Agreeably to your instructions I arrived at Washington on the 21st of March, and have since that time devoted my attention to the objects proposed by your letter of the 6th of March.

After having very carefully and minutely examined the present state of the Capitol as far as it has been completed, and the foundations of the South Wing, which it is proposed to carry forward this season, I now submit to you the following report,—in which, that my motives in the alterations I shall propose may be fully understood,—I shall be under the necessity of entering into the consideration of the general plan at some length.—I beg leave to add that the remarks to which I pray your attention, have been fully communicated and explained to———, the original author of the plan; a communication which I felt to be due to him, not only as a matter of politeness and ceremony, but as a just tribute of respect to his talents.

In considering the general plan of the Capitol the first remark that occurs is; that by the mode in which the exterior appearance has been connected with the internal arrangement,—a radical and incurable fault has been grafted upon the work, and made an essential part of it. The building has the appearance of a principal floor elevated upon a basement story.1 But in the interior all this expectation is disappointed, the Porticoes lead only to the Galleries and committee rooms, and to get into the Halls of Legislation, it is necessary to descend a flight of stairs.—2

In the internal arrangement of the building another inconvenience results from this error. The grand Vestibule, the Senate chamber, and the Hall of the representatives present but one design. For though the vestibule is circular, the Senate chamber, a semiellipsis, and the Hall of representatives a full ellipsis, and though a variety may be produced by varying the detail of decoration,—the same principle remains,—viz, a high collonade upon a low arcade,—exhibiting a poverty of design, which is as little compatible with the talents of Doctor Thornton as it would have been necessary, had the principal Halls been upon a level with the floor of the Porticos.

To correct the error of landing one story too high is impossible in the present advanced state of the work. I shall therefore dismiss the subject.

The Senate chamber independently of its slight construction and the badness of workmanship is otherwise a handsome room, and should justice be done to the vestibule in the execution,—Europe will not be able to exhibit a more magnificent public Saloon.—It will be worthy of the intention of the building.

It is proposed that the Hall of conference shall be on the floor of the Porticos, which obviates every objection to that beautiful part of the plan; though a basement story will be lost.

I now come to the proposed Hall of representatives which in the original plan occupies with the stair case and a few committee rooms above the Galleries, 40 feet from the ground,—the whole of the South wing.

To this arrangement I think it my duty to state to you my objections, and

1., As they respect use and convenience.

For the commodious dispatch of business by the House of representatives it appears to me that the following appartments should be closely attached to the legislative Hall.—

1., Three or four committee rooms.—

2., A chamber for the Speaker in which he may transact such business with the members or others as does not require his sitting in the chair of the House.—

3., An office for the Clerk of the House.—

4., Offices of the engrossing clerks, 2 rooms.—

5., An apartment for the door keeper where he may assort and keep printed papers for delivery to the members distribute letters and preserve the articles belonging to his office.—

6., Another for subordinate officers of the House.—

7., Closets of convenience.—

8., Fire proof repositories of records.—

9., A lobby sufficient for the convenient retirement of a large number of members from the House, but not adapted to the purposes of a Gallery. The lobbies of the House of representatives and Senate, as hitherto used have been greviously complained against as serious nuisances,—and in the Senate the Vice President has given notice that he should not permit the introduction of strangers into the lobby as heretofore during the next session.—

10., A commodious gallery, not only overlooking the House,—but competely commanded by the view of the officers of the House, and accessible in such a manner that the members passing from one part of the building to another, shall never be interrupted by the persons entering or coming from the gallery.—

My objections to the plan proposed—originally—arise from the want of all these accommodations excepting only of such apartments as may be placed in the South East recess and in the projection between the legislative Hall and the conference room which must of necessity be badly lighted, or in the attic story above the gallery,—a situation remote and accessible only by a flight of 80 steps. Two only of these latter rooms are private, the two others being thoroughfares.—

