REPORT

OF

THE ARCHITECT OF THE CAPITOL.

ARCHITECT'S OFFICE, UNITED STATES CAPITOL,

Washington, D. C., October 1, 1877.

SIR: In compliance with your instruction of the 3d ultimo, I have the honor to submit the following report relative to the Capitol, the Capitol grounds, and other public works under my charge:

CAPITOL.

The Supreme Court room and offices connected therewith, the walls of the Rotunda, many of the passages and committee-rooms, and most of the exterior of the central portion of the building, have been painted.

The belt of the Rotunda, intended to be enriched with basso relievos, is being embellished in real fresco, representing in light and shadow events in our history, arranged in chronological order, beginning with the landing of Columbus and ending with a period of our revolutionary history.

A hydraulic elevator has been placed in the Senate wing. Also, new steam-boilers are being placed therein. The return-pipes connected with these boilers have been renewed and placed in ducts with irou coverings, which render the pipes under the floor easy of access for repairs. The boilers were constructed and connecting steam-work done under the immediate superintendence of Mr. Hayden, engineer of the Senate wing.

An additional flue has been constructed to furnish fresh air to the Senate galleries.

The question of improving the heating and ventilation of the Repre sentative Chamber engaged so much attention during the last session of Congress that a committee on this subject was appointed under a resolution of the House.

After much consultation by them, it was ordered that the whole subject be referred to a commission of gentlemen named by them for examination and recommendation as to what changes, in their judg ment, should be made.

This commission, after a thorough examination of the apparatus and

various plans and reports proposing changes, finally recommended as follows:

WASHINGTON, D. C., February 2, 1877.

The board find that the measures which have been taken to give an increased supply of fresh air to the Hall of the House of Representatives, in accordance with its recommendation in its previous report, have been followed by good results, and that the test of actual experience, during both cold and warm weather, has shown that the Hall can be satisfactorily heated and ventilated with the system now employed, namely, that of upward currents, and that this can be done without causing discomfort to the occupants.

The recommendations of the board heretofore presented were intended to meet the great want existing, namely, that of an increased supply of air without the production of unpleasant draughts, and also to remove or mitigate certain sources of impurity which were found to exist in the basement of the building.

These recommendations have been only in part carried out, owing to the want of funds, for, although the sum estimated for by the board, namely, $8,000, was duly appropriated from the contingent fund of the House at the close of the last session, yet it appears that this appropriation was only partially available, since the contingent fund was exhausted.

For this reason it has been found impossible by the architect to provide the means for that increased supply of fresh air to the galleries which the board consider as necessary.

The board has collected information as to the practical results obtained in large halls of assembly in this country and in Europe by the systems of heating and ventilation adopted, and from these, as well as from the observations and experience of its members, it has arrived at certain conclusions as to what should be done looking to the permanent arrangement for heating and ventilating the south wing of the Capitol, which may be stated as follows:

1. That it is not desirable to change the present or upward system of ventilation of the Hall of the House of Representatives for any system of so-called downward ventilation, and it is not possible to apply any so-called natural system of ventilation, by means of windows and openings in the ceiling and walls only, to a large assembly hall

like this.

2. That while the quantity of fresh air which can now be supplied to members on the floor without causing unpleasant draught is probably sufficient under ordinary cir cumstances, it is desirable that there should be means to increase it when needed. 3. That the supply of air to the galleries should be largely increased, and that there should be means provided for furnishing cooler air to the galleries than is supplied to the floor of the Hall.

4. That the system of brick flues beneath the floor of the House should be removed, and galvanized iron flues substituted so far as necessary.

5. That a duct should be constructed to bring the fresh air required for the use of the House to the injecting-fans from a point on the lower terrace and through an ornamental shaft about thirty feet high.

6. That an attempt should be made to regulate the amount of moisture in the air supplied, and to cool the air in warm weather.

7. That for this purpose, as well as for other reasons, the course of the present freshair duct should be changed, and the heating coils removed from their inaccessible and inconvenient position, and that the point for admission of fresh air beneath the floor shall be central, instead of in one corner, as at present.

