asked to give damages beyond those prescribed. This was always denied; but, so far as we have been able to discover, it has never been decided

that less could not be given, under proper circumstances. "Shall" ought undoubtedly to be construed as meaning "must," for the purpose of sustaining or enforcing an existing right; but it need not be for creating a new one. Neither under the statute nor the Rule has a party the legal right to demand a judgment for damages in excess of interest. All is left to the judicial discretion of the court, and this is true as well as to the amount as to the propriety of giving any at all. This being the case, we think the rule may fairly be construed as limiting the amount beyond which we cannot go, but as leaving us at liberty to give less than the full sum in cases where in our judgment, the circumstances are such as to make it proper to do so. An inflexible rule, requiring us to award a certain specified amount, or none at all, would oftentimes operate to defeat itself. The object is to discourage frivolous appeals, as well as to compensate to some extent for the loss which results from delay. Oftentimes ten per cent. upon the amount of a judgment might far exceed the loss actually sustained; and in such cases we might decline to award damages at all, if we could not give less, because of the wrong that would be inflicted if we did give them. Thus one of the benefits anticipated from the rule would be lost.

Under these circumstances we hold that while, with the Rule in force, we cannot award as damages for delay more than ten per cent. upon the amount of the judgment, we may, in the exercise of our discretion, give less.

The judgment in this case is affirmed, with costs, and five hundred dollars damages for the delay, in addition to interest at the rate allowed by law and the rules of this court.

In No. 165 between the same parties Mr. Chief Justice Waite delivered the opinion of the court as follows:

The judgment in this case is affirmed, with costs and five hundred dollars damages for delay, in addition to interest. No further opinion will be delivered.

[No. 114.] Submitted Nov. 24, 1876. Decided Jan. 29, 1877.

APPEAL from the Circuit Court of the UnitYork.

ed States for the Southern District of New

The bill in this case was filed in the court below by the appellants, to recover for an alleged infringement of a certain patent, and for an injunction. A decree having been entered in favor of the respondents, the complainants appealed to this court.

Mr. Thomas P. Howe, for appellants. Mr. Edwin B. Smith, Asst. Atty-Gen., for appellees.

Mr. Justice Clifford delivered the opinion of the court:

Holders of valid letters patent enjoy, by virtue of the same, the exclusive right and liberty of making and using the invention therein secured, and of vending the same to others to be used, as provided by the Act of Congress; and the rule of law is well settled, that an invention so secured is property in the holder of the patent, and that as such the right of the holder is as much entitled to protection as any other property, during the term for which the franchise or the exclusive right or privilege is granted. Seymour v. Osborne, 11 Wall., 516 [78 U. S., XX., 33]; 16 Stat. at L., 201.

Inventions may be assigned before they are patented: and it appears that Samuel Lewis claims to have been the original and first inventor of the patented improvement; that he, without having applied for a patent, assigned all his right, title and interest in the invention to the first named complainant; that the assignee made due application for a patent, and that the patent was duly granted to him for the term of seventeen years; and that the patentee, before the suit was commenced, assigned one undivided half part of the same to the other complainant, together with the like proportion of the claims and rights of action of any infringement of the patent by the making, use or sale of the patented improvement.

Due evidence of the assignments was exhibited; and the complainants allege that the respondents have infringed the patent, as more fully set forth in the bill of complaint; and they pray for an account and for an injunction.

peared and filed separate answers.

Briefly stated, the defenses set up in the respective answers are as follows: (1) That Samuel Lewis is not the original and first inventor of the patented improvement. (2) That the patented improvement is neither new nor useful, and was not the proper subject for a patent. (3) That they have never infringed the patent by making, using or selling the patented improvement. (4) That the use, if any, they have made of the patented improvement was done under the directions of the United States, and as their agent or officers.

Proofs were taken by both parties; and, the parties having been fully heard, the circuit court entered a final decree in favor of the respondents, dismissing the bill of complaint. Due appeal was immediately taken by the complainants to this court.

