1To Thomas Jefferson from David Rittenhouse, 21 June 1790 (Jefferson Papers)
I received yours of the 12th. 14th. and 17th. together with the several papers mentioned, to which I shall give as much attention, and as soon as my health will permit. In the mean time I thought it not amiss to transmit to you such observations as occurred to me on first reading them. I am not quite satisfied with the reasons given (page 1.) for having recourse to motion for a Standard of...
2To Thomas Jefferson from David Rittenhouse, 25 June 1790 (Jefferson Papers)
Since my last letter (and not before) I have read Mr. Whitehursts Book on the Subject of Measures. Amongst the many different ways of obtaining the Same End, the Method proposed by him seems to be a very good one. I see no reason to object to the lenghth he has assigned from experiments, to a pendulum vibrating seconds in the Latitude of London Vizt. 39.1196 inches. You Suppose (page 4.) the...
3To Thomas Jefferson from David Rittenhouse, 2 July 1790 (Jefferson Papers)
I should not have troubled you with my Algebraical Calculations but for your present inconvenient situation. I am however pleased to find your results, tho’ obtained a different way, the same with mine, having never that I remember turned to any Book on the Subject.—The rod used as a Pendulum does indeed require no correction, if it be no thicker than you propose, which will perhaps have...
4To Thomas Jefferson from David Rittenhouse, 4 January 1791 (Jefferson Papers)
Under the Building lately erected by the Philosophical Society there are very large and deep Cellars. Suppose in the midst of one of them, another of 12 or 15 feet deep and 16 feet square was dug and walled and arched over would it not answer the purpose of which we were speaking. A considerable part of the Expence would be saved, and whatever reasonable compensation should be made to the...
5To Thomas Jefferson from David Rittenhouse, 8 May 1791 (Jefferson Papers)
I thank you for a Sight of Mr. Randolph’s Letter. I must Confess I was pleased with Mr. Neville’s account of the Opossum, because it seemed to remove every difficulty on the Subject and at the same time more nearly to connect the Vegitable and animal economy. But I well know with what caution we ought to recive the testimony of any individual. Mr. Randolph’s observations however does not shew...
6To Thomas Jefferson from David Rittenhouse, [ca. 20 August 1791] (Jefferson Papers)
If we consider the same thing in the manner following we shall immediately perceive that the proposition is not new. Since the hole in the vessel may be of any size it may be equal to the intire bottom. The vessel then becomes a Cylinder and the problem is reduced to this, To find the lenghth of a perpendicular Cylinder in which a fluid will descend from the top to the bottom in a given...
7To Thomas Jefferson from David Rittenhouse, 11 June 1792 (Jefferson Papers)
I have read over Mr. Keiths paper carefully, and endeavoured to make out his meaning. He has indeed expressed himself so very loosely that it is not easy to say what he intended. One thing however is clear, that he meant to depreciate the Rod-pendulum; and this he has done in a manner that does no credit to his Candour or Abilities. We have only his assertion, unsupported by any thing that can...
8To Thomas Jefferson from David Rittenhouse, 16 June 1792 (Jefferson Papers)
I have bargained with the owner for the House and Lot on Seventh Street, between Arch and Market Streets, of which you saw the Draught for the Use of the Mint. The price £1600. in Cash, Pennsylvania Currency, Subject to a Ground-rent of 21 Dollars ⅌ An. payable to the Friends Alms-House. If his Excellency the President approves of this purchase the Conveyance shall be made in such manner as he...
9To Thomas Jefferson from David Rittenhouse, 27 November 1792 (Jefferson Papers)
The money granted by his Excellency the Presidents Warrant in July last being appropriated for paying for the House and Lot for the Mint and for purchasing Copper, except 900 Dollars, And Considerable Expences having since arisen for Additional Buildings, Furnaces Horse-Mill and Machines of various kinds I find it necessary to apply for another warrant for the Sum of Five Thousand Dollars,...
10To Thomas Jefferson from David Rittenhouse, 28 November 1792 (Jefferson Papers)
By Act of Congress the Copper Coinage is limited to 150 Tons. This, counting the Ton to be 20 Hundreds, neat Weight, will produce near 8 Millions of Cents, making no allowance for waste in Coining; and supposing the number of families in the United States to be 400,000 will be near 20 Cents to a family. This appears to me to be too great a proportion by more than one half, especially if we...