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sound is heard, although the flame follows after. from its nearness, doth also somewhat illustrate Both light and sound undergo the subtlest dis- the air behind the screen. But a sound excited tinctions; as sounds in words articulate, and on one side of a wall is heard on the other side light in the images of all visible objects. Light not much weaker. Sound also is heard within and sound produce, or generate almost nothing, the septa of solid bodies, though fainter, as in the except in the senses and spirits of animals. Light case of sounds within bloodstones ; or when and sound are easily generated, and soon fade bodies are struck under water. But light is not away. For there is no cause why any one should at all visible in a solid, opaque body, which is conceive that the sound, which continues for close on all sides. some time after a bell or chord has been struck, Light penetrates deeper than sound, as at the is produced at the moment of percussion; because, bottom of waters. Every sound is produced in if you touch the bell or chord, the sound instantly the motion and manifest collision of bodies: not ceases, from which it is evident, that the continu- so light. ance of the sound is created by succession. One But hostilities of light, or privations, if any like light is destroyed by a greater, as one sound by a the term better, occur not. However, as is exgreater, &c. But light and sound differ, in that ceedingly probable, the torpor of bodies, in their light, as observed, is more rapid than sound, and parts, is very inimical to light. For almost goes over larger spaces: whether or not light is nothing gives light that is not in its own nature conveyed in the body of the air, in the same man- remarkably mobile, or excited by heat, or motion, ner as sound, is uncertain: light proceeds in or vital spirit. straight lines only, but sound in crooked lines, Yet I always mean, that not only other instances and in all directions. For where any thing is remain to be investigated, (for these few we have discerned in the shadow of a screen, there is no adduced only by way of example,) but also that cause to think that the light penetrates the screen, new topical articles, as the nature of things but only that it illuminates the air around, which, requires, may be added.

FRANCIS BACON'S APHORISMS

AND

ADVICES CONCERNING THE HELPS OF THE MIND AND THE KINDLING OF

NATURAL LIGHT.

Man, the servant and interpreter of nature, does him, who can induce an effect upon certain suband understands as much as he has actually or stances only of such as are susceptible, is likementally observed of the order of nature: he wise imperfect. neither knows nor can do more.

He who knows the causes of any nature in The naked hand of man, however strong and some subjects only, knows the efficient or mateconstant, suffices for but few operations, and those riate cause, which causes are inconstant, and easy; the same, by help of instruments, performs nothing else but vehicles and causes conveying many and obstinate operations: so is it also with form. But he who comprehends the unity of the mind.

nature in the most dissimilar substances, knows The instruments of the hand excite or direct the form of things. motion: and the instruments of the mind prompt He who knows the efficient and materiate or caution the intellect.

causes, composes or divides things previously Ona given basis of matter to impose any nature, invented, or transfers and produces them; also in within the limits of possibility, is the intention of matter somewhat similar, he attaineth unto new human power.

In like manner, to know the inventions; the more deeply fixed limits of things causes of a given effect, in whatever subject, is he moveth not. the intention of human knowledge: which inten- He who knows the forms, discloses and educes tions coincide. For that which is in contempla- things which have not hitherto been done, such tion as a cause, is in operation as a medium. as neither the vicissitudes of nature, nor the dili

The knowledge of him who knows the cause gence of experience might ever have brought into of any nature, as of whiteness or of heat, in certain action, or as might not have entered into man's subjects only, is imperfect. And the power of thought

The same is the way and the perfection of truth | light belongs not to the form of heat, it is the and of power: this, namely, to discover the forms same as if you were to say, in producing heat it of things, from the knowledge of which followeth is not necessary to produce light also. true contemplation and free operation.

(The rest were not finished.) The discovery of forms which proceeds by the Nor do these proceed under our authority. Lexclusion or rejection of natures is simple and one. Thou, O Father, turning to the works which thy For all natures, which are absent in a given pre- hands made, saw that all things were very good; sent nature, or present in a given absent nature, but man, turning to the works which his hands pertain not to form; and, after complete rejection made, saw that all was vanity and vexation or negation, the form and affirmation remains. If of spirit. Therefore, if we have laboured amid you inquire, for example, into the form of heat, thy works, thou wilt make us partakers of thy and find water hot, yet not lucid, reject light: if gratulation and of thy Sabbath. We humbly you find air thin, yet not hot, reject tenuity. entreat that this disposition may abide in us; and This is short to say, but it is reached by a long that by our hands the human family may be circuit.

These we The contemplative and the operative utterance commend to thy eternal love, through our Jesus, of words differ not in reality. For when you say, thy Christ, God with us.