Varieties of Stone. To-day Benjamin Franklin showed me several varieties of stone, which he had in part collected himself and in part received from others. All were formed in the English provinces of America and consisted of:

1. A rock crystal, the largest I had ever seen. It was four inches long and of a diameter of three fingers’ breadth. I regretted it was not transparent but of a dingy, watery color and opaque texture. All six sides were smooth as if ground, and had been found in Pennsylvania.

2. Asbestus stellatus, with fibers radiating out from the center, as described in Wallerius’s Mineralogy, page 145. Its color was a very dark gray, mostly blackish, and felt oily to the touch. It came from New England, where it is found in big stones that are utilized for fireplaces, because it does not change or crumble in the least from the action of fire.

3. Stalactites. These were discovered in a cave near Virginia and were of two kinds: the stalactites conicus which had depended from the roof of the cavern, and the [stalagmite] that had been deposited like a round, uneven, scraggy fungus on the floor of it, where the [calcareous] water had dripped from above. In color they resembled an unclean white.