This item, by an unknown author, presents an astronomical sketch of eclipses, some of which could be seen from Philadelphia and Canton, China.

These volumes contain calculations and drawings of an eclipse of the sun, 24 June 1778, and of the moon, 29 May 1779, adjusted to the meridian of Philadelphia. There is also an incomplete duplicate of the calculations for the sun, and a duplicate of the calculations for the moon. An apparently personal reference in the text suggests that Freehauff was a native of Germany.

This small volume records excerpts from British natural philosophy and scientific journals, written sometime after 1799. It covers a wide range of subjects, from astronomy to zoology.

The first volume contains mathematical problems, which appear to be college exercises (1814); the second volume is an essay on the projection of the sphere and spherical trigonometry, including an appendix on astronomy (1812); and the third volume is a lecture on natural philosophy, apparently prepared for delivery [n.d.].

This volume contains calculations of the distances of stars, eclipses, and longitude, made by William Maule, James Cresson, Joseph Jeanes, James James, and Robert Hutchinson, pupils in the Friends Academy, where Roberts was a teacher.