2. “Calculation of the Transit of Venus over the Sun, as it is to happen, June 3d 1769, in Lat. 40° N. Long. 5^h. W. from Greenwich:” communicated 21st of June, 1768. 3. An Account of the Transit of Mercury over the Sun, Nov. 9. 1769, as observed at Norriton, in Pennsylvania, by Dr. Smith, and Messrs. Lukens, Rittenhouse, and O. Biddle, the committee appointed for that purpose by the Am. Philos. Society: drawn up and communicated, by direction and in behalf of the committee, by Dr. Smith—July 20. 1769. 4. Observations on the Comet of June and July, 1770; with the elements of its motion and the trajectory of its path; in two letters from David Rittenhouse, M. A. to William Smith, D. D. Prov. Coll. Philad.[326] Communicated, Aug. 3. 1770. ----- Footnote 324: It is said of the celebrated Roger Cotes, by his friend and patron, the learned Dr. Richard Bentley, in his inscription upon the tomb of that great philosopher, at Cambridge, that— “_Pauca quidem Ingenii sui pignora reliquit, Sed egregia, sed admiranda_:” In like manner, though the writings of Dr. Rittenhouse are neither numerous nor extensive, some of his works are, nevertheless, so excellent and admirable in their nature, they exhibit such proofs of transcendent genius, that they will immortalize his name. And, as Cotes was prematurely taken away by death, or, as expressed in his epitaph, “_Immaturâ Morte præreptus_;”— so, the actual term of Rittenhouse’s life may be considered as having been much shortened by sickness. Franklin, who lived twenty years longer than our astronomer, published little in philosophy; yet this circumstance does not derogate from his claims to the character of a philosopher. Footnote 325: A second edition of the first volume was published in the year 1789, in consequence of the extraordinary demand for that book, by reason of the very important papers respecting the Transit of Venus, contained in it. Footnote 326: Some further remarks respecting this comet, than those contained in Dr. Rittenhouse’s communication, here referred to, will be found in an extract which has already been given, of his letter to the Rev. Mr. Barton, under the date of July 30, 1770. ----- 5. An easy method of deducing the True Time of the Sun’s passing the Meridian, per clock, from a comparison of four equal altitudes, observed on two succeeding days; by David Rittenhouse, A. M.[327] Communicated by William Smith, D. D. Prov. Coll. Philad.—Aug. 17. 1770. ----- Footnote 327: