6. Account of the Terrestrial Measurement of the difference of Longitude between the Observatories of Norriton and Philadelphia; drawn up by the Rev. Dr. Smith, in behalf of Mr. Lukens, Mr. Rittenhouse and himself, the committee appointed by the Am. Philos. Society, for that purpose, agreeably to the request of the Astronomer-Royal of England. Dated, Aug. 17. 1770.
7. The second volume, printed in the year 1786, contains—An Explanation of an Optical deception. Read, March 3. 1780.
8. An Account of some Experiments on Magnetism; in a letter from Mr. Rittenhouse to John Page, Esq. of Williamsburgh. Read, Feb. 6. 1781.
9. A letter from David Rittenhouse, Esq. to John Page, Esq. in answer to one from Mr. Page;) concerning a remarkable Meteor, seen in Virginia and Pennsylvania, on the 31st of Oct. 1779. Read, May 2. 1783. (N. B. Mr. Rittenhouse’s letter is dated Jan. 16. 1780.)
10. Observations[Observations] on a Comet lately discovered; communicated by David Rittenhouse, Esq.[[328]] Read, March 19. 1784.
11. A new Method of placing the Meridian Mark; in a letter to the Rev. Dr. Ewing, Provost of the University. Read, November. 1785.
12. An Optical Problem, proposed by Mr. Hopkinson, and solved by Mr. Rittenhouse. Read, Feb. 17. 1786. (N. B. Mr. Hopkinson’s letter is dated March 16, 1785: the answer is without date.)
13. Astronomical Observations; communicated by Mr. Rittenhouse. Without date.[[329]]
14. The third volume, printed in the year 1793, contains—An Account of several Houses, in Philadelphia, struck with Lightning on the 7th of June, 1789; by Mr. D. Rittenhouse and Dr. John Jones. Read, July 17. 1789.
15. An Account of the Effects of a stroke of Lightning on a House furnished with two Conductors; in a letter from Messrs. David Rittenhouse and Francis Hopkinson, to Mr. R. Patterson. Read, October 15. 1790.