The treasurer of said city shall set aside the circuit attorney’s fees so turned into the treasury of said city to be used as a contingent fund for the circuit attorney for the payment of the incidental expenses in bringing parties and witnesses from other states or countries and in properly preparing causes for trial, attending trial on changes of venue, attending at the taking of depositions, in printing briefs, and appearing before the appellate courts of the state, and generally such expenses as he may be put to in the proper and vigorous prosecution of the duties of his office. Such fund shall be paid out as needed to the circuit attorney by the said city treasurer out of said funds in the treasury of said city not exceeding thirty-two thousand dollars in any year upon warrant of the circuit attorney. At the end of each year said treasurer shall pay into the general revenue fund of such city any balance that may be in his hands from fees so collected exceeding the sum of one thousand dollars.