FIG. 1. _Stigmaria_ " 2. _Annularia radiata_ " 3. _Rhacopteris inaequilatera_ " 4. Frond of _Pecopteris_ " 5. _Pecopteris Serlii_ " 6. _Sphenopteris affinis_ " 7. _Catamites Suckowii_ " 8. _Calamocladus grandis_ " 9. _Asterophyllites foliosa_ " 10. _Spenophyllum cuneifolium_ " 11. Cast of _Lepidodendron_ " 12. _Lepidodendron longifolium_ " 13. _Lepidodendron aculeatum_ " 14. _Lepidostrobus_ " 15. _Lycopodites_ " 16. _Stigmaria ficoides_ " 17. Section of _Stigmaria_ " 18. Sigillarian trunks in sandstone " 19. _Productus_ " 20. _Encrinite_ " 21. Encrinital limestone " 22. Various _encrinites_ " 23. _Cyathophyllum_ " 24. _Archegosaurus minor_ " 25. _Psammodus porosus_ " 26. _Orthoceras_ " 27. _Fenestella retepora_ " 28. _Goniatites_ " 29. _Aviculopecten papyraceus_ " 30. Fragment of _Lepidodendron_ " 31. Engine-house at head of a Coal-Pit " 32. Gas Jet and Davy Lamp " 33. Part of a Sigillarian trunk " 34. Inside a Gas-holder " 35. Filling Retorts by Machinery " 36. "Condensers" " 37. "Washers" " 38. "Purifiers" CHAPTER I. THE ORIGIN OF COAL AND THE PLANTS OF WHICH IT IS COMPOSED. From the homely scuttle of coal at the side of the hearth to the gorgeously verdant vegetation of a forest of mammoth trees, might have appeared a somewhat far cry in the eyes of those who lived some fifty years ago. But there are few now who do not know what was the origin of the coal which they use so freely, and which in obedience to their demand has been brought up more than a thousand feet from the bowels of the earth; and, although familiarity has in a sense bred contempt for that which a few shillings will always purchase, in all probability a stray thought does occasionally cross one's mind, giving birth to feelings of a more or less thankful nature that such a store of heat and light was long ago laid up in this earth of ours for our use, when as yet man was not destined to put in an appearance for many, many ages to come. We can scarcely imagine the industrial condition of our country in the absence of so fortunate a supply of coal; and the many good things which are obtained from it, and the uses to which, as we shall see, it can be put, do indeed demand recognition.