It has always been understood that the upper story of the north wing would supply the apartments above enumerated,—But as the rooms on the Basement story contiguous to the Senate chamber will probably be appropriated to the use of that branch of the legislature, the upper stories alone will remain for the House of representatives, and a distance of at least 200 feet must be traversed to reach them. It will also be necessary that the members and officers of the House should pass through the people attending in the grand vestibule. This must be at all times unpleasant, and often highly inconvenient.—

I have already mentioned the inconvenience of a lobby calculated to serve the purposes of a gallery. The lobby which is proposed to surround the legislative Hall has all the inconveniences of a lobby within the walls of the House, without the advantage of being controuled by the view of officers of the House. Its size invites a croud, of which the intervening piers prevent the view,—and it is impossible to pass from the House without mingling with the persons in the lobby.

The gallery is inconvenient not only from its massy columns in front, but chiefly from the distance of the front seats from the edge of the area of the House, which unavoidably covers twenty feet of the floor from the sight of the persons in the first row of seats and still more from those behind.

2., As they respect safe practicability.—

The South wing of the Capitol consists of only two enclosures,—An external wall 65 feet high, and an internal enclosure consisting below of an elliptical arcade, and above of a range of 32 massy columns with their entablature. Between these two enclosures there is no possible bond or connection excepting the floor of the gallery, and that of the proposed committee rooms, which are to be lighted by the Attic windows.—Although it is not eligible in any case where it can be avoided, to carry up a wall so thin, so pierced with windows to so great a heighth without support by bond with internal walls or external projections, it would be in the present instance a still more daring attempt, when a domed roof of 90 feet span by 120 is to be carried, and all its lateral thrust resisted at the heighth of 60 feet from the ground.—My ideas on the safety of such a work are best explained by declaring that I want the courage necessary to embolden me to attempt it.

3., As they respect the taste of its architecture.—

It is impossible to deprive a series of 32 columns 25 feet in heighth of an effect singularly striking, and at first sight, pleasantly impressive; nor would the first effect produced be diminished by the frequency of looking at them, were the figure inclosed by the colonade an agreeable one in every point of view. But an ellipsis seen in perspective from any point not lying in one of its axes, has a distorted appearance, the parts on each side being of different figures. Nothing is so well known as that the eye judges of the forms and relative sizes of objects by the habit unconsciously acquired of reducing, their natural appearance in perspective, to orthographical projection. The eye is habituated to judge of circles and of rectilineal figures,—but ellipses occur seldom; no habit exists of judging of their lines perpetually varying in the principle of their progression, and they have always a distorted effect.—Experience proves the truth of this assertion, and therefore both architects and scene painters have substituted in their room parallelograms bounded by semicircles.—

This is a general objection to elliptical rooms. But another objection to the elliptical form of a colonade surmounted by a spheroidal dome occurs which is of more importance.—All the lines of the entablature, and of every other moulding of ever so small projection are lines belonging to parallel,—or to use an incorrect phrase, concentric ellipses. If the lines be accurately drawn, they become distorted in perspective by their having each a separate and different law of curvature, for the last of an infinite series of parallel ellipses is a straight line, equal to the distance of the foci. The bad effect of the attempt even at plain elliptical domes is well illustrated by the sky light of the stairs in the north wing of the Capitol.

If the cieling of the Hall be pannelled (the most beautiful mode of decoration) it will have the distorted effect of every other elliptical pannelled dome, of which in the first revival of arts a few have been attempted, for in each tier there will be only 4 pannels of equal forms and size.

The gallery and lobby have forms the most unpleasant.—The eye always judges of the form of a room by its cieling, for that is the only space in which the view can freely range. When it therefore becomes necessary to sacrifice the form of an apartment to more important arrangements, a cieling—ingeniously disposed—often hides the difficulty that has been encountered. But such an attempt would be vain, where the windows and their piers, considered relatively to the columns which form the opposite bound of the space, are disposed without the most distant reference to lines drawn either to the center, or to the foci, of the ellipsis. And that this is the case in the proposed plan, a slight inspection must evince.

