Thomas Jefferson Papers

University of Virginia: directions for making a clock and bell, 4 June 1826, 4 June 1826

Instructions for the government of the Artist in making the Clock for the University of Virginia.

The bell is to weigh 400.℔, which it is supposed will ensure it’s being heard 1½ mile under any circumstance of weather.

The distance of the hollow cylinder in which the weights are to descend, and it’s oblique direction from the dial plate has rendered necessary an outline of the ground plate and elevation of the parts. of the building where it will be placed; this is drawn on lined paper, in which every line counts a foot, and every 10th line is more strongly drawn to facilitate counting by which the measures, are to be taken and not all by scale & compass.

The cylindrical space in which the weights descend is of 5. feet diam. and 48.f. depth, that is to say from the level of the center of the dial plate to the ground.

The tympanum of the Pediment, in the center of which the dialplate is to be placed, is 42. feet in the span, and 9 f–4 I in it’s perpendicular at this aper, that is to say the naked of the tympanum within it’s cornice. such a triangle admits a circle of 52.I. radius to be inscribed within it. so that describing in it’s center the dial plate of 30.I. radius, & around that the architrave 10.I. wide there will remain a clear space between the architrave and cornice of the pediment of 12I. in the points where they approach nearest. but the dial plate must be as much wider than the 5.f. which it shews as to fill a rabbet of ½I. at least in the back face of the architrave in which it may be firmly imbedded. it must be metal of course as wood would go too soon into decay.

The face of the tympanum will be exactly over the line ab. and c. isthe center of the cylinder of discent for the weights. the direction of the cord it is supposed may be from d. to e. where an aperture in the wall may pass it on to the pully or point of suspension. thus requiring but a single change of direction. this however is for the consideration of the artist.

The bell is to be suspended on an iron gallows, sufficiently strong, mount’d on the ridge pole of the pediment, perpendicularly over the clock works, no ornament is to be given to it nothing which may attract notice or withdraw the attention of the observer from from the principal object. somewhat in this simple style.  

[GRAPHIC IN MANUSCRIPT] it must be free to be rung independently of the clock.

the weights of the striking as well as the going parts descend in the same cylinder, but the ringing rope may go down the opposite cylinder at f. which is occupied by winding stairs. the winding up of the clock must be on the back side of the works within the hollow of the roof.

and there also means must be furnished of setting the hands.

Th: J.
Monto June 4. 26


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