454 APHORISMS. sound is heard, although the flame follows after. Both light and sound undergo the subtlest dis tinctions ; as sounds in words articulate, and light in the images of all visible objects. Light and sound produce, or generate almost nothing, except in the senses and spirits of animals. Light and sound are easily generated, and soon fade away. For there is no cause why any one should conceive that the sound, which continues for some time after a bell or chord has been struck, is produced at the moment of percussion ; because, if you touch the bell or chord, the sound instantly ceases, from which it is evident, that the continu ance of the sound is created by succession. One light is destroyed by a greater, as one sound by a greater, &c. But light and sound differ, in that light, as observed, is more rapid than sound, and goes over larger spaces : whether or not light is conveyed in the body of the air, in the same man ner as sound, is uncertain: light proceeds in straight lines only, but sound in crooked lines, and in all directions. For where any thing is discerned in the shadow of a screen, there is no cause to think that the light penetrates the screen, but only that it illuminates the air around, which, from its nearness, doth also somewhat illustrate the air behind the screen. But a sound excited on one side of a wall is heard on the other side not much weaker. Sound also is heard within the septa of solid bodies, though fainter, as in the case of sounds within bloodstones ; or when bodies are struck under water. But light is not at all visible in a solid, opaque body, which is close on all sides. Light penetrates deeper than sound, as at the bottom of waters. Every sound is produced in the motion and manifest collision of bodies : not so light. But hostilities of light, or privations, if any like the term better, occur not. However, as is ex ceedingly probable, the torpor of bodies, in their parts, is very inimical lo light. For almost nothing gives light that is not in its own nature remarkably mobile, or excited by heat, or motion, or vital spirit. Yet I always mean, that not only other instances remain to be investigated, (for these few we have adduced only by way of example,) but also that new topical articles, as the nature of things requires, may be added. FRANCIS BACON S APHORISMS ADVICES CONCERNING THE HELPS OF THE MIND AND THE KINDLING OF NATURAL LIGHT. MAN, the servant and interpreter of nature, does and understands as much as he has actually or mentally observed of the order of nature: he neither Knows nor can do more. The naked hand of man, however strong and constant, suffices for but few operations, and those easy ; the same, by help of instruments, performs many and obstinate operations : so is it also with the mind. The instruments of the hand excite or direct motion : and the instruments of the mind prompt or caution the intellect. On a giver? basis of matter to impose any nature, within the limits of possibility, is the intention of human power. In like manner, to know the causes of a given effect, in whatever subject, is the intention of human knowledge: which inten tions coincide. For that which is in contempla tion as a cause, is in operation as a medium. The knowledge of him who knows the cause of any nature, as of whiteness or of heat, in certain subjects only, is imperfect. And the power of him, who can induce an effect upon certain sub stances only of such as are susceptible, is like wise imperfect. He who knows the causes of any nature in some subjects only, knows the efficient or mate- riate cause, which causes are inconstant, and nothing else but vehicles and causes conveying form. But he who comprehends the unity of nature in the most dissimilar substances, knows the form of things. He who knows the efficient and materiate causes, composes or divides things previously invented, or transfers and produces them; also in matter somewhat similar, he attaineth unto new inventions ; the more deeply fixed limits of things he moveth not. He who knows the forms, discloses and educes things which have not hitherto been done, such as neither the vicissitudes of nature, nor the dili gence of experience might ever have brought into action, or as might not have entered into man s thoughts.
