The plaintiff in error contends that an estoppel was shown. We cannot agree with him in this contention. Even if the allegations of the answer constituted an estoppel, treating the agreed statement of facts as the evidence, as we must, we are compelled to hold that the defense failed through want of proof.

But upon other grounds must not this judgment be affirmed? The law under which these taxes were attempted to be levied and collected has been, by the Supreme Court of this State, declared unconstitutional. Comm’rs of Wyandotte Co. v. Abbott, 52 Kan. 148.

It therefore can have no operation. “An unconstitutional act is not a law ; it confers no rights ; it imposes no duties ; it affords no protection; it creates no office ; it is, in legal contemplation, as inoperative as though it had never been passed.” Norton v. Shelby Co., 118 U. S. 441.

The judgment will be affirmed.