NOVUM ORGANUM 375 



made as a mere history, and without any premature reflection, or 

 too great degree of refinement For instance ; take the investi- 

 gation of the form of heat. 



Instances agreeing in the Form of Heat 



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



II. The same reflected and condensed, as between mountains, or 

 along walls, and particularly in burning mirrors. 



III. Ignited meteors. 



IV. Burning lightning. 



V. Eruptions of flames from the cavities of mountains, etc. 



VI. Flame of every kind. 



VII. Ignited solids. 



VIII. Natural warm baths. 



IX. Warm or heated liquids. 



X. Warm vapors and smoke; and the air itself, which admits a most 

 powerful ind violent heat if confined, as in reverberating furnaces. 



XI. Damp hot weather, arising from the constitution of the air, 

 without any reference to the time of the year. 



XII. Confined and subterraneous air in some caverns, particularly 

 in winter. 



XIII. All shaggy substances, as wool, the skins of animals, and the 

 plumage of birds, contain some heat. 



XIV. All bodies, both solid and liquid, dense and rare (as the air 

 itself), placed near fire for any time. 



XV. Sparks arising from the violent percussion of flint and steel. 



XVI. All bodies rubbed violently, as stone, wood, cloth, etc., so that 

 rudders, and axles of wheels, sometimes catch fire, and the West In- 

 dians obtain fire by attrition. 



XVII. Green and moist vegetable matter confined and rubbed to- 

 gether, as roses, peas in baskets; so hay, if it be damp when stacked, 

 often catches fire. 



XVIII. Quick lime sprinkled with water. 



XIX. Iron, when first dissolved by acids in a glass, and without 

 any application to fire; the same of tin, but not so intensely. 



XX. Animals, particularly internally; although the heat is not per- 

 ceivable by the touch in insects, on account of their small size. 



XXI. Horse dung, and the like excrement from other animals, when 

 fresh. 



XXII. Strong oil of sulphur and of vitriol exhibit the operation of 

 heat in burning linen. 



XXIII. As does the oil of marjoram, and like substances, in burn- 

 ing the bony substance of the teeth. 



XXIV. 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 

 burnt and brown as if toasted. 



XXV. 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. 



XXVI. 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. 



