Reporter's Statement of the Case is entitled to compensation and the amount of compensation, if any, for the use of said inventions the court shall take into consideration, if and so far as the facts may warrant, the facts, if proved, that while said David. McD. Shearer was engaged in perfecting the invention he was in the service of the United States as a junior engineer superintendent in charge of willow bank revetment construction under the Mississippi River Commission, and whether and, if at all, to what extent said. inventions or any of them were discovered or developed during the working hours of his Government service, and to what extent his said inventions for protection of river channels and banks differ from the methods previously used, in material, method of laying, permanency, and value, and, whether if at all to what extent the expense of making experiments, trials, and tests for the purpose of perfecting said inventions was paid by the United States, and if any such expense was incurred by the United States, whether and, if at all, to what extent the United States received compensation for such expense. Either party may appeal to the Supreme Court of the United States upon any such question where appeals now lie in other cases, arising during the progress of the hearing of said claim, and from any judgment in said case, at any time within ninety days after the rendition thereof; and any judgment rendered in favor of the claimant shall be paid in the same manner as other judgments of said Court of Claims. Approved, December 17, 1930. A copy of said act is in evidence as plaintiff's exhibit 1. Plaintiff is the party named in the act, is the sole owner of the patents in suit, and has never voluntarily licensed the defendant under any of the patents in suit. 3. The question of the amount of recovery, if any, is reserved until after determination by this Court of the question of liability. 4. The patents relate generally to structures intended to cover and protect the banks of rivers against erosion by the water. Such structures are termed revetments, and are customarily sunk in the river over the subaqueous banks and extend some distance out into the river and also up and down the bank in the direction of flow, over the section of the bank it is desired to protect. Reporter's Statement of the Case Patent No. 1173879 5. Patent No. 1173879 relates to revetment structure, and Fig. 6 thereof reproduced below is a plan view of the patented revetment structure, showing one complete section and the side and end portion of adjacent sections. The patent discloses a revetment mat formed of a multiplicity of concrete slabs F, the length of each slab being much greater than its width, a number of such spaced apart slabs being Reporter's Statement of the Case flexibly joined together in a section D, with their longer dimensions adjacent, by being cast over a fabric or mesh of reinforcing wires G. The outside or "border" strands H and H' attached to the reinforcing fabric are not embedded in the concrete, but are left exposed on opposite sides of the sections. In placing the revetment in position, a number of such sections D, D1, and D2 are joined side by side, with the shorter sides of the slabs adjacent, but spaced apart, thus forming continuous longitudinal spaced channels between the sections. Extending through these channels are placed strong cables E termed "launching cables" or "launching strands", and the border strands and launching cables are fastened together at intervals by bolted clips or "Curry ties." The adjacent ends of the border strands may be lapped and the individual slabs may have their edges beveled to facilitate flexure of the assembled mat. The structure thus described may be assembled upon a barge and passed over the side over sheaves or rollers, additional sections being attached as the mat is paid out over the launching ways, and the launching barge being moved along as the mat is paid out, the launching cables being capable "of supporting the entire mat in the course of launching in order to relieve the concrete units and the mat sections themselves from breaking strain." The patent states that such a mat "is not only economical of itself but capable of being economically laid and is highly practical for the purposes for which it is intended either in strong currents or great depths. * * is, furthermore, particularly adapted for subaqueous application." Patent No. 1173880 6. Patent No. 1173880 relates to a molding frame for casting the revetment mat of patent No. 1173879 and Figs. 1 and 3 thereof, reproduced herewith, are respectively a fragmentary top plan view of the patented mold, and a fragmentary transverse section thereof on an enlarged scale. Reporter's Statement of the Case The patent discloses apparatus in which a complete section of the revetment mat may be cast at one time. The mold is formed of a pair of longitudinal members 10, which form the end surfaces of the slabs forming the section, and a plurality of transverse members 12, which form the long sides of the individual slabs, the transverse members being notched on their inner sides as at 11 to receive the ends of the transverse members 12, and both the longitudinal and transverse members being notched on their lower sides at the Reporter's Statement of the Case desired intervals to permit the reinforcing wire fabric or mesh to be held in position to be embedded in the concrete. The inner faces of the transverse members 10 are beveled downwardly and outwardly to facilitate removal of the form after the concrete has set. Upon each of the transverse members 12 there is slidably mounted an L-shaped support 21 for the reinforcing wires. Arranged at intervals and longitudinally of the lower edge of each of the supports 21 are depending fingers or legs 23 which form stirrups for holding the reinforcing wires 15. The supports 21 are shorter than the transverse members 12 on which they slide so that, after the concrete has been poured, they may be slid along the transverse members to disengage the fingers from reinforcing wires and may then be lifted from the mold frame. After the concrete has set, the mold is lifted from it. Patent No. 1229152 7. Patent No. 1229152 relates to apparatus for launching the revetment mat of patent No. 1173879, and Figs. 1, 2, and 3 thereof reproduced herewith, show respectively the arrangement of mooring barges, launching barge, and material barge; Fig. 2, a top plan view of the launching barge; and, Fig. 3, a transverse section thereof. The patent discloses the combination of mooring barges 10, launching barge 11, and material barge 22, so arranged that the launching and material barges may be moved outwardly into the stream under control of the operator while the revetment mat is being paid out or launched over the shore side of the launching barge. The construction of the launching barge disclosed includes a multiplicity of downwardly inclined ways 27 extending athwartship, parallel to each other and provided with rollers 28 upon which the slabs of the revetment mat ride during launching. The launching ways pass over the side of the barge to the discharge end in a smooth curve or arcuate portion. In the curved portion of the ways there is mounted a succession of sheaves 29 between each of the ways 27, these |