8. That additional means of ventilation should be supplied for the upper lobbies. 9. That an attempt should be made to so arrange a system of outlets for foul air in the roof that the wind can only produce an increased flow of air outwardly.

If this can be done successfully, the exhaust-fans now in use will become available for ventilation of the basement and lobbies.

10. That means of communication by a system of electric signals be provided between the floor of the House and the engine-room.

11. That the whole matter of heating and ventilation of the south wing of the Capitol should be placed under the control of one person, who is to be held responsible for their proper working. Under the present system, or rather want of system, the board do not believe that any apparatus can be made to work satisfactorily.

If it is desired that the board shall continue to interest itself in the heating and ventilating of the House, and in the devising of the best means of carrying out its recommendations, it is extremely desirable that the person who is to have charge of the apparatus when completed should be in some way associated with the board, not only to carry out the experiments and observations which it may deem necessary, but to become familiar with what is to be done, and with the apparatus and machinery decided to be best adapted for doing it.

12. Plans have been prepared by the Architect of the Capitol for the alterations

recommended, and these are herewith submitted. The total cost of making these changes, and of putting the heating apparatus in good order, including the purchase of 20,000 feet of new steam-pipes, is estimated at $33,000. All of which is respectfully submitted.

JOSEPH HENRY,

THOS. L. CASEY,

Secretary of the Smithsonian Institution, President of the Board.

Lieutenant-Colonel Corps of Engineers, Member of the Board.

Surgeon United States Army, Secretary of the Board."

As provided by law, the changes and improvements recommended above have been made, which are thus described by Mr. Robert Briggs, engineer, who has ably assisted in this work:

During the recess of Congress, the following changes have been effected in the arrangements of the apparatus for ventilating and heating the south wing of the United States Capitol.

The necessity of pure and fresh air supply for the purpose of ventilation being fully admitted, there has been a change made in the place from which the air was taken previously, by the construction of a subterranean duct or passage, leading from a point 200 feet direct from the building, and about the same distance from the streets, below the terrace, west of the Capitol, to the fan, which injects the air for the Hall of Representatives.

It is believed that in this location the air will not have been vitiated or impaired in purity in any degree, either from the Capitol itself, or from the city beyond the grounds; and when the tower, of 30 feet height, proposed by the commission of offi-' cers of the United States, to whom this question of ventilation was referred, shall have been finished, it is deemed certain that the purest air attainable in the city of Washington will have been used for the ventilation of the Hall.

The immediate and especial advantage of this alteration will be the avoidance of odors from the machinery or boilers, which are located in close proximity to that part of the building where the supply-mouth of the fans was in the first instance.

The large fan (16 feet in diameter) and its engine, (of about 60-horse power,) as originally constructed, have been put in as good condition as when new, twenty years ago, and again possess the capability of supplying 50,000 cubic feet of air each minute during the cool season, and 100,000 cubic feet in the same length of time in hot weather when the necessity for the larger volume exists, to give relative comfort.

An entire change has been made in the ducts leading from this fan. A great deliverymain now passes from it in the cellar, to near the center of the building, where one of the large central rooms has been taken for a heating-chamber, and provided with coils of pipes, to be heated by steam; after passing this chamber, the warmed air enters a second large chamber, where it can be deprived of dust, supplied with desired moisture, and otherwise treated, to render it more pure and healthful.

From this chamber the current of air separates into two ducts, which lead upward through the basement story of the building to the two parts of the Hall situated on either side of the central passage. Each of these ducts terminates, that is, ceases to be a main, in an inclosed chamber or end beneath the floor of the Hall; which chamber bas openings in several directions.

These openings are mouths of branches of distribution, and serve to place under control the supply of air to any part of the Hall.

Some of them lead immediately to the space under the circles of the desks, which is now entirely open, the brick ducts and passages, which bad become disused in the previous changes of desk arrangement, having been cleared away and removed. Within this circle the distribution of air can now be made general and equal all over the floor. Other openings from the chamber lead to the space without or beyond the circle of desks; while yet others lead to the galleries exclusively, by large air-passages passng upward in the walls of the coat-rooms, so that a great independent supply of air is provided for the galleries.

This gallery supply is in addition to former provisions, and will unquestionably relieve the ventilation of the hall, by substitution of fresh for vitiated air in the galleries themselves, by preventing a diffusion of vitiated air into the body of the ball, and especially in tending to preclude currents of air by making the supply general throughout the room.

To give some idea of the magnitude of the provision for supply of air to the Hall, in

the way of air-ducts of passages, it will be stated here that the main air-supply duct, leading to the fan, has a cross section of area of 120 square feet.

The main delivery-duct, from the fan to the heating chamber, has 80 square feet of area. The two mains to the floor of the Hall have each 40 square feet of area. Of the distributing branches under the floor of the Hall, those which lead to the south gallery (two in number) will have each 14 square feet; those leading to the north gallery (also two in number) each 7 square feet. The sizes of these distributions will be such as to require the full supply from the delivery-branches. These distributing-branches under the floor of the circle of desks, and under that of the galleries, have been made of sheet iron, and so arranged that distributions from all branches are controlled by regulators to insure proper local action.

For the escape of foul air from the Hall the former provision of distributed openings in the ceiling has been thought ample and well arranged to remove the current uniformly over the whole surface. But the inadequate dimensions of the outlet for discharge above the roof has been corrected by the construction of a louvered ventilator, arranged to be closed at either side, in opposition to the winds. This ven.ilator has more than 140 square feet of unobstructed area on either side for the efflux of air. With these provisions for supplying and getting rid of large volumes of air, the means of controlling its temperature, at all times and at any moment, has been materially amended, especially when the condition of the great coil and its chamber, as they formerly were arranged, is considered.

In the new arrangement of coil-chamber the materials of the old coil, most of which were unimpaired by time or service, were reconstructed to form four sections or masses of pipes, containing in all 45,000 feet, or nearly nine miles of pipes of one inch diameter, (nominal.) These sections occupy the lower part of the chamber, and are inclosed by a sheet-iron covering separating them from the upper part. In front of these sections (in the direction in which the air enters) and of the space above them is placed a partition of iron louver blinds, so that by opening the lower blinds the cold air comes upon and presses among the pipes, and is warmed, or by opening the upper blinds the air enters above, and passes over the coil. These contrivances enable the air to be tempered to any degree of warmth at any moment.

When properly manipulated in cool weather, warmer or cooler air is at the command of the operator, as occasion may require, without waiting for heat to be imparted to or removed from the heating coil; while the pipes are not open to the difficulty usually attending steam-heating, of the likelihood to freeze the lower tubes in the attempt to regulate the heat of the air-supply.

After the hot and cold currents in proper proportion will have passed through or above the coil, they are commingled in the chamber behind the coil in part, aud in the preparatory chamber afterward, until one current of uniform temperature is provided for supply to the distributing ducts and branches.

The appliances for treatment of air, regulating its moisture, and for cooling it in summer, have been essayed, but with the knowledge of repeated effort in these directions, accompanied with repeated failure of any essential or important result, it can only be claimed that the success of these appliances is problematical. The room, however, has been provided for prosecuting the trials without interfering with the working of the apparatus at any time. Both steam-jets and water-jets have been furnished to supply any amount of moisture desired.

There being no loss of heat by the walls or floor of the Hall of Representatives at any time or in any season, and the loss of heat at the ceiling being overcome by the great and constantly ascending current of vitiated air from the Hall. (supposing the adequate ventilation, equal to 50,000 feet per minute, which empties the Hall each 10 minutes, were provided,) it follows that no hot air is ever needed for its ventilation. That is, that 70° temperature of air is too warm to introduce when the Hall is crowded, in the cold weather, and 65° to 68° are needed to keep the room down to 70°, if this be the accepted temperature of comfort.

Consequently, the difficulty to be encountered is, how to introduce the large volume of comparatively cool air, needed to procure freshness to the senses, without having currents blowing upon the persons occupying the desks or benches.

