The power of the legislature to establish special taxing districts upon the lands within which a special tax is to be levied, assessed, and collected is limited by the following rules: (1) There must be some reasonable ground for grouping into a single district the lands composing it, and this reasonable ground must, as has been seen, be that the lands in question will derive special benefit from the public improvement to meet the expenses of which the tax is levied. It follows, therefore, as of course, that the proceeds of the tax may not be used for any other purpose. (2) The tax so levied must be assessed according to a rule uniformly applied throughout the district, which, in its actual operation, will fairly distribute the tax among the several pieces of property affected according to the benefits received or to be received from the public improvement which is undertaken. Whether or not the assessments may be in excess of the benefits is a question to be presently considered, but in any case they must be apportioned generally according to the benefits. By this is not meant that this apportionment must be absolutely exact. This, in most cases, is an impossibility. But, generally speaking, the part of the entire tax borne by each piece of land must agree with the part of the entire benefit received.8

7 George, C. J., in Macon v. Patty. 57 Miss. 378.

8 In Union Refrigerator Transit Co. v. Kentucky (199 U. S. 194; 26 Sup. It. Rep. 36; 50 L. ed. 150) the court say: