around, and over the top of the coal supply reservoir, so as to heat a surrounding jacket thereof; and, second, to heat a circulating or ascending body of air by means of radiated heat from the fire-pot and at the same time to heat the base of the stove by means of direct heat circulating through descending flues which lead into the ash pit, or around it, and to the smoke *and [*369 draft flue. A third avowed object is to secure economy by retarding the fall of the coal into the fire-pot from the supply reservoir, and by causing the flame to circulate outside of the contracted discharge of the reservoir, and around the upper edge of the fire-pot, and thence to descend around or under the base of the stove in its passage to the smoke and draft flue. Such are the avowed objects of the combinations claimed to have been devised by the patentees, and their effects they assert to be, husbanding the radiated heat and using it for the purpose of warming the upper part of the stove and the room in which it is situated, as well as for heating air for warming rooms above, if desirable, and at the same time so confining the direct fire heat, and keeping it in contact with the base portion of the stove as to insure warming it to a comfortable degree. A second effect claimed is relief of the incandescent coal from the weight of the body of superincumbent coal, thus preventing the compression of the burning coal in the fire-pot, and securing for the flame free expansion, thus enabling it to act with greater heating effect upon the lower portion of the stove in its passage to the smoke and draft flue. The combination employed to produce these effects consists of the following devices, among others: 1. A flaring fire-pot supported by a base, the diameter of the pot being larger at the top than at the bottom. 2. A magazine or reservoir for supplying coal located over the fire-pot, and having its lower end contracted. 3. Revertible passages or flues outside of the pot for the conduct of the products of combustion downwards to the base of the stove and thence to a main draft flue leading thereout. 4. A direct draft for such stoves as are constructed with revertible flues, the direct draft being obtained by a flue passing out above the fire-pot and provided with a damper to be closed after the fuel has been ignited. 5. Openings in the case or exterior of the stove and the insertion of mica therein £4, 370*] purpose of illuminating the room in which the stove may be with the light of the burning fuel. These devices with others are brought to gether and claimed as a new combination, and several combinations of some of them are also claimed as inventions, producing novel and useful results. What those other devices are we need not specify, for it is not shown that they are employed by the defendants. separated from the firepot. The whole space around the magazine and the fire-pot is completely inclosed. There is but a single chamber round the reservoir, over the surface of the burning coal, and around the fire-pot. Through this chamber the products of combustion pass, either through the direct draft-flue, when that is in use, or to the base of the stove and thence outwards. This arrangement also excludes the possibility of an effect claimed for the Hailes and Treadwell invention. It admits of no space around the fire-pot to which the external air can have access. The stove of the defendants does, however, contain all those mentioned and contain them in combination. That each of them was an old device, well known and in public use before the It is not, then, the combination of old devices patents of the complainants were granted, is which the defendants use, that Hailes and abundantly proved by the evidence submitted. Treadwell invented. It is not those old devices A flaring fire-pot, a supply reservoir with its that produce the new results claimed. The comlower extremity of smaller diameter than its plainants' combination is a different thing. It upper, revertible flues, a place for flame expan-has a greater number of constituent elements. sion above the fire-pot, the addition of a direct It consists in the employment of the devices draft for use in igniting the fuel, provided with used by the defendants, together with others a damper, and the insertion of mica for illumi- they do not use, and the result of the entire comnation openings, were all found in stoves be- bination is the production of a stove differing fore Hailes and Treadwell claimed to have made very materially from that of the de- [*372 their invention. It is true there is a peculiarity fendants. And the defendants' combination in the construction of the lower extremity of cannot produce the results claimed for that of the complainant's supply reservoir. It is pro- the complainants. We have said that the new vided with a circular flange, extending outward results claimed, whatever they may be, are not and bending downward, so as to fit upon the the production of the combined devices common upper rim of the fire-pot, and thus form a to both stoves. The devices used by the defendclosed combustion chamber. This, of course, ants produce no new effects, because used in cuts off communication with the space around combination. The space around the fire-pot leadthe upper part of the reservoir, and confines the ing to the base doubtless secures the beneficial flame and other products of combustion within results long known to follow the use of reverta circular combustion chamber thus formed, ible flues. It may be conceded to be an equivaleaving no outlet for them except through ear lent for such flues. But the results of its conpassages into revertible flues. For this device, struction are not changed by the fact that a flarthe peculiar structure of the reservoir, and the ing fire-pot, and a supply reservoir with a conformation of the closed expansion chamber, tracted discharge end, and openings for illumithere is no equivalent in the defendant's stove. nation are used in the same stove. It still operThere is no such closed chamber. The reservoir ates to conduct the products of combustion to does not rest on the fire-pot. It has no connec- the base, and into the exit flue. No new operation with it or with the sides of the stove. Nortion is given to it by the combination. The same may be said of every other device employed by the defendants which is also in the complainant's combination. Each produces its appropriate effect unchanged by the others. That effect has no relation to the combination; in no sense can it be called its product. Thus far nothing novel is produced. This, then, is mere aggregation of devices, not invention and, consequently, the use of those devices, either singly or together, cannot be held to be any infringement of rights belonging to the complainants. is there any obstacle interposed to the passage of the products of combustion up and around the reservoir when the flue for direct draft is open. And when that flue is closed, the flame is not detained over the burning coal, but the 371*] products of *combustion pass directly across the edge of the fire-pot and descend along the sides thereof to the inferior draft passage. Such an arrangement is not fitted to produce the effects sought and claimed for the complainants' stoves. On the contrary, it plainly ex cludes them. There are other differences in the devices used both in the complainants' and the defendants' stoves, which we think are substantial, and not merely formal. The combination claimed by the complainants passes the products of combustion out of the chamber through perforations in the flange or through ears into flues leading downwards but wholly exterior to the fire-pot, and not in contact with it. This arrangement makes it possible to introduce external air through perforations in the outer casing of the stove, and allow it when heated by contact with the fire-pot and the descending flues to escape from the top. Accordingly the outer casing is perforated, and there is no closed magazine around the fire-pot. But in the defendants' stove there is no such device and no such effects are produced. There are no external downward flues We pass now to consider more in detail the claims in the complainants' patents which it is alleged the defendants have infringed. The first in the re-issued patent, dated February 3, 1863, is unquestionably too broad to be sustained, unless limited to the means described in the specification. So it was doubtless intended by the patentees to be limited, for the claim speaks of the combination claimed "as substantially described," that is, described in the specification. Thus limited, one of its essential elements is a closed combustion-chamber over the fire-pot, formed by a flange of the reservoir resting on the upper edge of the pot, and provided with perforations or ears connecting with two flues passing downwards. This element is indispensable for the purposes asserted in the claim, [*373 as well as in the specification. And the peculiar structure of the chamber is more than formal. It is functional. It prevents the passage of the flame and other products of combustion up, around and over the supply reservoir, which is a leading avowed object of the invention, precisely the improvement patented. But this constituent of the combination the defendants have never used, nor have they used any corresponding device, or device producing the same results. cribed. In the main this is the same combination as that claimed in the re-issued patent we have had under consideration. The only change is the addition of illumination openings. These were a well known device applied to stoves long before either of the patents were granted. They perform no peculiar office in the new combination. They have no possible relation to it. They do not affect, in the slightest degree, the be. It is impossible to regard the mere condition of such openings to a stove containing the improvements described in the re-issued patent, as the formation of a new patentable combination. It is not invention. If, however, it were, the defendants have not trespassed upon it, for of the combination the peculiarly formed close expansion-chamber is an essential constituent, and that is not found in the defendants' stove. *Similar remarks might be made re- [*375 specting the second claim of the patent of August, the only remaining one alleged to have been infringed. All the elements of the combination have not been used by the defendants. The decree of the Circuit Court is affirmed. The second claim is for contracting the discharge end of the coal-supply reservoir, expand-results of that combination, whatever they may ing the fire-pot, and extending the flame passage downward for united operation in a base-burning coal supply reservoir stove or furnace, essentially as set forth. The means set forth for extending the flame passage downwards are perforations through the flange forming the