Engineers and practical operators have long

Such obstructions, where they exist in rivers or in channels affected by the ebb and flow of the tide, have the effect to contract the water-course and to accelerate the current or flow and, consequently, to increase very much the difficulties of the operator in his endeavors to blast the rocks or to remove the obstruction, except in seasons of low water, or when the tide is down. Difficulties of the kind almost insuperable, it must be admitted, do exist when attempting to remove such obstructions in large running streams or in deep channels affected by the tide, and that the description of the same given by the patentee in the introductory portion of his specification is not very much exaggerated. Different localities are there referred to, where, from the nature of the bottom of the stream or channel, a coffer-dam could not be constructed and where the drilling by hand from the surface would be impracticable, owing to the depth of the water and the strength of the current, as evidence to show that the invention, if successful, will be of great public utility and impor

tance.

Means of a character to remove such obstructions, the specification states, were unknown prior to the patented improvement, and that im portant water thoroughfares, for the want of adequate means to accomplish such an end, are either entirely or partially closed to vessels of large draught, which may, by the use of the pat ented machine, be converted into highways for the largest ships engaged in commerce and navigation.

Suppose the alleged improvement will effect the described results, or will even facilitate to a considerable extent the removal of such obstructions, all, it would seem, must concede its value and utility; and the patentee proceeds to state that the main object of the same is to enable workmen to continue their operations without suspension or impediment from the strength of the current, the ebb or flow of the tide, or the varying depth of the water. All these results the patentee professes to believe can be accomplished by the mechanism described in the specification and illustrated in the annexed drawings; but it is evident, from the language of the specification, that the supposed inventor had never put the apparatus which he describes to any practical use or test. Enough appears to justify the conclusion that he believed in the theory of the improvement; and that he felt much confidence that the described mechanism would work out the described results.

Having set forth the object and aim of the improvement, the patentee then proceeds to describe the apparatus by which they are to be accomplished, as follows: two boats are pre

By the description it also appears that the manner of constructing the telescopic or sectional portion of the apparatus is to prepare a series of plates of galvanized iron, or any other proper material, of suitable thickness, and bend and fasten them into the form shown in the drawings, which is that of an acute parallelogram, one sliding vertically within another, so as to offer the least possible resistance to the tide or current, thereby easing the work of the anchors, and contributing generally to the control of the apparatus.

Each division of the dam is bent inwards at its upper edge, and at its lower edge has a strip fashioned so as to prevent the sections from separating. Every section is likewise provided with four eyes or eyebolts, one at each side and one at each end, which serve as guides to the several sections while operating, the eyebolts on the bottom section being attached permanently to the chains through which the dam is operated, and the bottom section being also provided with four framed wheels or eyebolts through which the side anchor-chains pass, which are to be operated by windlasses, and which extend from the boats, similar to those shown for the operation of the dam above, through the eyebolts on the bottom section, and then outward to the side anchors. Chains extend from the ends of the boats directly to the end directly from the boats to the side anchors, and anchors, the dam being operated by windlasses.

Drills are provided which work in tubes, the lower ends of the tubes being fastened into braces attached to the bottom section of the dam. Tubes of full length, it is stated, are not deemed essential, as a section of sufficient height above the braces on the bottom section of the dam to prevent the drill from being entirely withdrawn from the tube during a stroke, is for some reasons to be preferred, if the tube is properly set with a rocking joint in the lower brace.

Self anchors, so called, are also provided, which are bars of iron formed and moving in sockets, as shown in the drawings, and which by virtue of their length and free play, adapt themselves to the irregularities of the bottom, and take a rigid and steady hold during the process of drilling. Anchors of the kind are connected with the deck, so as to be taken out of the way when desirable, and the telescopic apparatus is suspended from the deck by four links and bolts, and the several chains are drawn through their respective openings and attached to their proper windlasses.

All the appurtenances, including the boats and dam, being complete and the sliding sections closed, the machine is taken to the spot

Intelligent description of the mode of anchoring the machine and putting it in operation is also given in the specification, as follows: (1) An anchor is let go and its cable paid out to its full length, the boat moving till the anchor takes hold and the chain is taut. (2) Then the other anchor is dropped and the two chains taken up, till the floating structure is held steadily by the two anchors. (3) The side anchors are next launched from a lighter or attendant boat. (4) When these anchors are placed, it is suggested that the diver should be sent down to explore the bottom, to see whether any change of position is desirable. (5) Change may be made in any direction by letting out one cable and taking up another, if it appears that the change will give the self anchors a better face for work when the dam is lowered. (6) When the drills have penetrated to the desired depth, they are withdrawn, and the diver goes down and inserts the charges. (7) The apparatus is then removed and the charges fired, when the machine is replaced as before, and the work continued.