Having spent several days in fruitless attempts to lay down a system of simple decoration for this apartment satisfactory to my habits of taste I have found myself wholly without the talents necessary to the task; and should be very unwilling to labor further in a field in which it is difficult to escape censure, and impossible to reap reputation.

4., As they respect expense.—

A very great expense ought to produce a permanent work:—and yet if the south wing be finished in the manner proposed the whole of the internal work, excepting the arcade, the colonade and its entablature must be of timber,—and of course liable to be destroyed by fire in a few hours: and the expense will be excessive.—

The columns may be either of Timber, cased with plank glued up; of timber frames, lathed and plaistered or stuccoed;—of bricks stuccoed;—of freestone plain or fluted;—or of Pennsylvanian marble.—Of all these materials the latter would probably be the most eligible, and the two first the least so. The columns of the senate room which are of Plaister upon frames are already tumbling to pieces. Brick columns stuccoed are extremely liable to injury, especially when exposed in a public gallery to the hands of a promiscuous croud.—Freestone columns therefore would perhaps, considering their smaller expense, with their permanence, be preferred to Marble, and I will proceed upon an idea of a freestone series of columns of the Corinthian or Attic order. Such a column would be 2 feet 6 inches in diameter and 25 high, the whole order being 30 feet, and could not be executed with their capitals, and placed, under 1200 dollars each column, including every expense. The Entablature 5 feet high, architrave frieze and enriched Cornice, would be a work requiring the most expert workmen, and the most watchful superintendence in the execution. The number of massy stones required would amount to at least 200, and the number of moulds to which they must be wrought would be double that number, for every projection would require a separate mould.—The practical difficulties attending the execution are incalculable. In a circle every stone fits every where, and the last stone which is set, is the only one the size of which is not arbitrary. But in an ellipsis each stone has its determined place from which if it be moved the smallest perceptible distance the line of curvature is destroyed, and the work spoiled.—To calculate the value of time, care, disappointment, and destruction of materials occasioned by this circumstance is impossible,—but at a moderate rate the Entablature supposing the architrave to carry the cieling of the gallery would cost 24.000 dollars.

32 columns at 1200 each are	$38.400
Entablature	24.000
	62.400.

As large as this amount appears, I believe that it would be found scarcely adequate to the completion of the work in a perfect and masterly manner.

5., I might also start objections to the fluttering and scanty light of that part of the room in which the legislative body must sit,—to the impossibility of warming the lobby and the gallery, and to the probable difficulty of speaking and hearing.

Under all these impressions of the imperfections of the plan of the South wing of the Capitol, and after having bestowed much time and study in a vain attempt to preserve its principal features, and to combine with them such accommodations for the use of the legislative body as seem absolutely indispensible,—I have thought it my duty to lay before you an arrangement entirely different from that proposed by the original plan.

This arrangement is explained in the plans and sections hereto annexed.—The form of the Hall is that of the ancient theatre (excedra),3—a form which the experience of ancient and modern times has established as the best for the purpose of speaking, seeing and hearing. The area of the Hall rather exceeds that of the elliptical design, and will hold with ease a body of 360 members, leaving sufficient room on the floor of the House. The principal entrance to this Hall will be from the grand vestibule, through a square lobby and colonade. On the south front will also be an entrance into the lobby behind the Speaker’s chair. This lobby, intended for the retirement of members in order to confer with each other or to receive their friends, will be 80 feet in length, and can never be used as a gallery unless it should be thought proper to break the Wall into an arcade. This I presume will not be done, for if it be thought expedient that Ladies or particular friends of the members should be introduced on the floor of the House, there is ample room for them behind the last row of the seats, where a passage of 5 feet will be left open.

On the East and West fronts are the entrances to the public gallery by means of a stair case in each angle. This gallery,—while it commands a full view of the House facing the members,—is also under the compleat inspection of the officers of the House, whose place is at the north end of the Hall. On each side are also galleries, which may be either appropriated to public use, or reserved for the admission of particular persons.

