Since the decision in 153 Mass. 566, the commissioners therein referred to have been appointed, and have *366made their award, determining the proportion in which the cities and towns concerned shall pay money to the Commonwealth for five years, to meet interest and sinking fund requirements under the Metropolitan Sewerage Loan. This award has been accepted by a single justice of this court. St. 1889, c. 439, § 13. The town of Brookline and the city of Newton appeal: all other parties acquiesce. The ground of appeal is that the commissioners, besides determining the proportion in which each city and town shall pay in the drainage system to which it belongs, have undertaken also to determine the proportionate cost of the two systems, and to determine the sum to be paid by each city and town as a certain proportion of the total. The percentage of the North' Metropolitan system is estimated at 85; that of the Charles River system at 15. Brookline is estimated at 34.32 of the latter, and then again is estimated at 5.15 of the whole. Newton, in like manner, is put at 26.82 and 4.02. It is said that, as the proportionate cost of the two systems was matter of estimate when the award was made, and as the award stands for five years, it may turn out before that time has elapsed that the Charles River system has been charged too large a proportion, and thus that the appellants, by being made to pay a fraction of the whole determined by the charge to the Charles River system, will have to pay part of the cost of the other system. It is suggested that the commissioners have to do only with the proportion of cities and towns in the system to which they belong, and that the total to be paid on account of the systems is a matter of yearly estimate by the Treasurer of the Commonwealth, under §§ 13 and 15.
It'is said, and we agree, that the statute shows a purpose to keep the two systems distinct. On the other hand, the statute contemplates but a single loan by which the Commonwealth is to raise the money for its advances on account of both systems. More advantageous terms could be obtained in that way, and but a single loan has been made in fact. The cities and towns of the two systems are required to pay for a sinking fund, one eightieth part of the whole amount in each of the first ten years. In some way, the proportion of this one eightieth to be paid by each system must be estimated. If the two systems were complete and the cost of each fixed, the proportion would *367be found by a very simple calculation, and it would not matter whether the proportion to be paid by each city and town were expressed as a proportion of the whole or not. But the work is not finished, and therefore estimates must be resorted to. For it is plain that the proportion of one eightieth of the whole loan to be repaid by each system this year, like the proportion of the whole loan to be repaid by each system ultimately, must have reference to the total cost of the two, and not to the accidental expenditures for the particular year.
The statute is unfortunately obscure as to who shall make the estimate of which we speak. Perhaps it would be possible to reconcile the words used with either view. But, manifestly, it is more desirable and more consistent with the spirit of the act, that the commissioners rather than the treasurer should do it. The commissioners are a judicial board who decide what is intrusted to them after-notice and hearing. By § 13 the commissioners shall “ determine for each system the proportion in which each of the cities and towns . . . shall annually pay money into the treasury of the Commonwealth for the term of five years, . . . to meet the interest and sinking fund requirements for each of said years as estimated by said treasurer.” This proportion is a proportion of the entire loan, as we have said, and therefore the proportion which indisputably is to be determined by the commissioners depends upon the proportion between the systems. We are of opinion that the commissioners are the proper board to estimate both elements of the final proportion, that the word “ proportion ” in the sentence just quoted is broad enough to warrant this interpretation, and that there is nothing elsewhere in the act requiring a different one.
The only differences between the appellants’ view and that which we take are in the persons who make the necessary estimate, and the length of time for which it governs the annual payments,— five years instead of one. These differences raise no constitutional question. Moreover, it is to be presumed that the work will be finished, and the actual cost ascertained, long before the sinking fund is paid in. If any rectification is necessary in respect of past payments, we see no greater difficulty in its being made by the commissioners than by the treasurer.
Decree affirmed.