“ It cannot be determined that there is an impairment of the obligation of a contract until it is determined what the contract is, and whether it is a valid contract. If it be valid, it still remains to be determined whether the subsequent proceedings of the city council and legislature impaired its obligation. The ordinance and act were not mere statements of an intention on the part of one of the parties to a contract not to be bound by its obligations. ”

“ Rep. 420, upon the question of diversity of citizenship, it is unnecessary to determine, because there is, in our opinion, a Federal question involved, which gave the circuit court jurisdiction to determine the case without reference to citizenship. ”

“ Rep. 585, 202 U.S. 453, 50 L. ed. 1102, 26 Sup. Ct. Rep. 660; Davis & F. Mfg. Co. v. Los Angeles, 189 U.S. 207, 47 L. ed. 778, 23 Sup. Ct. Rep. 498; Knoxville Water Co. v. Knoxville, 200 U.S. 22, 50 L. ed. 353, 26 Sup. Ct. Rep. 224. ”