An Experiment concerning the Nitrous Particles in the Air; By the Same Hand

VI. An Experiment concerning the nitrous Particles in the Air; by the same Hand. —I took a small Gally-pot, such as the Apothecaries in the North of England make use of, where I was when I made this Experiment, and ground the Top of it very smooth and true, and adapted thereto a Cover of blue Slate, which I had likewise ground with much Care. Into this Gally-pot I put equal Quantities of Nitre and Flour of Sulphur, about a Drachm of each. I then fixed on the Cover, putting it into a new Digester; but the Height which I raised the Heat to, and how long I continued it, I do not exactly remember, but believe it was three or four Seconds. When I opened it the Day following, I perceived something had transpired betwixt the Top of the Gally-pot and the Cover; the top Edges of the Gally-pot, where the Glazing was ground off, being discolour'd, though the Nitre and Sulphur were very little diminished as to their Weight; only they were melted into one Lump, which I took out of the Gally-pot. And having set the empty Gally-pot upon a Shelf, upon looking at it the next Day, I found long hoary Hairs, very bright and brittle, all around the ground Edges of the Pot, very specious to behold. After I had admired them a while, I gathered them, and, tasting them, found them to be pure Nitre. I then set the Pot upon the Shelf again, and in three or four Days, still finding there were fresh Shoots made, as large and specious as at the first, I gathered them a second and third time; so that I suppose the Pot Pot would have continued to have shot fresh Nitre much longer, if I had not had urgent Use for it, to make other Experiments in. However, it is to be observed, that I had already gathered more Nitre than I put into the Pot at first; though, as I said before, for what I could perceive, I had taken all or near all the Nitre that I first put in together with the Sulphur, out of the Pot in a Lump. Hence we may have some Conceptions of the Nature of mineral Earths, and how they grow and increase, when once impregnated with the Seeds of a Mineral. This likewise is a Proof of the Quantity of nitrous Particles with which the Air abounds, since the large Quantity of Nitre which I collected out of the Pot, when left empty upon the Shelf, could be supplied by the Air only. N.B. These three Experiments are all that I could save intire out of a great Number which were sent to the Hon. Mr. Boyle, in Answer to a Letter from him to Mr. John Clayton, containing 17 Quare's. Robert Corke. VII. Extract of a Letter from John Rutty, M.D. to Dr. Mortimer, Secr. R.S. concerning the Poison of Laurel-Water. Dear Doctor, Received thine of Feb. 15. with the Transactions No 418 and 420. giving an Account of the Experiments upon Laurel-Water. I wish your Experiments