When county warrants are at a depreciated value, the said commissioners may in a like manner submit the question whether a tax of a higher rate than that provided for shall be authorized; and in all cases when an additional tax is laid in pursuance of a vote of the people of the county, or for constructing or ordering to be constructed any road or bridge, or for aiding in any enterprise contemplated by the preceding section, such special tax shall be paid in money and in no other manner.
R.L. 1910, § 1609.