Washington Septr. 23d. 1808
The fall of the arch or Vault of the Court room in the North Wing of the Capitol on Monday last, & the death of Mr. Lenthall who was buried in its ruins, must be known to you through the medium of the National Intelligencer & the Monitor in all its circumstances. Among the multitude of vexations, regrets, & business which this unfortunate event has thrown upon me, I feel extremely mortified that I have not been able untill this day, to command the time to write to you, with a perfect knowledge of all the circumstances. The account which appeared in the Monitor of yesterday is minutely correct, & contains all that can be said on the subject. I had drawn it up as the substance of a letter to you, but Mr Colvin was so pressing in his wish to lay before the public a correct statement of the facts, and such improbable & malicious reports were already getting into circulation, that I was prevailed on to give him the manuscript and I hope to be pardoned by you, when I take the liberty to refer to it.—The truth is; that altho’ delicacy to the memory, & to the talents of Mr. Lenthall forbid me to excuse myself publicly by laying the blame upon him; his anxiety to save expence, & afterwards, his fears of the failure of his project were the real causes of the fall of the Vault.
[2 GRAPHICS IN MANUSCRIPT] The account given in the Monitor of the causes of failure will be immediately understood by the annexed drawing.
My directions were to carry,— over the back of the Vault,— walls, the bricks laid arch wise, as at a b c d e f g and to turn a conical arch over each of the spaces between, in order to obtain a level floor for the Senate Chamber. It is true that this method would have consumed twelve times the labor in making centers & that all the Centers would have been lost; but then, it would have been utterly impossible for the Vault to have fallen without throwing down the Butments all round,— which never could have happened.
During my absence however Mr. Lenthall hit upon the Scheme represented in the Section. He made 2 centers on a circular plan 10 feet long, & having turned so much of the arch on the back of the Dome, he then lowered them a little & drew them forward and turned ten feet more, & thus successively till he got round. He then got them out over the back of the cylindrical Arch at the end & thus saved perhaps 500$ in labor & materials. But it is evident that he loaded a part of the dome 1.′1″ wide at A with half the Materials of these Floor arches, weighing about 60 Tons, chiefly stone chips & Brickbats. And yet such was the soundness & strength of the Work that I believe it would have stood even thus injudiciously constructed had he not become alarmed, & lowered the props of the Center at B & C, leaving those at A standing. The consequence was that the Arch settled at those points & of course opened & cracked at A all round, & when at last he attempted to take away the posts at A the common foot of the two Arches at A broke thro the Vault, broke all the Ribs of the Center at that place (for thus we have formed them) & acting upwards against the cylindrical Arch at B, which had stood firm for two months forced it down with it.
The Vault of the Senate Chamber, especially the great Cylindrical Arch, which is 54.f span, & which is quite naked at the higth of 50 feet from the present floor is as firm as a rock, & has a most extraordinary & beautiful appearance. Every other Wall & Arch in the Building is as sound as at the moment it was built.
On the 15h. Septr. Mr Munroe stated to me the balances remaining;—for the North wing 3.049.$ My intention was to strike the Centers of the Courtroom hoping, yet doubting, that the Vault was safe, & if necessary to rebuild it, which would have cost 600 dollars, & to finish the Stairs, & no more,—for which this fund would have been sufficient. But this unfortunate accident has rendered this impossible with so small a fund.—All our Workmen have however offered a Weeks work as a subscription, & many gentlemen have proposed subscribing to an amount amply sufficient to repair & render the Mischief invisible by the meeting of congress. We have no materials to buy, & I propose to proceed upon a different plan, and instead of one great arch on the east side to have 3 arches, resting on the Columns and Pilasters as shown in the plan, and to Rib the Dome in Stone, of which we have plenty on the spot, so as to make an Arch requiring no backing; as in the Octagon Vestibule of the house of Representatives. All this can be done in a Month. I have consulted Mr Munroe,—but without your approbation we are not willing to step forward & lead the thing. To the interests of the city it appears so essential that something of the sort should be done, that the impatience of many of the citizens can hardly be restrained.—
If therefore You would be pleased to express your opinion on the subject as early as possible,—if it does not amount to an absolute disapprobation, the subscription may be immediately carried into effect. In the mean time I am clearing off the rubbish & making preparations, keeping the fund always in View.—
The Walls of the Buildings are now as sound as in 1803 when I first undertook the direction of the Works.
With the highest Respect I am Yours faithfully
B Henry Latrobe
DLC: Papers of Thomas Jefferson.