surveyor of the District of Columbia, and one copy of the plat was sent to the Chief of Engineers. Copies have also been sent for record atthe offices of the surveyor of the District of Columbia and the circuit court at Rockville, a part of the land being in the District and a part in Montgomery County, Md.

The complete survey of the Conduit Road lands, which was com menced during the fiscal year 1890-'91, by Mr. Smead, the superintendent of the aqueduct, has been continued during the last fiscal year as time could be spared from his other duties. This survey was made necessary by the fact that while the north side of the Conduit Road lands was marked by monuments by Gen. Meigs when he purchased the lands in the years 1853-57 for the United States, the south side was not so marked, and in the rapid improvements now being made along the line of the aqueduct encroachments are liable, by reason of errors of surveyors in laying off and subdividing the contiguous private lands unless such monuments everywhere mark the United States lands. This survey has been completed to a point this side of and near Griffith Park Bridge. One hundred and eighty-nine monument stones have been cut and lettered to mark the angles on the lines of survey, and thirty-one of them have been planted.

Surveys were made of a portion of the boundaries of the United States lands near Great Falls and of some pieces of land on and beyond Dalecarlia Hill, projecting from the Conduit Road and reservoir lands. In my investigations of the titles to the aqueduct lands I found that the title papers of several parcels of these lands were neither in the land files at the Department nor in this office, and had probably been either lost or mislaid in the changes that were made in the custody of the aqueduct papers to and from the Department of the Interior and to and from the office of the Commissioner of Public Buildings and Grounds. I have, therefore, procured from the land records of the District of Columbia and of Montgomery County, Md., copies of missing papers pertaining to eighteen parcels of land, and the copies in this office of all the titles to aqueduct lands that are known to exist are now complete. I also found that, about twenty years ago, the title papers to six parcels of land in Montgomery County, Md., were erroneously recorded in the land records of the District of Columbia and that two parcels of land in the District were erroneously recorded in the land records at Rockville. The originals of these papers have been procured from the Department and they have been recorded in their proper places.

In the clearing of the ground over and near the conduit of trees, to prevent their roots from penetrating and splitting the conduit arch, I have saved a large number of locust posts, and have purchased about 20,000 feet of lumber for completing the fencing of the lands pertaining to the receiving reservoir as soon as funds can be spared for the purpose.

THE BRIDGES.

With the exception of the bridge over the Spillway from the receiv ing reservoir, the bridges are generally in good condition, except in respect of their pavements. There are some small leaks in the conduit in its passage over Cabin John Bridge, which are shown by drippings from the arch, but they can not be repaired before I obtain funds for removing the accumulation of deposits in the conduit.

Such repairs as could be made have been made on the bridge over

the Spillway from the receiving reservoir and in the pavements of the masonry bridges. The flooring of the Pennsylvania Avenue Bridge over Rock Creek will be renewed from the appropriation for preservation and repair in the fiscal year just commenced.

A new bridge of masonry is needed where the Conduit Road crosses the Spillway at the receiving reservoir, the old wooden bridge at that point being unsafe for the heavy travel on this road, and a special estimate for it is submitted in my annual estimates.

The asphalt pavements of Griffith Park and Cabin John bridges (bridges Nos. 3 and 4), which were laid many years ago, are in very bad condition and should be replaced by durable pavements of granite blocks, for which a special estimate is submitted.

Measurements of the daily supply to the city.

Hourly and total flow from distributing reservoir for the twenty-four hours ending at 6 a. m., June 25, 1892. City temperature, in the shade, at 2 p. m., June 24, 89°.

Measurements of the consumption and waste of water in the city in the last fiscal year.

Consumption and waste of water in the city, as measured annually in the latter part of June of each year, from 1874 to 1892, both inclusive.

The total population of Washington and Georgetown at the last census (1890) was 202,978. Dividing this number into the total daily amount of Potomac water consumed and wasted in the last fiscal year,

ENG 92-211

as given by the average of the measurements taken during the year, the daily average per capita is found to be 193.4 gallons, The census found, however, that 15,978 of the population of the two cities lived outside of the area supplied with Potomac water. Deducting this number from the total population, and using the remainder, 187.000, as a divisor, we find the daily average per capita within this area to be 209.9 gallons.*

It will have been observed that the dates of measuring the consumption and waste of water in the city during the last fiscal year were quite irregular. The reason for this was that I deemed it best, while the Potomac was either at its low stage or very muddy, not to lower unnecessarily the head of water in the distributing reservoir. This reduction of head could not be avoided when we were removing deposits from the conduit, and the major part of the measurements were taken at these times.

MISCELLANEOUS.

In addition to the foregoing work of the last fiscal year stated under the appropriate headings, the telephone line between the head of the aqueduct at Great Falls, the reservoirs, and this office has been frequently repaired. It has been in use since 1873; it is about worn out, and a new wire is urgently needed. A new gauge made for use in Manhole No. 1 (which is the next manhole below the gates that control the flow of water into the conduit at Great Falls) enables us to regulate with more facility the operations of these gates. The removal of ice that obstructed the flow of water into the feeder at Great Falls and into the screen house at the distributing reservoir was required several times during the winter. A large shed for sheltering the heavy pipe wagon used in cases of breaks in the mains, and the other wagons and carts used in the aqueduct service, was erected in the office yard, and all of the buildings in the yard were repaired and painted. Repairs were made at the high-service reservoir in Georgetown, the dwellings of the division watchmen, the office building, and the fences on the lines of the aqueduct lands.

