They must separately describe and separately value separate tracts, unless it is impracticable to do so. If they fail to do so, the assessment is invalid. Young v. Joslin, 13 R.I. 675; Evans v. Newell, 18 R.I. 38; Taylor v. Narragansett Pier Co., 19 R.I. 123; Clark v. Greene, 23 R.I. 118. The proviso in such a case is of no aid in curing the invalidity.

So the expression "Pipes in streets 60,000" is manifestly too indefinite, especially in view of the uncontradicted fact that there were other companies having pipes in the streets of the same town, and that the pipes of the defendant company were less in extent than those of other companies. This description falls directly within the objection held to be fatal in Young v. Joslin, 13 R.I. 677, and in Evans v. Newell, 18 R.I. 38, where the court says: "Again, the description is so vague it in no way identifies the land assessed. The owner could not know from it what lands were assessed to him nor whether the lands of others might be included in the assessment, Such an assessment imposes no duty upon a taxpayer.

The provisions of said act in regard to the assessment and remittance of the tax are for the benefit of the taxpayers and are also mandatory. 1 Cooley on Taxation, 480; Young v. Joslin, 13 R.I. 675; Evans v. Newell, 18 R.I. 38; McTwiggan v. Hunter, ib. 776. Judge Cooley, supra, at p. 480, quoting Field, J., in French v. Edwards, 13 Wall. 506-11, says: "But when the requisitions prescribed are intended for the protection of the citizen, and to prevent a sacrifice of his property, and by a disregard of which his rights might be and generally would be injuriously affected, they are not directory but mandatory.

In Young v. Joslin, 13 R.I. 675, it was held that the statutory provision was for the benefit of the tax-payer, and hence mandatory, and that a failure to comply with it rendered a tax void. Evans v. Newell, 18 R.I. 38, held that a description which does not identify the land assessed imposes no duty upon a tax-payer. Mowry v. Slatesville Mills, 20 R.I. 94, is to the same effect, and in that case an assessment upon separate tracts not separately described was held to be invalid.

Parol evidence cannot be used to supplement an assessment description too indefinite for the identification of the land assessed. Evans v. Newell, 18 R.I. 38. In Taylor v. Narragansett Pier Company, 19 R.I. 123, several parcels of land were assessed as "beach."

As the assessment was not in conformity with the requirement of the statute, it must be held to be invalid. Young v. Joslin, 13 R.I. 675; Evans v. Newell, 18 R.I. 38. As follows: