Part 55

Mean Longitude 4^h 2° 21′ 58″ } To Dec. 31, Mean Anomaly 4 8 53 56 } 1787, at noon, Place of Aphel. 11 23 28 2 } Paris. Ascending Node 2 12 52 54 }

Mean Motion in Long. in 365 days 4° 19′ 47″ in 30 days 21′ 21″ in 24 hours 42″.7

“The Aphelion and Nodes move according to the precession of the Equinoxes; that is 50″.3 per ann. Inclination of the Orbit 46′ 13″

Log. of greatest distance from the Sun 6.3007701 Log. of least distance 6.2594052 The Log. of the Earth’s mean dist. from ☉ being 5.0000000

“Dr. Halley’s Table of the equation of ♃’s orbit will do very well for computing the place of Herschel’s planet, only subtracting 1/16 part of the equation there found; the greatest equation of this planet being 5° 27′ 16″. So, if from the Log. to any degree of anomaly, in the Table for Jupiter, we subtract 1/76 part of the excess of that Log. above the least, and to the remainder add the constant Logarithm .5647750, we shall have the Log. for ♅ sufficiently accurate. On these principles, I have computed the Right Ascension of ♅, and find both agree with my own observation, to a few seconds.

“I am sorry you have engaged the notice of *******. Men of his principles, with a printing-press at command, are the greatest pests of society.

“My very bad state of health, and a multiplicity of business, have prevented my answering yours as soon as I wished to have done it. I am, Dear Sir, your Friend and Humble Servant,

“DAVID RITTENHOUSE.

“ANDREW ELLICOTT, ESQ. Baltimore.”

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Footnote 232:

The Nautical Almanack.

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The correctness of the calculations respecting the Georgium Sidus, stated in this letter, is noticed in the following extract from one of Mr. Ellicott’s Almanacks.

“The reader will find in this Almanack a continuation of the planet ♅. The elements on which the calculations were made, appear by observation to be very accurately determined, not only by the astronomers in Europe, but by my ingenious friend Mr. Rittenhouse, whose knowledge of the theory and practice of astronomy, is not surpassed in the old world.”

From this time, until his resignation of the treasurership of Pennsylvania in the autumn of 1789, Mr. Rittenhouse appears to have continued to be pretty much engaged in the duties of that office. A short time before this event, the Writer of these Memoirs visited the city of New-York; where the first congress, chosen under the present constitution of the United States, were then convened, having commenced their session on the fourth day of March preceding: and on that occasion, Mr. Rittenhouse addressed a letter to General Washington, then President of the United States, recommendatory of his friend and nephew. Delicacy forbids this relative to present to public view that portion of the letter, which more especially relates to himself: but the introductory part of it is here presented to the reader, for the purpose of testifying the continuance of the high esteem entertained for the truly great man to whom it was addressed, by one who never disguised his sentiments. This extract is as follows:

“Philadelphia, Aug. 14, 1789

“Sir,

“However unwilling I am to add to that multitude of letters which must encroach so much on your precious time, I cannot altogether forbear, without doing violence to my feelings. As we have, all of us, through the course of life, been greatly indebted to the good offices of others; so we are no doubt under obligations to perform the same in our turn, as well with respect to our particular friends, as society in general.

“Mr. William Barton, my sister’s son, knowing that you have heretofore honoured me with your acquaintance, I might, perhaps, say friendship, is willing to believe that any thing I can say in his favour, might have some weight with your Excellency.—

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

“Wishing your Excellency every happiness, I have the honour to be, Sir, with the greatest respect, your most obedient humble servant,

“DAVID RITTENHOUSE.

“His Excellency the President of the U. States.”

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Footnote 233:

In this interval, that is to say, towards the close of the year 1788, Dr. Rittenhouse’s eldest daughter was married to the late Jonathan Dickinson Sergeant, Esq. of Philadelphia.

Footnote 234: