Thomas Jefferson Papers

Robert Patterson to Thomas Jefferson, 30 November 1812

From Robert Patterson

Philadelphia Novr 30th 1812


At length Mr Voigt has finished your timepiece. The delay, notwithstanding repeated solicitations to the contrary, has been shamefully long; for which no apology can be made but the common one among Mechanicks—a great pressure of business. The workmanship, however, appears to be well executed. A week or so will be necessary to regulate the pendulum; after which it shall be shipped for Richmond, agreeably to your former directions. As, however, there will be some risque on the coast, perhaps it may be advisable to make insurance. The premium will be about 7½ percent. I request your advice on this head.

You have, Sir, I doubt not, seen, & perhaps heard a good deal of the machine called the perpetual motion, which has now for some time been exhibited near Germantown; and presuming that you will not be displeased to see a short description thereof, with the pretended1 rationale of its motion, I shall here make the attempt.

The machine consists (1) of an upright shaft or axis, about six feet long, turning on a steel pivot inserted into the lower extremety, and resting on a piece of hard metal let into a cross-piece, being part of the frame. In the upper extremety of2 the axis is inserted a gudgeon passing into a hole in an upper cross-piece of the frame. (2) The axis, near the upper extremety, passes thro, & is made fast to, a small circular board or cap, about two feet in diameter; from the circumfce of which proceed four small iron chains, equidistant from each other, which support a large horizontal wheel, about five feet in diameter; thro a large perforation in the centre of which the axis passes, but without touching the wheel. (3) On the upper surface of this wheel are placed, on opposite sides of the centre, and about mid-way between this & the circumference, two inclined planes of wood, erected on two oblong bases, perhaps about twelve inches by six, each supported by four small brass wheels: the inclined planes making each an angle with its horizontal base of 45 degrees, & inclining in opposite directions. (4) These bases of these inclined planes are each attached to the axis by slender iron hooks, which, by their elasticity & play3 permit the planes to be moved backwards & forwards a few inches. (5) On each of these inclined planes is placed a long box or carriage, resting on four small brass wheels: These carriages are also attached to the axis, or rather to an iron bolt passing through it, by long, crooked, & somewhat elastick, iron strops, which permet the carriages to descend a small space on the inclined planes, when these are forced forwards. The carriages are occasionally loaded with additional weights, with the view of increasing the velocity and power of the machine.

The above are all the parts of the machine which are considered as essential to its motion—There are indeed three other wheels, of a smaller size, connected with the large one by means of teeth or cogs, which are chiefly intended to communicate motion to any working machinery: all which will be readily understood from the inclosed perspective view.

Now, for the rationale of its motion—as given by the inventor,—for it does actually move—

The carriages on the inclined planes, with the weights placed in them, will, from the influence of gravity, have a tendency to descend: but, from their connection with the axis, being prevented from actually descending, they will act on these planes by what has been called a quiescent momentum, & will thus urge the inclined planes forwards. But as these, from being also connected with the axis, cannot move forwards, their energy will be exerted on the axis, and thus turn it round, with all the wheels connected with it. Now as the machine does actually move, and that with a very considerable velocity (the great wheel making about 40 revolutions in a minute) and as no other cause of motion than the above has been discovered by any of its thousands of visitants, it is considered as a fair inference, that this must be the cause; and as no part of the machine descends, the motion must of course be perpetual.

I shall not affront your understanding by attempting any formal refutation of the above sophistry, which one would suppose could hardly deceive the merist novice in mechanical philosophy; and yet it is mortifying to observe how many of our citizens, from whom better things might be expected, have become dupes to this imposture, and have even published their ignorance to the world. Our city councils have gone so far as to appoint a committee to treat with Readhefer, on the subject of rasing water from the Schuylkill, by a machine on the principles of his perpetual motion, for the purpose of supplying the city. It is however some consolation, that other countries, as well as America have had, & some of them still have, their perpetual motions—In the “Monthly Magazine” for Nov. 1811 there is announced a machine of this kind, then exhibited in Nottingham (England); which from the description appears to be nearly, if not exactly, the same with Readhefers.

“An ingenious clock & watch maker of Nottingham (says the Magazine) is said to have invented a machine, to be applied to the working of silk, cotton, or worsted mills, and which it is supposed will keep such works in their necessary motion without the aid of steam, horse, or water. It consists of a perpendicular wheel that gives motion to another with octangular arms, which acts upon two movable inclined planes, the latter of which operates upon a horizontal wheel, & that upon a cog, which by being applied to the pinion of a mill wheel, sets the necessary works in motion.”

From Mr Short I send you, by his desire the inclosed pamphlet.

I have, Sir, the honour to be, with perfect respect & esteem your obedt Servt

Rt Patterson

RC (DLC); at foot of text: “Thomas Jefferson Monticello”; endorsed by TJ as received 20 Dec. 1812 and so recorded in SJL.

The perpetual-motion machine exhibited near germantown, Pennsylvania, was built by Charles Redheffer, who charged as much as $5 to admit men into his home to view the machine, with no charge for women. Redheffer falsely claimed that his contrivance generated enough movement of its own accord to turn gears without a power source. In fact, the rationale of its motion proved to be a hidden person turning a hand crank (Arthur W. J. G. Ord-Hume, Perpetual Motion: The History of an Obsession [1977], 125–33). Patterson excerpted the description of a perpetual-motion machine exhibited in nottingham (england) from the Monthly Magazine; or, British Register 32 (1811): 401.

The pamphlet enclosed by request of William Short has not been identified.

1Word interlined.

2Manuscript: “of of.”

3Preceding two words interlined.

Index Entries

  • clocks; TJ’s astronomical case clock search
  • machines; perpetual-motion search
  • Patterson, Robert; and astronomical case clock search
  • Patterson, Robert; and perpetual-motion machine search
  • Patterson, Robert; letters from search
  • perpetual-motion machines; and R. Patterson search
  • perpetual-motion machines; of C. Redheffer search
  • Redheffer, Charles; perpetual-motion machine of search
  • Short, William; forwards publications to TJ search
  • silk manufacturing; in Europe search
  • Voigt, Thomas; and TJ’s astronomical case clock search