All local assistants not receiving a salary from the State of Alabama shall receive monthly on the audit of the Fire Marshal $.50 for each report of each separate fire reported to the Fire Marshal under the provisions of this article; provided, that the loss by such fire shall exceed the amount of $25.00. In addition thereto there shall be paid to the chiefs of the fire departments or to the mayor in each incorporated municipality or place in which no paid fire department exists or to any other authorized citizen without the limits of an incorporated municipality or place, whose duty it shall have been to make and who has actually made an investigation of such fire and reported same to the fire marshal, the sum of $.15 per mile for each mile traveled to the place of the fire and, where an investigation has been made, a sum not to exceed $3.00 for each day’s service spent in making such investigation. Such fees shall be paid only after conclusive evidence is furnished that such service has been ordered by the Fire Marshal and has been performed in accordance with the provisions of this article, upon itemized vouchers and upon oath.