To solve this difficult problem every advantage has been taken in the changes made this year to make available any portion of the room not occupied by sittings.

Within the circle of the desks the risers of the platform have been left perforated as before, but means have been taken to control the amount of air entering at them, so that no defined currents along the floor shall be propagated. The sides or risers of the aisle-steps have also been provided with numerous perforations, so disposed that currents from them shall meet and be diffused by opposite currents.

About the Speaker's desk numerous openings have been made, with every precaution for diffusing the emerging currents; and it is in contemplation to put registers or small platforms near many of the desks, which shall be perforated, to allow escape of air.

Beyond the circle of desks the large registers are retained in the corners as the best

way of preserving equality of distribution in these localities, but the great reliance is on the numerous small registers in the walls, which will now be adequately supplied with air.

In the coat-rooms the small registers also will now suffice in amount, while in the galleries the air-supply is now provided to be equal, if necessary, to that elsewhere in the hall.

It may not be that a perfect success in ventilation will be attained at the first trial of the new arrangements, but it is certain that the control of the means is now so completely in the hands of those who direct the system that any change can readily be effected at will.

As the heating and ventilating apparatus is now arranged, it is capa ble of supplying all the fresh air that may be required, and is so adjusted as to furnish warmer or cooler air, as causes for such changes in the temperature in the chamber may occur.

With attentive and intelligent management, I feel confident that this new arrangement can be made to give all the satisfaction the nature of the case will admit; that is, the air will be furnished in adequate quantities; will be chemically the same as that of the external atmosphere, and will be delivered at any fixed temperature that may be required.

It is proper to state here that I feel indebted to Mr. Lannan, engineer of the heating department of the House, for his cordial and intelligent co operation in the changes.

CAPITOL GROUNDS.

For full information relating to the work done on these grounds, and showing their present condition, I insert a portion of the report made to me by Mr. Cobb, engineer:

In making the third annual report of the improvement of the Capitol grounds, according to the plans of Mr. Fred. Law Olmsted, landscape architect, and carried on under your direction, I have the honor to state that the work has proceeded satisfactorily, and as rapidly as the amount appropriated would allow.

In consequence of the appropriation being small, ($125,000,) the men have been kept on half time during eight months of the year.

The number of names on the pay-roll is 126. From June 30, 1876, to June 30, 1877, there were 23,3284 days' labor performed by the men, and 2,7714 days' work of horses, at a cost of $54,064.85.

This includes, however, $7,473.04 expended on the rolls for ventilation of the House of Representatives, and $1,585.45 paid by vouchers for special work.

All material has been purchased at the lowest market-price, and fully up to the standard called for in the various contracts and specifications.

The intense heat during the summer of 1876, parched part of the grass sown during the spring, and some of the plantings were res-eded in the fall. Most of the trees and shrubs survived, the total loss being two large and twenty-two small trees. The lawns are kept closely cropped, and the sod is exceptionally firm and compact.

On account of the total lack of police, the depredations among the small shrubbery have been numerous-one hundred and fifty shrubs being taken from various parts of the grounds, and one hundred plants removed from the fountains in the east park alone. Five of the trees mentioned above as dying were destroyed by boys. A large number of cattle have been caught trespassing, but, as most of the depredations were committed after working-hours, the greater part could not be prevented.

During the year thirty-three large and fifty small trees have been moved by the trucks.

One hundred oriental plane trees and one hundred and eighty-six choice plants were imported. Altogether 7,837 plants and trees have been set out.

Since the last report, the drives, then under contract, leading from First street west to the top of the hill, both north and south, and the approaches from Delaware avenue north, and New Jersey avenue south, have been laid with bituminous concrete pave

ments.

This work, as a whole, is satisfactory, but in parts exhibits a tendency to soften ander the heat of the sun, and in some instances has required extensive repairs, which the contractors have promptly made, the terms of their contract requiring them to keep the pavement in good order for three years.

That laid on the west end of the north drive is especially faulty in this respect, but the rapid evaporation of its volatile oils may bring it to the right consistency in another year.

The pavement laid at the Delaware avenue entrance is of little value, except its base