On reference from the Chief of Engineers, reports on the following bills introduced in the Fifty-second Congress, first session, have been made by me during the fiscal year:

S. 804, to incorporate the Washington and Great Falls Electric Railway Company. (Two reports.)

H. R. 2765, to incorporate the Georgetown, Arlington and Falls Church Railway Company of the District of Columbia.

H. R. 3591, to authorize the Norfolk and Western Railroad Company of Virginia to extend its line of road into and within the District of Columbia, and for other purposes.

S. 1702, to amend an act entitled "An act to incorporate the Washington and Western Maryland Railroad Company."

S. 2045, to provide for the rebuilding of the bridge across Rock Creek at M street northwest, in the District of Columbia.

H. R. 5353, to incorporate the East Washington Crosstown Railway Company of the District of Columbia.

H. R. 5145, to repair the bridge across Rock Creek at M street northwest.

S. 1046, to amend the charter of the Eckington and Soldiers' Home Railroad Company.

H. R. 410, to amend the charter of the Eckington and Soldiers' Home Railroad Company.

S. 2015, to amend the act incorporating the Washington and Georgetown Railroad Company.

*These calculations exclude the increase (unknown) in population since 1890.

H. R. 429, to incorporate the District of Columbia Suburban Railway Company. S. 2174, to incorporate the Crosstown Railroad of the District of Columbia. S. 2405, to incorporate the East and West Washington Traction Railway Company of District of Columbia.

S. 2496, to incorporate the Union Passenger Railway Company of the District of Columbia.

S. 2611, to authorize the Glen Echo Railroad Company to cross the Washington Aqueduct.

Ĥ. R. 7315, to authorize the Glen Echo Railroad to cross the Washington Aqueduct.

NECESSITY FOR FURTHER APPROPRIATIONS.

It is my duty to call especial attention to several works that are urgently needed. Most of them were mentioned in my last annual report.

IMPROVING THE QUALITY OF THE WATER SUPPLY.

Now that the city is everywnere abundantly supplied with water, except at a few points where its proper distribution is interfered with by the small size and the reduction in capacity by internal corrosion of the city's street mains and the service pipes leading from them to residences, one of the most important works to be done in connection with the aqueduct is to furnish the city with better water; or, since the water of the Potomac as brought from Great Falls is, I am convinced, perfectly wholesome at all times, it would be more correct to say with clearer water.

The muddiness of the water supplied to the city arises from the earthy matter carried down to the upper Potomac and its tributaries in storms and most abundanty in winter and early spring, by reason of the alternate freezing and thawing of the ground.

The following table gives the number of days in the four years ending June 30, 1889, on which the water had different degrees of turbidity at Great Falls:

The following table gives the number of days in the four years ending June 30, 1889, on which the water had different degrees of turbidity at the effluent gatehouse at the distributing reservoir, after passing through the reservoir to the mains leading to the city:

It will be observed that the total time that the water was "turbid" and "very turbid" at the distributing reservoir was only about twothirds of the total time that it was "turbid" and "very turbid" at Great Falls, and this great improvement in the water supplied to the city, as compared with its condition when it entered the conduit, was due to the time, short as it was, given for depositing its earthy (clayey) matter in the distributing reservoir.

Filtering the water consumed by the cities of Washington and Georgetown would be enormously expensive (it has been estimated that the first cost of filtration works would be from $600,000 to $800,000, and the annual cost from $18,000 to $43,000, according to the plan adopted). We have now no "head" to spare for it, and we can get no head for it without pumping.

Except by pumping there can be no filtration without loss of head that we now have, and for every foot of head lost in our case there would be a belt of Capitol Hill and a belt of the northern portion of the city that would be deprived of the water that is now supplied to them. Turbidity does not necessarily make waters unwholesome. The clearest waters are sometimes the most dangerous, because they are deceptive, and filtration can, at most, only make waters clear.

During the times of its turbidity the Potomac water has caused resort to the clear but deceptive well waters of the city for drinking purposes, and they doubtless have caused disease which has been attributed to Potomac water, and when the Potomac water has been allowed to flow through the receiving reservoir and mingle with the water of this reservoir there have been complaints of it, but the Potomac water by itself, as brought directly from Great Falls, has never, even in its worst condition, been proved to be unhealthful; on the contrary, it has been generally believed to be one of the best in the country. Even if it should be decided at some time in the future, following the examples presented by the large cities of Europe, to filter the Potomac water, it will be required, in order to save a great part of the cost of the maintenance of the filters to "settle" the water as much as possible before it enters the filters, and the improvement of the receiving reservoir as hereinafter described will still be necessary for the reason that the filtration works, which must be above the heads of the mains that are fed from the lower (the distributing) reservoir, must be at or above the latter reservoir.

Filtration, except by pumping the entire quantity of water consumed and wasted in Washington and Georgetown, being, then, probably out of the question at this time, a comparison of the foregoing tables clearly points out the most important step to be taken for improving the condition of the Potomac water.

It is to provide an additional settling basin, so that when the river is turbid the water can have a longer time for depositing its sedimentary matter before passing into the mains.

This can be done by improving the receiving reservoir.

The receiving reservoir, about 2 miles, following the Conduit road, above the distributing reservoir, has about the same area as the latter, and contains about the same available amount of water.

Its perimeter has a length of about 2 miles. The conduit from Great Falls to the distributing reservoir passes close to a portion of the margin of the receiving reservoir. The part of the conduit that passes around the receiving reservoir is termed the by-conduit. There is an inlet from the conduit to the latter reservoir at its upper end, and an outlet from the reservoir to the conduit at its lower end. They are so