The excavation for the pipe is made 6 feet wide, with additional space at the bells for calking. The pipes are laid on cross timbers of 4 by 6 inch Florida pine, and are trued and forced into place by wedges on these cross-timbers. Two turns of 1-inch jute are driven into the bell and the joint poured with lead. Each joint takes about 100 pounds of lead. This is afterwards very carefully calked. The earth is replaced in the ditch and rammed well around the pipe by hand, and everything is compacted by water in the most thorough manner.

The average force employed has been about 175 men and 8 carts.

The means of lowering the pipe into place is a tripod, one of the legs of which is double to receive a derrick-winch of 6 tons capacity when used with a double and single block. As many as twenty pipes have been laid in one day by means of the arrangement, which is very convenient.

Records are kept of the labor expended for different purposes, in order that in the end the cost of the various items of the work may be determined.

THE GREAT FALLS FISH-WAY.

It was not until the 12th of June, 1884, that the plans, specifications, and detailed drawings of the proposed fish-way at the Great Falls of the Potomac were received at this office.

Nothing has been done toward the actual construction of this fish-way as yet. I have the honor to be, very respectfully, your obedient servant,

THOMAS W. SYMONS,

Captain, Corps of Engineers.

APPENDIX S S.

IMPROVEMENT AND CARE OF PUBLIC BUILDINGS AND GROUNDS IN AND AROUND WASHINGTON.

REPORT OF COLONEL A. F. ROCKWELL, UNITED STATES ARMY, OFFICER IN CHARGE, FOR THE FISCAL YEAR ENDING JUNE 30, 1884.

GENERAL: I have the honor to submit the following report showing the work accomplished during the fiscal year ending June 30, 1884, upon the public buildings, grounds, and works in the District of Columbia under the charge of this office, together with a descriptive statement exhibiting the number of public reservations under its control, with their location, area, and present condition of improvement.

GROUNDS SOUTH OF THE EXECUTIVE MANSION.

The work in progress for the improvement of the western portion of this park was continued during the year. Low portions of the ground were brought to the required grade with 860 cubic yards of good soil and sown down in grass seed. The roadway provided in the plan for the northwestern section of the grounds, leading from the main roadway around the central ellipse into Seventeenth street, was constructed, and the approach thereto across the sidewalk excavated, curbed, and paved with hard brick set on edge. Two thousand nine hundred and thirty linear feet of additional stone-guttering, mainly 3 feet wide, were laid on the margins of roadways and walks, being constructed with marble and granite spalls from the works of the Washington Monument, and cobble-stones, and 3 large and 16 small additional brick drain traps with iron grating covers were constructed and connected with main sewers by 1,282 linear feet of terra-cotta drain-pipe. Four thousand one hun red and fifty-nine linear feet of new 2 and 3 inch cast-iron waterpipe was laid, 2,442 feet on the east side and 1,717 feet on the west side, connected with the 4 inch street mains and provided with 21 outlets for 14-inch hose-valves, and two 4-inch valves, inclosed with brick manholes and iron covers, were placed in position upon the pipes for the purpose of controlling the supply of water from the mains. Three hundred and twelve additional trees and shrubs were planted, mainly in the western half of the grounds, and a new 3-inch plank box-drain, 12 by 24 inches, was constructed in northwestern corner of the grounds to replace an old one rotted out and unserviceable.

The improved portions of the park received the necessary attention to maintain them in a sightly condition; the lawn surfaces were mown

as frequently as required, and in the winter months were covered with a heavy coating of prepared manure-compost, some 1,645 cubic yards of material being used for this purpose; worn-down portions of the roadways and walks were resurfaced with 632 cubic yards of fine gravel compactly rolled, and their abraded grass borders were repaired with 120 square yards of good soil. A plank walk 24 inches wide was laid on the main walk running east and west across the inclosed portion of these grounds immediately south of the Executive Mansion for the convenience of pedestrians during the winter months when the graveled surface was in a muddy condition. This temporary walk was removed in the spring as soon as the frost had left the ground, and the material stored in the nursery grounds for future use.

MONUMENT GROUNDS AND GREENHOUSES AND NURSERY.

The Monument grounds, with the exception of those portions occupied by the Washington Monument and the shops and stone-sheds appertaining thereto, received the usual necessary care during the year. The main carriage way was heavily coated with fine gravel, which was rolled to an even compact surface after rains, and worn-down places in the other roadways and walks were resurfaced; trees and shrubs were trimmed, mulched, and restaked, and rewired where required; lawns were mown, and gutters and drain lodges freed from weed-growth and deposits of sand and gravel. A good crop of hay was also secured from these grounds (and the Smithsonian Grounds) sufficient for the maintenance of the public animals belonging to this office.

The usual care was extended to the greenhouse buildings, all broken glass being replaced with new, and such of the structures as required it were repainted. Repairs were also made to the benches in the several houses, all decayed wood having been removed and replaced with new materials.

A new palm and croton house, 50 feet long, 21 feet wide, and 15 feet high to apex of roof, was constructed, under contract, and filled with this class of plants taken from a smaller house, which was then utilized as an additional propagating house.

A large tubular boiler of improved design was placed in position for heating the new palm-house and old rose-house adjoining, from which latter the small boiler formerly in use was removed; the objects attained being an increased temperature and a saving of fuel and labor. The new boiler is also of sufficient capacity for heating an additional house when constructed. About 150,000 ornamental foliaged and flowering plants were propagated in the several houses during the autumn, winter, and early spring months, and bedded out in the public parks during the past spring. The collection of crotons, palms, and subtropical plants in these greenhouses were also removed therefrom and placed in the more prominent parks for temporary summer decoration. In the Nursery Grounds necessary attention was bestowed upon the young growing stock, which was pruned, mulched, and transplanted as required. Additions were made to the general stock by the purchase of 1,300 trees and shrubs, which when received were set out in nursery rows for thorough acclimation before final planting in the public grounds. One thousand four hundred plants were also purchased during the year for park decoration. A total of 2,600 trees were lifted from the nursery and transplanted in the various parks during the year, principally in Du Pont Circle, grounds south of the Executive Mansion, and reservations east of the Capitol.