Though I had not, the honor of being personally known to you before I left America—I hope it will not be deemed presumptuous in addressing a few lines on some Philosophical subjects—The desire which you have shown to the World for the extension of science, leads me to believe that communications of this sort will not be altogether unacceptable—Africa is a Country but little known though long Noted for the richness of its natural productions—The salubrity of the air at the Cape of Good Hope has been much praised by Physicians—The serenity of the sky by Astronomers.—The beauty & variety of its blooming Heaths & flowers have long pleased the lovers of Botany—and Naturalists have often had their curiosity gratified with accounts of its Insects, Reptiles &c .—One subject however as yet has almost been entirely overlooked—I mean its mineralogy—Gold excepted—we have scarce any account of its minerals, fossils or warm Springs—Kolben, Sparrman & some other writers, have but very slightly mentioned these subjects—Geology being a favorite study of mine—I no sooner set my foot on this promontory than I was pleased with the vast ranges of mountains which are in the neighbourhood of the Cape being provided with a very complete apparatus for making experiments on minerals & mineral-waters, I have been for these two years past (in the intervals of business,) amusing myself in geological researches—The degrees of heat which many of the hot springs in this neighbourhood possess—are considerably great—The water of the Bath situated in E. side of the Cardou mountains near the Elephants river which I visited in march 1800 was 108°—of Fahrenheits Ther:—& that of Brand Valley was 142°—of the same Thermometer—and what is truly curious that copious streams of cold Water should be issuing out of the sides of the mountains not 40 yards from where the hot waters issue out—I have made a number of experiments on both these springs & found their qualities similar and the substances which they hold in solution the same, the principal difference was in the degrees of heat.—The Brand Valley springs are truly an amusing spectacle, I can compare them to nothing more similar than to a number of boiling pots—which have a strong fire under them—The water is as clear as crystal and has no other particular taste or smell than common warm Water, but after standing in bottles corked for some time it contracts a strong Hepatic smell which however goes off again on the bottles being left open—what is very singular the water does not putrify for a great length of time—I have now some of the Water, by me that I brought from the Elephants bath and it is as transparent & sweet as at the moment I took it from the bath—The water of both Baths contains—a large quantity of calcareous Earth.—fixed air—some sulphur, magnesia, marine salt & Iron &c .—The mountains in the neighbourhood of both these Baths are terribly fractured—The strata of Rocks excessively irregular, and every where arround we see the most striking marks of former convulsions—There are several other hot Springs not far from the Cape which I mean to visit in order that I may be able to give an accurate account at some future time of their waters—In these tours, besides remarking the range of the mountains & the materials which principally compose these mountains, I analysed a good many of the specimens which I brought away with me—The stones that compose the mass of these mountains are granite & silicious sandstones & the reigning mineral is Iron—but the bounds of a Letter will not permit me at present to give a particular enumeration—On the Table mountains which are close to Cape Town I have found numbers of marine Shells and on the Lions rump—copper ores, & cinnabar—Sir George Yonge has frequently informed me that he has been creditably informed that there has liquid quicksilver been found among the stones which form the Lions Head, a little below where the signal staff is fixed—Table mountain is of a considerable hight by the measurement which I took of it in June 1797—with the latest improved mountain Barometer at two distances I found the hight to be 3577. 476/100 feet from the level of Table Bay—I mean however to take a still more accurate measurement of the mountains about the Cape, vizt. with two of these Barometers, at the same Instant of time—one at the level of the Sea, & the other placed on the top of the mountain—The stratification of these mountains suggested an Idea which if supported by similar facts in other mountainous countries would lead to confirm what Astronomers have been led to conjecture from a certain motion observed in the fixed stars—occasioned by the slow revolving Poles of this Earth,—a revolution of which according to the calculations of the learned Indian Astronomers—takes up several millions of years—The lower most stratum of these mountains that runs into the sea is almost uniformly perpendicular to the horizon whilest the upper most stratum is perfectly horozontal—from several quarries which are dug in the sides of these mountains & which I have often inspected I found the inclination gradual from the vertical to the horozantal,—Now Some of the most ingenious writers on Geogeny allow that the original stratification of this Earth must have been horozantal as being the natural Order of deposition & so far I am of the same opinion, but when some add that every inclination towards the vertical must be occasioned either by a still lower stratum subsiding which might either be occasioned by internal Earthquakes or being undermined by water and hence the incumbent strata giving way—In this I cannot altogether agree—I believe that in many instances these may be the probable causes particularly where there are evident signs of former convulsions or excavations, but if it should be found in different Country to be a regular Work we must certainly look for some regular cause—But I doubt whether I have not already tresspassed too much upon your important Time & therefore shall reserve my further reflections to another opportunity—In the interim permit me to offer you my sincere congratulations on your accession to The Presidency of the United States Your well known abilities which have been eminently conspicuous in other high stations of Government will insure to America a wise and happy administration—

With the Highest Respect I have the Honor to be Sir Your most Obedient Humble Servt.