The rays of the sun, particularly in summer, and at noon.

  • 2. The same reflected and condensed, as between mountains, or along walls, and particularly in burning mirrors.
  • 3. Ignited meteors.
  • 4. Burning lightning.
  • 5. Eruptions of flames from the cavities of mountains, etc.
  • 6. Flame of every kind.
  • 7. Ignited solids.
  • 8. Natural warm baths.
  • 9. Warm or heated liquids.
  • 10. Warm vapors and smoke; and the air itself, which admits a most powerful and violent heat if confined, as in reverberating furnaces.
  • 11. Damp hot weather, arising from the constitution of the air, without any reference to the time of the year.
  • 12. Confined and subterraneous air in some caverns, particularly in winter.
  • 13. All shaggy substances, as wool, the skins of animals, and the plumage of birds, contain some heat.
  • 14. All bodies, both solid and liquid, dense and rare (as the air itself), placed near fire for any time.
  • 15. Sparks arising from the violent percussion of flint and steel.
  • 16. All bodies rubbed violently, as stone, wood, cloth, etc., so that rudders, and axles of wheels, sometimes catch fire, and the West Indians obtain fire by attrition.
  • 17. Green and moist vegetable matter confined and rubbed together, as roses, peas in baskets; so hay, if it be damp when stacked, often catches fire.
  • 18. Quicklime sprinkled with water.
  • 19. Iron, when first dissolved by acids in a glass, and without any application to fire; the same of tin, but not so intensely.
  • 20. Animals, particularly internally; although the heat is not perceivable by the touch in insects, on account of their small size.
  • 21. Horse dung, and the like excrement from other animals, when fresh.
  • 22. Strong oil of sulphur and of vitriol exhibit the operation of heat in burning linen.
  • 23. As does the oil of marjoram, and like substances, in burning the bony substance of the teeth.
  • 24. Strong and well rectified spirits of wine exhibit the same effects; so that white of eggs when thrown into it grows hard and white, almost in the same manner as when boiled, and bread becomes burned and brown as if toasted.
  • 25. Aromatic substances and warm plants, as the dracunculus [arum], old nasturtium, etc., which, though they be not warm to the touch (whether whole or pulverized), yet are discovered by the tongue and palate to be warm and almost burning when slightly masticated.
  • 26. Strong vinegar and all acids, on any part of the body not clothed with the epidermis, as the eye, tongue, or any wounded part, or where the skin is removed, excite a pain differing but little from that produced by heat.
  • 27. Even a severe and intense cold produces a sensation of burning.
    “Nec Boreæ penetrabile frigus adurit.”
  • 28. Other instances.

    • We are wont to call this a table of existence and presence.

    XII. We must next present to the understanding instances which do not admit of the given nature, for form (as we have observed) ought no less to be absent where the given nature is absent, than to be present where it is present. If, however, we were to examine every instance, our labor would be infinite.

    Negatives, therefore, must be classed under the affirmatives, and the want of the given nature must be inquired into more particularly in objects which have a very close connection with those others in which it is present and manifest.