Opinion of the Court. to the manner in which the two centre rails were combined to make the angular point or V shape. In our opinion, the construction placed upon this claim by the Circuit Court is right, and is required by the language of the specifications and claim. The claim does not on its face profess to cover a mere mode of connecting, by means of U-shaped channel irons, the intermediate with the external rails. It is in form a claim for a combination of parts, which together constitute a frog of peculiar construction. The elements of that combination, as stated in the claim, are, first, the two centre rails BB' joined to form the V-shaped point; second, the outside diverging or wing rails; third, the channel irons of a U shape uniting the centre rails together, and also to the outside or wing rails, so that the whole shall constitute a frog with the characteristics imparted by the features of this combination. This coincides with the statement contained in the brief of counsel for the appellant, who say, speaking of the invention as described in the second claim: "The elements constituting the invention in controversy are: First, two outside diverging wing and main rails; two inside V-shaped point rails, the four rails being united and joined together by two channel irons bolted to these rails by three lines of rivets or bolts, to wit: one line of bolts, bolting one channel iron to one wing rail; another line of bolts, bolting another channel iron to the other outside wing rail; and the third line of bolts passing through the two inside wings of the two channel plates, and through the webs of the point rails, thereby making one structure or machine. In this construction the cut-away rail forming the point is reinforced on each side by the vertical wings of the channel irons. The claim is for this frog or machine so constructed, a frog composed substantially of the elements above named." The claim refers specifically to the "two centre rails BB' joined to form the V-shaped point." This points explicitly to the drawings, on which the two centre rails are designated by the letters, and also to the mode in which they are shown by the drawings and the description in the specification to be joined, and excludes the idea of constructing a frog, such as is Opinion of the Court. intended to be covered by the second claim, of any other centre rails than those thus pointed out and described. The patentee by this mode of description and of claim has made the centre rails, formed and connected in the manner described to make up the V-shaped point, an essential part of the invention intended to be secured by the second claim. An argument against this construction, made by the counsel for the appellant, is based upon the language of the third claim. That claim is for the channel pieces D extending and bolted or riveted together beyond the point of the frog and connecting rivets C, which extend entirely through the two point rails and the channel pieces, "in combination with the point rails BB', fitted to each other as described." It is admitted that the language of that claim limits it to the point rails formed and connected together so as to make the V-shaped point, according to the specific manner described in the specification and shown in the drawings, and that it does not cover centre rails of any other description. This limitation is based upon the words "fitted to each other as described." It is argued that as this phrase is omitted from the second claim, the contrary inference must prevail, so that that claim may be permitted to extend so as to embrace all centre rails joined to form the V-shaped point, however they may be fitted to each other. But this variation of language does not seem to us so significant. The second claim, by the use of the phrase at its close, "substantially as shown," limits its application quite as effectually to the particular kind of centre rails described in the specification and covered by the first claim; and the reference therein to "the two centre rails B B' joined to form the V-shaped point," can only mean such point rails as are shown in the drawings marked B B', and joined to form the V-shaped point referred to in the drawings and described in the specification "substantially as shown.” If this construction of the second claim needed corroboration, that would be found in the state of the art at the time of the alleged invention, as shown by the proof in the present case. The frogs exhibited in evidence as infringements of the complainant's patent were manufactured by the defendants, as Opinion of the Court. they claimed, under patent No. 148,264, dated March 3, 1874, issued to George Thomas and William Miller, under whom they claim, and also under patent No. 173,804, dated February 22, 1876, issued to Morden, one of the defendants, as inventor. Morden's patent of February 22, 1876, showed a connection of the wing rails for use as frogs by means of a U-iron or “trough plate," the upturned sides of which "are made to conform to the curve of the side rails, as well as to the form of the neck and base of the rails, and are firmly secured to the neck of the rails by bolts or rivets." Instead of holding the V-shaped point in place by the use of channel irons, he provided a Vshaped recess in the channel or trough plate into which the point of the frog was inserted and