quantities as determined for the past year by meter measurement. This amount, as kindly furnished by the Water Registrar, amounts to 68,200 gallons per day. The amount would then be, 308,200 gallons per day. If to this we add the average amount actually pumped per day for the Highland high service, as shown by the records for May, before the Beacon-hill district was added, which was 82,640 gallons; the total requirements would then be, 390,840 gallons per day, by a most liberal estimate, and only fifty-three per cent of the average daily amount actually pumped in the month of December. There are probably fifty gates in all, required to separate the high and low service, with a difference in pressure on the two faces of forty pounds, and upwards, per square inch; and, unless all these gates are perfectly tight, it is evident that, with such a pressure, the leakage must be very large from the high to the low service; and it is this, in my judgment, and not a wasteful use, that causes the enormous requirements of the high service.

The pumping records show that the hour of greatest draft generally falls between eight and nine o'clock A.M., and that the hour of least draft, between the hours of two and three o'clock, A M. Thinking it might be interesting to know the relative consumption on different days of the week, I have taken considerable pains to compile the following statement:

3

Statement of the average daily number of gallons of water pumped for the high service supply on each day of the week from June to December inclusive, arranged to illustrate the comparative draught on the several days of the week.

From the foregoing statement it appears that the days of the week arranged in the order of the greatest average consumption stand as follows:

The average consumption on Mondays is 19 per cent. greater than on Sundays, and about 8 per cent. greater than the average of the Tuesdays, Wednesdays, Thursdays and Fridays, which do not vary much from each other.

Before the Beacon-hill high service district was connected, the night consumption (from twelve o'clock midnight to five A. M.) was found to average ten per cent. of the day consumption.

Since the Beacon-hill district was connected the proportion of night to day consumption has increased to twenty per cent.

BEACON HILL HIGH SERVICE.

The surveys and plan referred to in my last annual report as being then in progress have been completed, and a full description of the same, and of the method of supplying the district, may be found in my annual report to the Cochituate Water Board in May last.

SOUTH BOSTON HIGH SERVICE.

During a portion of the months of August and September a party under the charge of Wilbur F. Learned were engaged in surveys to locate the buildings and determine the elevations of all door-sills above a plane of fifty-five feet above "tide marsh level." A plan was subsequently prepared similar to that of the Beacon-hill high service, and an estimate of the cost submitted to the Water Board, of supplying the necessary pipes, gates, etc. to connect the present pumping engines with this district, and separate the high from the low service. The following is a copy of the estimate then submitted, viz:

N. J. BRADLEE, ESQ.

OFFICE OF CITY ENGINEER, CITY HALL.
BOSTON, Sept. 7, 1870.

President Cochituate Water Boarà.

Dear Sir :— The following report and estimate relative to supplying the high service of South Boston by the pumping engines, is respectfully submitted. I have drawn the division line between the high and low service substantially as in the case of the Beacon-hill high service, — that is, to include all houses in the high service whose door-sills are at a level of fifty-five feet or more, above "tide marsh level." The districts are shown on the plan herewith submitted, and the number of houses in each. The Independence-square district has only twentytwo houses whose door-sills are above grade 55, and the highest one is at grade 69. This district is all built over. The Telegraph-hill district has three hundred and seven houses whose door-sills are above grade 55, and the highest one is at grade 108. The vacant land in this district will

accommodate three hundred and fifty more houses, so that ultimately there may be in this district six hundred and fifty-seven houses. The present requirements of these districts I estimate at about 120,000 gallons per day, and the ultimate requirements about 200,000 gallons per day. In estimating the size of pipe required to supply the ultimate requirements, I have assumed a maximum draught per hour of thirty gallons per house, which is the amount determined by actual measurement at your house on a washing day. If this draught were kept up for the entire twenty-four hours, the amount consumed would be about 500,000 gallons.

The route for the supply pipe is from the 30-inch main at Tremont street; thence through Dover street over the Dover-street Bridge, and through Fourth street and connecting with the distribution pipes on the easterly side of Dorchester street. The distance is about 7,500 feet.

I find by calculation that an 8-inch pipe of the above length will deliver the maximum amount required as above stated with a loss of head of about twenty-five feet. Assuming the average effective head on the 30-inch pipe to be two hundred feet (and it will be more than that, if the stand-pipe were kept full), — then deducting the loss by friction in the 8-inch pipe, there will be an effective head on the high service distribution pipes of one hundred and seventy-five feet above “tide marsh level,” and as the highest cistern now is about one hundred and fifty feet above said level, there will still be a surplus head of twenty-five feet above the present highest house, and with the stand-pipe full, this would be increased some twenty or more feet.

I am of the opinion, therefore, that an 8-inch pipe will serve amply all the future needs of the South Boston high service.

Should the high service pipes in Dorchester be extended to supply the high districts on Meeting-house and Jones's hills, the proposed 8-inch pipe for South Boston could be connected at Jones's hill instead of at Tremont street. In that case the length of 8-inch pipe required would be about 8,000 feet; but the cost of a syphon would be saved, and as the route is unpaved, there would be about forty cents per running foot saved on the entire length of 8-inch pipe. These two items would reduce the foregoing estimate, making the cost by the Dorchester route about $9,000 less than the Dover-street route. N. H. CRAFTS,

(Signed)

City Engineer.

It was decided by the Water Board, and approved by the City Council, that it would be inexpedient to incur so large an expenditure, until the efficacy of the new 20-inch main had been tested.

DEER ISLAND WATER PIPE.

In my last report I alluded to certain questions which had delayed action in the work of laying the pipe to Deer Island as authorized by an order passed 1869.

The question of what sized pipes would be requisite under certain contingencies, such as the location of the lunatic asylum at Winthrop, and the providing of an adequate fire supply at a proper elevation to suppress fires at Deer Island, were then under consideration by me, and a full report on the subject was made to the Water Board, February 16, 1870, in which I recommended certain changes in the size of pipe previously esti mated upon, and presented a variety of calculations bearing upon the question of the comparative loss of head involved in supplying a definite quantity of water to Deer Island in a given time, through different sized pipes, arranged in various ways, in order to determine what arrangement of them would supply the required amount with the least sacrifice of head, and not exceed in cost the amount already appropriated. The Chief Engineer of the Fire Department was consulted as to the