lateral boundary of the closed combustion-chamber, or ears leading thereout and close flues extending from the ears or perforations downward at some distance from the fire-pot through a space bounded on one side by the fire-pot and on the other by an outer casing of the stove perforated for the admission of external air. It might, perhaps, be questioned whether there is any device in the defendants' stove corresponding to this, but waiving the consideration of that question, it is very evident that the combination of the three devices named is not the work of invention. They have no relation to each other. Neither the form of the feeder, nor the shape of the fire-pot bears at all upon the direction of the draft passages. There is no novel result flowing from the joint operation of the three devices. The revertible flues have no more to do with a stove supplied by a feeder than they would have with a stove supplied by hand. There is, therefore, nothing in this claim that interferes with what the defendants have done. An essential element of the combinations mentioned in both the third and fourth claims, is the closed combustion-chamber, formed in part by a circular flange extending outward and clos- | ing on the top of the fire-pot, with perforations in it, or ears for connection with the downward 374*] flues, or it is *those perforations or ears leading out of such a chamber to the descending passages. These devices the defendants do not employ, and they cannot be used in the defendants' stove. There has been, therefore, no infringment of these claims. The fifth claim is the only remaining one contained in the re-issue which the defendants are alleged to have invaded. It is constructing the fire-pot of a base-burning stove with an imperforated circumference and in the form of a trumpet mouth at its upper extremity, in combination with descending flame passages, substantially as described, and for the purposes set forth. How in combination? As described in the specification, united by means of perforated flanges or ears of the pot, involving, of course, the presence of a closed combustion-chamber constructed substantially as already described. Construing the claim thus, as we think it must be construed, the defendants have been guilty of no infringement. Passing now to the second patent, issued August 11, 1863, we observe that its first claim was for a combination of the illumination openings, flame expansion-chamber, coal supply reservoir, fire-pot, descending flue and draft flue, substantially in the manner and for the purpose de *THE MERCHANTS' MUTUAL IN- [*159 SURANCE COMPANY, Piff. in Err., v. THOMAS BARING et al., as Baring Brothers & Company. (See S. C., 20 Wall., 159-165.) Instructions to jury, error in—lien on vessel for advances-insurable interest. of fact assumed in a prayer for instruction to a 1. If there be no evidence to support the theory jury, the court should reject it, as it is error to leave a question to a jury in respect to which there is no evidence. 2. Advances made to equip the vessel and to procure a cargo for her in the described voyage, are presumed to have been made on the credit of the vessel, where the record fails to disclose any fact or circumstance to overcome that presumption. 3. Such advances constitute a lien upon the ship, and such a lien gives the lender an insurable interest in the ship. [No. 224.] Argued Mar. 6, 1874. Decided Mar. 23, 1874. IN Messrs. Wm. M. Evarts and J. H. Ashton, for plaintiff in error. Messrs. J. A. Campbell, Duncan G. Campbell and P. Phillips, for defendants in er ror. Mr. Justice Clifford delivered the opinion of the court: Advances were made by the plaintiffs, as alleged in the declaration, to the master and owners of the bark, for the purposes of her equipment, and to procure a cargo for the vessel in a voyage from Cadiz in Spain, to the Port of New Orleans; and the plaintiffs also allege that they, through their agents, obtained a policy of insurance, dated December 6, 1867, and executed by the Corporation defendants, insuring the hull of the bark in the sum of $9,000, in the name of their agents, containing the clauses, "on account of whom it may concern," and "lost or not lost," for the protection of those advances. They also allege that the bark, though well officered, manned and equipped, suffered so much on the voyage, from the violence of the wind and the force of the sea, that the master, with a view to the safety of the officers and crew, and for the preservation of the cargo, found it necessary to put into the Port of St. Jago de Cuba, for such repairs as would enable him to prosecute the voyage; that their agents gave due notice of those facts to the President of the Insurance Company; that the Secretary of the Company subsequently informed the agents of the plaintiffs, that the Insurance Company had decided to send an agent to the port of refuge to take charge of the interests of all concerned, and the plaintiffs aver that from the moment the agent of the Insurance Company arrived there, he took exclusive charge of the repairs of the vessel, and caused such work to be performed as he, the agent, thought to be necessary, and that he obtained from their agent there the funds necessary to pay for all such repairs. All necessary repairs were made, and the bark completed her voyage; and the further allega160*] tion is, that after her arrival *at the port of destination, an adjustment of averages was made by the adjusters of