held; but in applying his device to railroad crossings instead of switches, he used channel or U-shaped irons to connect the points and wing rails. It is true, as suggested by counsel for the appellant, that a crossing of railroad tracks is a very different device from a switch, where the latter is used by means of a frog to shift the engine and train from one line of tracks to another; but the use of channel irons is analogous in the two cases, and it would require no more than ordinary mechanical skill to transfer the channel irons used upon a crossing to firmly hold the parts in place, to a similar use in a frog to unite firmly in their respective positions the centre rails with the exterior rails. Independently, however, of this use of channel irons on crossings, we think that the patent to Morden of February 22, 1876, for an improvement in railroad frogs, considered in itself, leaves no room for invention in the application of channel irons in uniting the V-shaped point rails with the exterior rails. In that patent the invention consisted in forming a metallic plate into a U-shaped trough for the purpose of connecting the outer rails, leaving the V-shaped ends of the point rails to be secured by means of a V-shaped recess in the bed of the plate at the wide end of the trough. There seems to be no invention in dividing that trough into two, so as to connect the centre rails on each side, by means of a separate channel iron or U-shaped trough, with the outer rail exterior to them. For these reasons the decree of the Circuit Court is Affirmed. Opinion of the Court. TOMPKINS v. LITTLE ROCK AND FORT SMITH RAILWAY. WILLIAMS v. LITTLE ROCK, MISSISSIPPI RIVER AND TEXAS RAILWAY. APPEALS FROM THE CIRCUIT COURT OF THE UNITED STATES FOR THE EASTERN DISTRICT OF ARKANSAS. Nos. 70, 71. Argued January 17, 18, 1888.- Decided March 19, 1888. The statute of the State of Arkansas of July 21, 1868, to aid in the con struction of railroads, and the statute of that State of April 10, 1869, to provide for payment of interest upon the bonds of the State issued in aid of such construction, created no lien upon the property of a railroad company for whose benefit such state bonds were issued, in favor of the holder of the bonds, which, after a sale under foreclosure of a mortgage upon the property remained a lien upon it in the hands of the purchaser at the foreclosure sale. IN EQUITY. The case is stated in the opinion of the court. Mr. John R. Dos Passos and Mr. John McClure for appellant. Mr. U. M. Rose and Mr. Attorney General were with them on the brief. Mr. C. W. Huntington and Mr. John F. Dillon for appellees. MR. CHIEF JUSTICE WAITE delivered the opinion of the court. These cases may properly be considered together. The material facts are these: The Little Rock and Fort Smith Railroad Company was incorporated by the State of Arkansas, January 22, 1855, to build and operate a railroad in that State from Little Rock, by the way of Van Buren, to Fort Smith. The Mississippi, Ouachita and Red River Railroad Company was also incorporated by the State on the same day, to build and operate a railroad from the Mississippi River near Gaines' Landing, Opinion of the Court. through or near Camden, to some point on the Red River, at or near Fulton, and thence to the boundary line between Arkansas and Texas. The Little Rock, Pine Bluff and New Orleans Railroad Company was organized November 23, 1868, under the general railroad law of Arkansas, passed July 23, 1868, to build and operate another railroad from Little Rock, through or near Pine Bluff and Monticello, to the state line, with a branch from Pine Bluff to Eunice. On the 21st of July, 1868, the General Assembly passed "an act to aid in the construction of railroads." By this act the State, "for the purpose of securing such lines of railroad in this State as the interests of the people may from time to time require," pledged itself "to issue to each railroad company or corporation, which shall become entitled thereto, the bonds of this State, in the sum of one thousand dollars each, payable in thirty years from the date thereof, with coupons thereto attached, for the payment of interest on the same in the city of New York, semi-annually, at the rate of seven per cent per annum, in the sum of fifteen thousand dollars in bonds for each mile of railroad which has not received a land grant from the United States, and ten thousand dollars in bonds for each mile of railroad which has received a land grant from the United States, on account of which such bonds shall be due and issuable, as provided." To get the aid application was required to be made to the Board of Railroad Commissioners for "the loan of state credit herein provided for," and its approval by that board obtained. The bonds were to be under the seal of the State, and attested by the Secretary of State, and they, or the avails thereof, were to be used "solely for the purpose of providing for the ironing, equipping, building, and completing said road.” They were to be issued only as each ten miles or more of the road was prepared for the iron rails. Sections 7 and 8, which are principally relied on as the ground of recovery, are as follows: "SEC. 7. Be it further enacted, That the Legislature shall from time to time impose upon each railroad company, to which bonds shall have been issued, a tax equal to the amount |