In the north east angle of the wing is a commodious room appropriated to the clerk of the House, in which his chief clerk may sit, and in the third story above, the inferior and engrossing clerks may be accommodated. The stair case in the recess furnishes the communication with these apartments. At the north west angle is a room appropriated to the use of the Speaker.

In the second story of the east, and in the second and third stories of the West front are commodious committee rooms, to each of which is attached an office for the papers and documents belonging to the Committee. It would have been desirable to have attached to this wing, a greater number of Committee rooms,—but the size of the building forbids it, and should a greater number of committee rooms be wanted, they must be found in the North wing.—

By the necessary result of the general arrangement of the plan, there is an absolute want of light in all that part of the building which lies between the Wings and the center of the building. I have therefore appropriated it to a grand stair case,—to closets,—and to the offices of the door keeper and his assistants. The latter rooms will be lighted from the lower tier of arches of the House, the stair cases from the sky, and the closets by side lights from the staircase and from a small court which becomes necessary for light as well as domestic use,—for it must contain a pump or cistern, and a sink to take off water, and it is a great error in the general design of a building insulated in every side, and which has no cellar conveniences, that no open court of convenient dimensions exists within it.—

On the first floor, independently of the committee rooms, there will be,—a vestibule to the grand gallery, extending from the Stair case to the court, and lighted from the latter,—and a spacious repository of records over the offices of the doorkeeper, to which the access is from the vestibule, and the light from the stairs and open court.

The Hall of Representatives is lighted from the south front, and from a spacious lanthorn light in the center of the half dome.

The whole plan of the Wing as proposed is so arranged as to be capable of being vaulted in every part, and has been so adapted to the external elevation, that every apartment is perfectly symetrical.

I will beg leave to submit one observation on the expense which is supposed to attend vaulted buildings, as applicable to the present.—

The external walls are not altered:

The basement story of the internal enclosure is the same:

The internal enclosure above, contains 1.120 perch of stone work, which if executed with great precision and unusual care, and allowing for arches and nich heads, will cost not more than 5 dollars per perch say 5.600 dollars:

The colonade and entablature would cost at least 62.400 dollars,—the saving therefore will be at least 56.800 dollars in this respect:

The centering of the great dome will not be nearly equal in expense to the framing of a free roof of 120 feet by 96, but allowing it to be equal, no additional expense will arise in that article:

The vault and arches of the great Hall will contain less than 100.000 Bricks. As these bricks must be laid with unusual care, and at a great hight, and must probably be brought from Philadelphia so as to cost on the spot about 9 dollars per thousand,—I will estimate the expense of labor and all materials at 15 dollars per thousand instead of 13 dollars, the expense of the dome of the Bank of Pennsylvania.—at this estimate, the whole vault would cost 1.500 dollars,—which deducted from 56.800 still leaves a savings of 55.300 dollars. The expense of finishing in Stucco is in favor of the vault, as the whole expense of Blocking and Firring, and of all Laths and Nails, is saved.

As to the arches of the Basement story, they are so small in their dimensions, that they will exceed the expense of common well framed floors immaterially. But allowing 5.300 dollars for this excess of expense,—it is still clear that a saving of 50.000 dollars will be effected by the change of plan,—should the Colonade and Entablature be executed in stone; and if in the cheapest manner in timber, of at least 20.000 dollars.—

With these observations, I beg to submit to you the plans which accompany this letter.

I have now to state to you the measures which I have thought it necessary to pursue, in order to commence and prepare the work of the season.

Having understood that the foundation Walls of the South wing, which are carried up to the level at which the Work in freestone is to begin, had not been faithfully executed,—I caused them to be opened in several places, and on different levels, and find that they are on no account fit to bear the weight which is to be laid above them. The stones appear to have been loosely thrown between two thin external casings without mortar, and even without being made to bear upon each other. It is necessary therefore that the whole of this work should be taken down to the first offset; below which I am well informed that the work has been faithfully performed.