averages in that port for costs, charges and damages in making such repairs, and that in the said adjustment they, the plaintiffs, were awarded the sum of $3,507, on the said policy of insurance. Demand of payment having been made, and payment having been refused, the plaintiff's commenced the present suit. Service was made and the defendants appeared and filed an answer, which is equivalent to the general issue in an action of assumpsit, and a special plea that the bark, at the time of her departure and throughout both the outward and return voyages was unseaworthy, contrary to the stipulations of the policy, and in violation of its express and implied warranty. Subsequently, the parties went to trial, and the verdict and judgment were for the plaintiff for the amount awarded by the average adjusters. Exceptions were taken by the defendants to the rulings of the court in refusing to instruct the jury as they requested. giving any statement whatever of the evidence which was submitted to the jury. Evidence to show that the action was founded upon a bottomry bond, or that such a bond was offered in evidence or introduced at the trial, is entirely wanting; nor is there the slightest *evidence, direct or circumstan- [*161 tial, to show that any such question as that involved in the third prayer for instruction did or could have arisen in the case, or that the instruction was a proper one, in any view of the controversy, for the consideration of the jury. Viewed in the light of these suggestions, as the case should be, it is clear that the several rulings of the court, in refusing to give the three prayers for instruction, may be considered together, as they involve but one question in an appellate court. Correct instructions, if applicable to the case, the court, as a general rule, is required to give, unless the same are in substance and effect embodied in those previously given by the court to the jury; but the court is never required by law to give an instruction to the jury which is not applicable to the case, even though it be correct as an abstract principle or rule of law; and it may be added that no prayer for instruction, whether presented by the plaintiff or the defendant, can be regarded as applicable to the case when it is wholly unsupported by the evidence introduced to the jury. Competent evidence may be written or oral, direct or circumstantial, but when there is no legal evidence of any kind to support the uneory of fact embodied in a prayer for instruction, whether presented by the plaintiff or the defendant, the instruction should always be refused; and such a ruling can never become a good cause for reversing the judgment. It is clearly error in a court, said Taney, Ch. J., to charge a jury upon a supposed or conjectural state of facts, of which no evidence has been offered, as the instruction presupposes that there is some evidence before the jury which they may think sufficient to establish the fact hypothetically assumed in that way by the court, and if there is no evidence which they have a right to consider, then the *charge [*162 does not aid them in coming to a correct conThree prayers for instructions were presented clusion, but its tendency is to embarrass and misby the defendants, all of which were refused: lead them, as it may induce them to indulge in (1) That if the evidence shows that the insur- conjectures instead of weighing the testimony. able interest of the plaintiffs was a bottomry U. S. v. Breitling, 20 How., 254, 15 L. ed., 902. bond on the bark, and that the vessel arrived When a prayer for instruction is presented to in safety at the port of destination, the jury the court, and there is no evidence upon the subshould find for the defendants. (2) That it is ject, in the case for the consideration of the only when the vessel insured is lost, that the as-jury, it ought always to be withheld; and if it sured on a bottomry bond can recover, and that if the proof is that there was no loss or destruction of the bark, the jury should find for the dedants, if the plaintiffs had insured on a bottomry bond. (3) That the defendants were not bound to tender back the premiums of insurance before availing themselves of any defense against the validity of the policy of insurance, or for its avoidance by a subsequent clause. Nothing appears in the record except the declaration, the answer, the verdict and judgment, the three bills of exceptions to the rulings of the court, in refusing to instruct the jury as requested, neither of which contains any report of the evidence, and the motion for a new trial, which merely states that the verdict of the jury is contrary to law and the evidence, without is given under such circumstances, it will, as a general rule, be regarded as error in the court, for the reason that its tendency may be, and often is, to mislead the jury by withdrawing their attention from the legitimate points of inquiry involved in the issue. Goodman v. Simonds, 20 How., 359, 15 L. ed. 938. Bills of exceptions ought to state that evidence was offered of the facts upon which the opinion of the court is prayed, else the court is under no obligation to give the instruction. Vasse v. Smith, 6 Cranch, 226; U. S. v. Dunham, 21 Law Rep., 591; Caldwell v. U. S., 8 How. 366; Blackburn v. Crawford, 3 Wall., 176, 18 L. ed. 186. Though the judge may refuse to declare the law to the jury on a hypothetical question, yet if he gives the instruction and it is erroneous, it is the |