The Seventeenth Century 93 



water and air are not utter enemies thereto, appears from the dashing 

 of salt-water in a dark night, and a hot season, when the small drops of 

 the water, struck off by the motion of the oars in rowing, seem sparkling 

 and luminous. We have the same appearance in the agitated froth of 

 the sea, called sea-lungs. ^ And, indeed, it should be inquired what 

 affinity flame and ignited bodies have with glow-worms, the Luciola, 

 the Indian fly [Pyrophorus], which casts a light over a whole room; the 

 eyes of certain creatures in the dark; loaf-sugar in scraping or breaking; 

 the sweat of a horse hard ridden, etc. Men have understood so little of 

 this matter, that most imagine the sparke, struck betwixt a flint and 

 steel, to be air in attrition. But since the air ignites not with heat, yet 

 apparently conceives light, whence owls, cats, and many other creatures 

 see in the night (for there is no vision without light) , there must be a 

 native light in air; which, though weak and feeble, is proportioned to 

 the visual organs of such creatures, so as to suffice them for sight. 



The relation between light, heat, and flame must have presented 

 many perplexities, for it is again discussed in the Novum Organum ^ 

 (1620) without adding new ideas. The best example of Bacon's 

 deductive approach to the study of phenomena is to be found in 

 the Sylva Sylvarum or A Natural History in Ten Centuries, pub- 

 lished in 1627, In Century I, section 30 deals with " the commixture 

 of flame and air and the great force thereof." Bacon wrote: " As 

 for living creatures, it is certain their vital spirits are a substance 

 compounded of an air and flamy matter." Like oil and water they 

 " will not well mingle of themselves; but in the bodies of plants, 

 and living creatures, they will." 



This statement is apparently a recognition of the intimate rela- 

 tion between combustion, light, and living things, because in a later 

 section ^ entitled, " Experiment solitary touching wood shining in 

 the dark," Bacon described sixteen trials with this material, which 

 are quoted in Chapter XIV on Shining Wood, Fish and Flesh. He 

 also explained his reason for the inquiry: 



The experiment of wood that shineth in the dark, we have diligently 

 driven and pursued; the rather, for that of all things that give light 

 here below, it is the most durable, and hath least apparent motion. Fire 

 and flame are in continual expense; sugar shineth only while it is in 

 scraping; and salt-water while it is in dashing; glow-worms have their 

 shining while they live, or a little after; only scales of fishes putrified 



^ In Latin, pulmo marinus, in Greek, pneumon thallasios, a medusa or jellyfish, 

 many of which are luminous. Bacon appears to have suggested that jellyfish come from 

 sea foam. Since jellyfish are luminous and the sea is often luminous when it foams 

 or is agitated, the two were associated. 



^ " The New Instrument." Second book. Aphorisms. Sec. 12. 



•' Century IV, Sec. 352. 



