Sylva Sylvarum (1631 English edition)

...grows. And regarding use, his Lordship often mentions the two kinds of experiments: fruit-bearing experiments original: Experimenta Fructifera and light-bearing experiments original: Experimenta Lucifera—that is, experiments of use and experiments of light. And he asks himself whether he would not be a strange man to think that light has no use just because it has no physical substance.

Furthermore, his Lordship also thought it good to add to many of the experiments themselves some explanation original: glosse; an interpretive note or commentary of their causes, so that in the succeeding work of interpreting nature and framing axioms general principles or laws of nature, everything may be more prepared. As for the causes assigned here, his Lordship is persuaded that they are far more certain than those provided by others—not because of any excellence in his own intelligence (as his Lordship is accustomed to say), but because of his continual interaction with nature and experience.

He also considered that by adding these causes, men's minds (which are so hasty to find out the causes of things) would not think themselves utterly lost in a vast forest of experience. Instead, they might rest upon these causes (such as they are) for a little while, until true axioms can be more fully discovered. I have also heard his Lordship say that one great reason why he would not put these details into any exact method (though anyone who looks attentively at them will find they have a secret...