"This is a writ of error to the supreme court of the state of North Carolina, and brings up the question whether the recent legislation of the state, concerning the collection of taxes, is, as it affects the plaintiff in error, in violation of that provision of the constitution of the United States which declares that no state shall pass any law impairing the obligation of contracts. As early as 1833, the general assembly of North Carolina incorporated the Wilmington & Weldon railroad company, for the purpose of constructing a railroad in the state, and inserted a provision in the charter 'that the property of said company, and the shares therein, shall be exempted from any public charge or tax whatsoever.' It has been so often decided by this court that a charter of incorporation granted by a state creates a contract between the state and the corporators, which the state cannot violate, that it would be a work of supererogation to repeat the reasons on which the argument is founded. It is true that when a corporation claims an exemption from taxation, it must show that the power to tax has been clearly relinquished by the state, and if there be a reasonable doubt about this having been done, that doubt must be solved in favor of the state. (The Binghampton Bridge Case, 3 Wallace.) If, however, the contract is plain and unambiguous, and the meaning of the parties to it can be clearly ascertained, it is the duty of the court to give effect to it, the same as if it were a contract between private persons, without regard to its supposed injurious effects upon the public interests. "It may be conceded that it were better for the interests of the state that the tax-paying power, which is one of the highest and most important attributes of sovereignty, should on no occasion be surrendered. In the nature of things, the necessities of the government cannot always be foreseen, and in the changes of time the ability to raise revenue from every species of property may be of vital importance to the state, but the courts of the country are not the proper tribunals to apply the corrective to improvident legislation of this character. If there be no constitutional restraint on the action of the legislature on this subject, there is no remedy, except through the influence of a wise public sentiment, reaching and controlling the conduct of the law-making power.