I have also caused the foundation Wall of the building in which the House of representatives sat during their last session, and which seems to have been intended for the permanent Basement of the elliptical Colonade,—to be opened in several places beneath the windows.—I have, in every instance discovered it to be of bad workmanship,—but in most of the places which I have examined, it consists also of small stones loosely thrown into a thin casing. I judge this wall to be wholly unfit to carry the weight of the colonade, and of the roof, and as the brick work, above, has been forced from 2 to 6 inches out of perpendicular by the roof,—I do not hesitate in declaring it to be my opinion that the whole building ought to be pulled down to the offset, even if the elliptical colonade be executed. And this must be done, not only on account of the wretched workmanship of the foundation walls, but because, with the best workmanship, no colonade carrying a heavy superstructure can be safely constructed unless its pressure be spread over the whole foundation by means of counter arches. The fissures in the walls of the south wing are entirely owing to the omission of such precaution.

In order that no delay might injure the progress of the work during your absence, I have,—with the concurrence of the Superintendant of the City,—proceeded to such measures as were of the first necessity.

The whole of the foundation Walls which must be pulled down consist of small stones. They are unfit for any purpose but to work up in the Wall with larger stone, and I have therefore contracted with Mr. Elliot, a respectable citizen, to furnish, at the price of $1.75 pr. Perch, 750 perch of large flat stone, none of which are to contain less than 3 feet on the surface, and to be from 5 to 9 inches thick. Mr. Elliot has already begun to deliver the stone. The wharfs at which materials were formerly delivered to the Commissioners being entirely out of repair, and the water in front rendered insufficient by the rubbish thrown into it, I have had the necessary repairs made to these wharves, and they are now fit to receive the rough stone, sand and other light materials. I have also repaired the bridge over the Canal, and mended the road from the upper wharf to the Pennsylvania avenue. The stone recovered in front of the wharves has amply repaid the expense of the work.

In respect to the work to be executed in cut stone, I find that it has hitherto been the custom to provide the stone to the Stonecutter, and to agree with him to cut and set it either by the day or by measurement. This method of doing the business is decidedly against the interest of the public.—All the risks are thrown upon the public,—of loss by labor in the quarry,—by false measurement,—by unsound stone,—by the danger of navigation,—and by faulty workmanship. Each of these operations requires separate and trusty agents;—the attention of the architect to the work is distracted by so many distant scenes of superintendance. If an expensive stone be so faulty in its workmanship as to be rejected,—though the workman lose his labor, the public lose the material. This was found to be the case, when on a trial, some tons of stones were proved to have been buried in the rubbish. Besides, in the œconomy of the material, waste cannot be avoided when the ease of the workman is often interested in cutting up a large block, when another, with somewhat more labor would have answered the purpose.

For these and many other reasons, I beg leave to recommend a contract with Mr. Blagden for the stone, cut ready to be set in the Wall, and I have prepared and delivered the terms of such a contract as I conceive to be for the interests of the work, to the Superintendant.—The stone work of the South wing, erected by Mr. Blagden, and his well known character, seem to authorize the expectation that so important a contract will be well executed by him.—

About 230 Tierces of New England lime have been purchased, which appears to be of a good quality.

In the supply of Scaffolding poles, ropes, sand plank and boards, no difficulty will occur.—There are several sets of good Blocks in the possession of the Superintendant, but two good hoisting Engines must be made.

I have now to report to you the state of the

North Wing of the Capitol.—

It is much to be feared that unless some openings be made to admit air into the Cellars, the Timbers of the floor will, in the course of a few years be consumed by what is termed the dry-rot.—This is the most dangerous of decays, because when it has once established itself in the Cellar story, it never fails to climb to the top of the House unperceived untill the surface of the woodwork is broken, or some material failure in the floors betrays it. For the dry-rot will consume a fixed and painted piece of wood work, untill a shell, one tenth of an inch thick remains, without injuring its appearance in the least. This species of rot almost always begins in unventilated cellars.—It is also on another account necessary that the Light and Air should be admitted to this part of the building. There is not any other means of warming the Senate chamber but by flues either to convey fire, or pipes to convey steam along the floor. The latter are the best, and now universally used in England in large apartments, as the fire flues have long been, in France and Holland.

