Thomas Jefferson Papers

Thomas Jefferson to Nathaniel Ellicott, 24 March 1811

To Nathaniel Ellicott

Monticello Mar. 24. 11


I avail myself of the partial acquaintance between us to which a former occasion gave birth to ask the favor of some information interesting to me. I am desirous of erecting a mill or machine for pulverising plaister of Paris on a small scale, to be moved by water. I remember your being kind enough to shew me your mill once but I do not retain it’s construction in my memory. I think it was on the principle of the powder mill, with pestles lifted by cogs inserted in a horizontal shaft, & falling by their own weight on the stone placed in a trough. was it a single trough common to all the pestles or was there a distinct trough to each pestle? what the size of the trough? the dimensions and weight of the pestle & of what material, wood or iron, made? the length of the cog inserted into the shaft to lift the pestle, & of that inserted in the handle of the pestle? at what distance is the pestle placed from the side of the shaft?1 how many cogs to each pestle, or in other words how many strokes does the pestle give for each revolution of the water-wheel? how near are the pestles to one another? how high are they lifted? is this pounding the only operation necessary, or are there other2 previous or subsequent operations? some idea of the quantity pounded by each pestle in a given time, and indeed I am ignorant of every thing about it, even of the outlines of the framing in which the works are contained and confined: so that the more extensive the information you will be so good as to give me, and the more minute, the greater will be the obligation, and especially adapting your advice to the small scale to which I shall confine myself. there will not be offered more than 40. or 50. tons a year for grinding. half that quantity has already destroyed an excellent pair of mill stones for me, so that I am tired of that mode. I propose to place an overshot wheel for this machine, below the water wheel (an overshot) of my mill, to recieve it’s water by a prolongation of the same water-trough, & to be in operation only when the grist mill is idle.

I hope you will excuse the trouble I thus propose to you andbe assured of the thankfulness with which it will be recieved and of my esteem and respect.

Th: Jefferson

PoC (DLC); at foot of text: “Mr N. Ellicott. Occoquan”; endorsed by TJ.

Nathaniel Ellicott (1763–1841), miller and entrepreneur, was the son of Andrew Ellicott. A native of Bucks County, Pennsylvania, he moved to Occoquan in Prince William County, where he built a toll bridge about 1795. In 1805 Ellicott corresponded with TJ about establishing a road from Washington to the southern states, in which connection TJ visited Occoquan that year. Ellicott and his business partners owned a stagecoach line and a large complex that included flour, toll, saw, and plaster mills. He subsequently lived for a time in Dumfries before moving to Baltimore (Acts of Assembly description begins Acts of the General Assembly of Virginia (cited by session; title varies over time) description ends [1795–96 sess.], 53; John Davis, Travels of Four Years and a Half in the United States of America; During 1798, 1799, 1800, 1801, and 1802 [London, 1803], 230–3, 308–9; MB description begins James A. Bear Jr. and Lucia C. Stanton, eds., Jefferson’s Memorandum Books: Accounts, with Legal Records and Miscellany, 1767–1826, 1997, The Papers of Thomas Jefferson, Second Series description ends , 2:1160; Ellicott to TJ, 7 Jan., 5 July 1805 [DLC], 27 Nov. 1813; Alexandria Daily Gazette, Commercial & Political, 9 Oct. 1811; Colonel Thomas Dorsey Chapter, Daughters of the American Revolution, Tombstone Inscriptions from a Few Cemeteries in Howard County, Maryland [ca. 1960], 4, 7; Baltimore American & Commercial Daily Advertiser, 17 May 1841).

1Sentence interlined.

2Word interlined in place of “any.”

Index Entries

  • Ellicott, Andrew (1733–1809) search
  • Ellicott, Nathaniel; identified search
  • Ellicott, Nathaniel; letters to search
  • Ellicott, Nathaniel; TJ seeks milling advice from search
  • gypsum (plaster of paris); grinding mill for search
  • mills; and grinding gypsum search