The figures that are inserted have been drawn upon as small and economical a scale as was compatible with a sufficiently accurate representation of the objects to which they relate. If the reader be desirous of reference to further illustration, he will derive much satisfaction from the invaluable figures of Mr. Sowerby in his British and Exotic Mineralogy, and English Botany, and Woodville’s Medical Botany; as well as from those in Dr. Shaw’s General Zoology, and Bewick’s Histories of Quadrupeds and British Birds. There are also many figures of useful animals in the author’s own work, entitled “Memoirs of British Quadrupeds.” ──────────────────────────────────────────────────────────────────────── ADVERTISEMENT TO THE THIRD EDITION. Since this work was first printed, the author has made in it considerable improvements. The first volume, particularly, contains many additional articles, and more than half of it has been re─written. The plates also have been re─engraved. For the plate of the mountains a new drawing has been made, that the scale might be extended, and many particulars might be introduced which before were omitted. For the plates of vegetables every drawing has been corrected; and, in place of such figures as were most defective, new ones have been inserted. Charlotte─street, Bloomsbury, London, 1st March, 1821. ──────────────────────────────────────────────────────────────────────── EXPLANATION OF THE PLATES OF THE FIRST VOLUME. ─────── FRONTISPIECE. This is explained in pages 236, 237. PLATE I. Fig. MINERAL DEPOSITS. 1. Horizontal beds or strata. a. Veins or dykes. 2. Bending strata. 3. Minerals in detached masses. 4. Disjoined strata. b. A fault. PLATE II. CRYSTALS, &c. 5. Octohedron. 6. Rough diamond. 7. Profile of a brilliant─cut stone. 8. Profile of a rose─cut stone. 9. Plane of a table─cut stone. 10. Plane and profile of the Pitt diamond. 11. Dodecahedron. 12. Rough garnet. 13. Six─sided pyramids, joined base to base. 14 Regular four─sided prism. 15. Six─sided prism. 16. Cube. 17. Four─sided pyramid having a rhomb for its base. PLATE III. SECTION OF ROCKS. I. Primitive Rocks.