Four claims are made in the specification, as follows: (1) The construction and arrangement of a portable and adjustable dam in sliding or telescopic sections, in the manner and for the purposes described. (2) The combination of the self anchors with the dam, in the manner and for the purposes set forth. (3) The combination of the boats, supports or floats with the dam and the arrangement of anchors to hold the boats in position, in the manner and for the purposes described. (4) The combination and arrangement of windlasses, chains and boats with the dam, so that by the construction thereof a series of drills may be operated within and inclosed by the dam, in the manner and for the purposes described in the specification.

Persons seeking redress for the unlawful use of letters patent in which they have an interest are obliged to allege and prove that they, or those under whom they claim, are the original and first inventors, and that the same have been infringed by the party against whom the suit is brought. Both of these allegations must be proved by the party instituting the suit; but the patent, if introduced in evidence by the complainant, affords a prima facie presumption that the supposed inventor is the original and first inventor of the patented improvement. Evidence to overcome that presumption is admissible, provided that notice of such defense is given in the answer, as required by the rules of equity practice. Seymour v. Osborne, [supra]. Notices of the kind were not given in this case, and it follows that the prima facie presumption must prevail.

Infringement is alleged by the complainants, and the burden is upon them to prove the allegation, as it imputes a wrongful act to the respondents. Such an issue cannot be understand ingly determined without first ascertaining the true nature of the invention as embodied in the claims of the patent, when the same are prop erly construed in view of the descriptive portions of the specification.

Of all the claims of the patent, the first is by far the most important, and embraces all that is embodied in the other three. It is the con

Argument to show that the dam is to be suspended from the main deck is unnecessary, as the statement is three times repeated in the specification of the patent: (1) Figure 3 of the drawings, the specification states, shows the manner of suspending the dam from the main deck. (2) It is stated that the deck has an opening in the center equal to the horizontal area of the dam, and that from the deck the telescopic or sectional portion of the apparatus is suspended. (3) That the telescopic apparatus is suspended from the deck by four links and bolts.

Beyond question, these references show that the patentee, when he claims the construction and arrangement of a portable and adjustable dam in sliding or telescopic sections, means a dam suspended from the deck when in use, and intends to be understood that such suspension of the dam, in the manner and by the means shown, is a necessary element of the claim.

Evidently the sections are not only free to slide in the manner described, but when the dam is in use the sections are to adjust themselves to varying depths of water, such as are caused by the ebb and flow of the tide, which has the effect to vary the distance the dam is suspended from the bottom, showing that the top section must at all times be connected with the boat by links and boits, as stated in the specification, or by equivalent means, and that the bottom section must be permanently connected or attached by chains or equivalent means, with a hoisting apparatus arranged on the boat.

Unless the top section is connected with the boat, the letting down of the bottom section will cause all the other sections to go down with it, and they will not be opened out telescopically, as described by the patentee. On the other hand, if the top section is connected with the boat, and the bottom section is not connected with the hoisting apparatus on the boat, the dam cannot be lifted, and the bottom section will always rest where the machine is placed; or, if the water is deep enough, all the sections will remain extended to their full length, showing that no dam constructed and arranged in the manner described in the descriptive portion of the specification can be within the first claim of the patent, unless the sections are free, at all times when the dam is in operation, to slide on each other, nor unless the top section is attached to or suspended from the boat, nor unless the bottom section is connected with a hoisting apparatus on the boat.

2. Self anchors combined with the dam constitute the second claim, which is merely a subdivision of what is embodied in the first claim. Viewed in that light, it will not be necessary to enter into any extended explanation as to its scope and signification.

Remarks already made show that the dam with telescopic sections was to be self-adjusting to tidal and other variations in the depth of the water where the machine is to be operated, and it is equally clear that the self anchors must be free to slide in their sockets with the rise and fall of the bottom section, in order that they may