Was appellant an officer of the city of ■Superior within the meaning of its charter, ch. 124, Laws of .1891? It seems to have been overlooked that such question must be tested by the charter, and that it was decided on general principles governing who is an officer and who an •employee of a municipality. If the same line could be followed here, support could be easily found for the conclusion *621of the trial court, but it cannot, since the charter unmistakably includes firemen among the appointive city officers. That appears by implication by sec. 9, and expressly by secs. 11 and 21.1 Ey sec. 13, the term of all officers of the city is fixed at “ one, two or three years respectively, as herein provided, and until their respective successors are elected or appointed and qualified.” By sec. 11, the power of appointment of firemen is placed with the mayor, as is also the power of removal at his pleasure by sec. 21. Sec. 15 — following sec. 11 which recognizes firemen as officers,- and sec. 13 fixing the term of office of all officers — provides that every officer of the city, except supervisors, aldermen, school commissioners, justices of the peace, and constables, shall be paid an annual salary, and that the common council, in the month of March, shall fix the amount of salary that shall be received by every city officer entitled to a salary, who may be elected or appointed in the city during the ensuing year, which salary shall not be increased or diminished during the term of office for which said officer may be elected or appointed.
The conclusion must follow that appellant was a city officer and entitled to the salary, regularly fixed, which was an incident to his office at the commencement of his term, unless his agreement to take a different salary concluded *622him. The attempt of the common council to fix the salary in February instead of March, and to change it during appellant’s term, was clearly usurpation of power and void.
The authorities are uniform to the effect that in the absence of authority conferred by statute the salary incident to an office cannot be legally changed during an officer’s term, so as to compel him to take less than the salary incident thereto when he entered upon its duties. The salary to be paid to a public officer is not a matter to be fixed by contract, or that can be so fixed, either before or after the term commences. It is an incident of the office, and an incumbent thereof has the same title thereto as he has to the office. A municipality governed by a charter like that of respondent can no more make the salary of an officer a matter of contract than it can make the office itself such a •matter. It cannot omit to elect a person to fill an office and then contract with some person to perform its duties. No one would claim that; yet it is just as plain that it cannot fill an office and make the compensation for performance of its duties a matter of contract. This court very recently passed upon the question involved. Rettinghouse v. Ashland, 106 Wis. 595. The authorities to that effect are numerous. The following are but a small part of them: People ex rel. Satterlee v. Board of Police, 75 N. Y. 38; People ex rel. Ryan v. French, 91 N. Y. 265; Kehn v. State, 93 N. Y. 291; Clark v. State, 142 N. Y. 101; State ex rel. Kercheval v. Mayor of Nashville, 15 Lea, 697; Dyer v. U. S. 20 Ct. Cl. 166; Montague’s Adm’r v. Massey, 76 Va. 307; Larew v. Newman, 81 Cal. 588; Scholfield v. U. S. 32 Fed. Rep. 576; Stocksdale v. U. S. 39 Fed. Rep. 62; Bowe v. St. Paul, 70 Minn. 341.
Having reached the conclusion that appellant was a city officer and entitled to the salary incident to his office at the time his term commenced, the next question is, Did he estop himself by signing the contract, so called, and accepting the *623amount stipulated therein for his services, from claiming any additional amount, notwithstanding it was less than his legal salary? There are authorities to sustain the affirmative of that proposition. Polls v. Yonkers, 102 N. Y. 13; De Boest v. Gambell, 35 Oreg. 368; Brauer v. Portland, 35 Oreg. 471; McInery v. Galveston, 58 Tex. 334; O'Hara v. Park River, 1 N. Dak. 279. The learned trial court seems to have been guided by those cases, but they hardly fit the facts of this case. In each there was an agreement between the municipality and the officer, to take less than the legal salary, made before he entered upon his term of office, or the legal salary was illegally reduced before he took possession of the office, and he received the same by express agreement afterwards. So if we were to approve the rule, that would not necessarily lead to a reversal in this case. It is one thing to agree with an officer before he enters upon his term of office, as to the compensation he shall receive, and quite another to hold over him, while in office, the menace of a removal therefrom unless he consents to a reduction of his legal salary, and by that means induce him •to consent to such a reduction. It is difficult to see how such a proceeding could properly receive judicial indorsement. It is unnecessary to discuss here the mischiefs that .might flow from such a system. That they are numerous •and serious, as regards purity in municipal government, will occur to any sensible man of ordinary experience in public affairs, by a moment’s reflection. That is sufficient to condemn, on grounds of public policy, in a court of justice, any attempt to invoke such a transaction to preclude an officer, forced to become a party thereto, from being bound thereby on the ground of estoppel. The foundation principle of estoppel is justice. Where there'is no element of justice there can be no element of estoppel that can be enforced by the courts.
*624Independent of the foregoing, the better rule is that where the law, as in this case, prohibits a municipality from meddling, during an officer’s term of office, with the compensation he shall receive for his services, the doctrine of estoppel cannot be invoked to thwart it; and that is the rule that has been adopted in this state. Clarice v. Milwaukee Co. 53 Wis. 65; Rettinghouse v. Ashland, 106 Wis. 595.
Notwithstanding the conclusions reached, there is yet an insuperable difficulty in granting appellant relief from the judgment appealed from. That grows out of the fact that we are not informed, by the record as to what salary appellant was legally entitled to. We cannot infer that the salary fixed in February was either more or less than the salary incident to the office when appellant entered upon his duties, or that the amount he received is either more or less than the legal amount. We have no information on the subject. For aught that appears, while appellant was compelled to take less than $65 per month, he may have received more than the legal salary. It stands conceded that the action of the common council in February was illegal, as the charter expressly required the salary to be fixed in March preceding the commencement of the term. This situation is unfortunate for appellant if $42 per month is less than his legal salary, b.ut it is a misfortune that this court is powerless to relieve him from. If there were a bill of exceptions showing what the legal salary was, or if there were a finding of fact on the subject, the situation would be different. As the case stands we must affirm the judgment.
By the Court.— The judgment is affirmed.
Sec. 9 -provides that “ the officers of the city shall be the mayor and two aldermen from each ward, constituting the common council, a treasurer, clerk,” etc., etc., “and such other officers as the common council may deem necessary.” Sec. 11 provides that the mayor, treasurer, etc., shall be elected by the people; that “the other officers shall be appointed by the mayor and confirmed ” by the common council, “ except watchmen, policemen and firemen, who shall take their appointment direct from the mayor without confirmation.” Sec. 21 provides that “every officer elected or appointed to any office, except watchmen, policemen and firemen, may be removed from such office by a vote of three fourths of all the members of the common council; but no such officer, except watchmen, policemen and firemen, shall be removed without cause,” etc.— Rep.