On the state of repair of the Senate chamber and the necessity of warming it by some other means than those in use, I will report separately should you think it necessary.

The leakage of the roof, which has so much injured the Wall and Cielings of many parts of the house arises from the bad system of carrying off the water; from the bad quality of the lead used; from the joints of the sheets being soldered by which they appear to have been in many places torn; from the broken glass of the sky lights; and from the leakiness of the Cistern.

1., From the bad system of carrying off the Water.—

 All the water is at present collected from evry gutter and discharged into one deep Cistern. After collecting in the gutters along the parapet, it is brought under the roofs, in many gutters, into the internal Area of the roof, so that the chance of leakage is greatly multiplied. It appears to me that the very great length of gutter, and the attempt to keep the roof as low as possible, has prevented a sufficient current being given to the Gutters. The aversion to Water pipes on the outside of buildings has been another cause of this erroneous mode of draining the roof. As, however the cistern appears to have no possible use, and there are corners of the buildings in which Water pipes may be advantageously brought down, I would suggest, as the only means of obtaining a water tight roof,—that the water from A to B be discharged through an external Water pipe at B, into a court yard which must be made in front of the brick part of the building now carried up, and which, though it was built to be pulled down again, ought to remain standing,—because, in the original design no light can be received from the West to this whole pile of handsome rooms and only a scanty light from the north from a window in the corner.

Besides, a court yard is absolutely necessary, somewhere for Privies, and other domestic purposes of Cleanliness, and I have in my plan provided for one for the South Wing.—All the space discharging the Water by this pipe is coloured blue.—

From A to C I propose to discharge the Water through an external pipe in the corner of the recess where it will be entirely hidden. The space supplying this water is coloured yellow.

From D to E I propose to discharge the Water through an external pipe in the other corner of the recess.—This space is coloured red.—

From F to G I propose to discharge the water into the present Waste pipe of the Cistern, which leads to a drain from the Cellar story.—This space is coloured green. All the shingling is remarkably good. It will be a great pity to desturb it, and yet I fear that it must not only be disturbed but destroyed, for I believe that all the gutters must be taken up,—because, though of lead, they are coated with tar and sand so as to prevent the possibility of seeing where they are faulty altho’ nothing is more evident than that they are so.—When laid again, it must be with a much greater descent, and the roof will well admit of it.—

All the Gutters, at present passing under the roof, will become useless. Their lead will go some way towards paying the expense of the new arrangements.

2., Of the bad quality of the lead I have heard only from those who were present when it was laid. It must be examined when taken up.

3., Wherever the sheets have been soldered they must, if laid down again, be cut and groved together, with a good drip.—

4., Sky lights, unless made of thick Coach glass, with Metal frames, always leak. Even then they are great evils, for in summer they heat the house, and in winter they become darkened and often broken by the snow. But Lanthorn lights can always be made tight, their light is pleasant, in summer they can be opened and they cool the house, and in Winter they retain the advantage of a common sash. I propose therefore, as the only effectual method of curing the leaks arising from the Sky lights, to substitute in their room, Lanthorn lights,—that is, lights with upright Sashes and close tops. The sells of the sashes of the Lanthorn must be raised sufficiently to admit of a sloping roof to them instead of the flat, now existing. This will permanently cure leakage. I will remark at the same time that the Sky lights, as now built, are a disgrace to the architect and the workmen in their appearance, and ought to be altered if on no other account.

5., It is difficult to guess for what purpose the Cistern was intended, as it is not provided with any means of discharge.—Were it on the ground floor, or even in the Cellar story, and furnished with a good forcing pump, it could have been made exceedingly useful in case of fire. It is useless now even for the purposes of washing.—The leak in the Library has its rise from this cistern. It must be taken down, and perhaps placed below, and furnished with a forcing pump. The lead is valuable. The Waste pipe will act as a rain water pipe.

Submitting the above to your consideration—

I am, with respect—Your faithful humble Servant—