
76 U.S. 50 (____)
9 Wall. 50
CHICAGO
v.
SHELDON.
Supreme Court of United States.

*52 Mr. Tuley, for the city, argued &mdash.
*53 Mr. Justice NELSON delivered the opinion of the court.
It is asserted, on the part of the railway company, that by the true construction of their contract, they are exempt from the assessment made upon their property, and the seventh section of the ordinance of the 23d May, 1859, is referred to and relied on in support of this construction. That section prescribes the obligations and duties of the company in respect to the condition and repairs of the streets during the whole period of the running of the contract, and imposes certain burdens upon it as to repairs, from which, to their extent, the city, or adjoining owners of lots, are relieved. It is insisted that this provision was intended, and so understood by both parties, as regulating the whole subject as it respects improvements of the streets occupied by the company, and to fix in the contract the extent of their liability.
The language of it is somewhat peculiar, and it cannot well be denied but that a fair and reasonable interpretation favors this view. It is as follows: "The said company shall, as respects the grading, paving, macadamizing, filling, or planking *54 of the streets, or parts of the streets, upon which they shall construct their said railways, or any of them, keep eight feet in width along the line of said railway on all the streets where one track is constructed, and sixteen feet in width along the line of said railway where two tracks are constructed, in good repair and condition." Now, it is quite clear that the above recitals embrace the whole subject of improvements of the streets, and that it was present to the minds of the parties when entering into the stipulation respecting repairs that followed. And this being so, it is difficult to deny, but that these stipulations were made as fixing the proportion or share of these general improvements which should be imposed on the company, namely, they should keep in good condition and repair eight or sixteen feet, as they used a single or double track, along the entire length of the road. They were not to grade, pave, macadamize, fill, or plank even the above width or distance, except so far as such work came within the category of repairs.
What adds great weight to this view is, it accords with the practical construction given to the contract by both parties. It was entered into, as we have seen, on the 23d May, 1859. Several of these special assessments were authorized subsequently by the common council and collected, but no attempt was made to assess the railroad property of the company. Nor was any question raised as to its exemption till 1866, and not then by the city, but by some of the proprietors of lots fronting on the streets. In cases where the language used by the parties to the contract is indefinite or ambiguous, and, hence, of doubtful construction, the practical interpretation by the parties themselves is entitled to great, if not controlling, influence. The interest of each, generally, leads him to a construction most favorable to himself, and when the difference has become serious, and beyond amicable adjustment, it can be settled only by the arbitrament of the law. But, in an executory contract, and where its execution necessarily involves a practical construction, if the minds of both parties concur, there can be no great danger in the adoption of it by the court as the true one.
*55 There is another consideration in the case entitled to weight in the interpretation of this contract; and that is the language of the contract made between the city and the company in 1864.[*] This ordinance is in pari materia with the one of 1859, and helps to explain any ambiguity in it.
We may add, also, that the learned judge who delivered the opinion of the court, maintaining the liability of this company to the payment of the assessment, does not place his opinion upon the ground that the contract did not exempt it, but that the legislature were disabled by the constitution of the State from conferring any such power on the city. The objection is founded on the clauses of the constitution, which provide that taxes shall be levied so that each person shall pay in proportion to the value of his property; and that where corporate authorities of counties, cities, &c., are authorized to levy and collect taxes for corporate purposes, the taxes shall be uniform in respect to persons and property.
We are not concerned to deal with these provisions, as it is perfectly settled by the decisions of the Supreme Court of the State that, according to the true construction of them, they do not forbid the legislature commuting with individuals or corporate bodies the burdens of general or specific taxes or assessments, of the character of those in question, for what they may deem an equivalent. This has been so frequently decided that we need only refer to the cases.[] It is supposed by the counsel for the city that this doctrine has been modified by the recent cases of Chicago v. Larned, decided in 1864, and The Same v. Baer, in 1866. But, on looking into these cases, we find no references to the cases above cited, or to the doctrine they maintain. If it were otherwise, however, we could not agree that such decisions could have the effect to invalidate the contract in question. A contract having been entered into between the parties, valid at the time, by the laws of the State, it is not competent *56 even for its legislature to pass an act impairing its obligation, much less could any decision of its courts have that effect.
A point is made, that the legislature have not conferred, or intended to confer, authority upon the city to make this contract. We need only say that full power was not only conferred, but that the contract itself has been since ratified by this body.
JUDGMENT AFFIRMED.
NOTES
[*]  See it, supra, p. 52.
[]  Illinois Central Railroad v. County of McLean, 17 Illinois, 291; Hunsaker v. Wright, 30 Id. 146; Neustadt v. Illinois Central Railroad, 31 Id. 484.
