This case is presented to the court solely upon the question of the construction and validity of the St. of 1872, e. 306, which is as follows: “ All reservoirs of water, with the dams connected therewith and the lands under the same, used to maintain a uniform supply of water for mill power, shall be assessed for the purposes of taxation in the town or towns where located, at a valuation not exceeding a fair valuation of land of like quality in the immediate vicinity.”
We are unable to construe this statute as requiring merely that che value of land and structures, appropriated for the purpose of creating and applying water power for mills, should be apportioned between different towns, in each of which part only of the works is situated, so that the land alone should be taxed in the town where it is situated, and the artificial structures or appliances for creating the power should be taken as included in the estimate of the value of the power itself, and taxed in the same town as the site upon which it is applied and used; nor can we regard it in purpose and effect as providing, by way of classification merely, that such structures and' appliances shall be estimated only as incident to and included in the value of the power at the site where it is used and valued, wherever located. Lowell v. County Commissioners,
Regarding the statute then as declaring the entire reservoir to be a distinct and separate subject of valuation for the purposes of general taxation, and requiring that valuation to be made upon a basis which excludes all increase of value by reason of the improvements or additions made thereon for the construction and maintenance of the reservoir, however valuable or costly, the question is whether it conflicts with the constitutional provision which relates to the exercise of the taxing power by the Legislature. That provision requires that all taxes levied under its authority be “ proportional and reasonable,” and forbids their imposition upon one class of persons or property at a different rate from that which is applied to other classes, whether that discrimination is effected directly in the assessment or indirectly through arbitrary and unequal methods of valuation. Portland Bank v. Apthorp,
