it be an opaque body, may yet reflect light by | light at all were present. Thus the visible body reason of its magnitude. We must ascertain, too, whether or not the aggregation of lucid bodies multiplies light. And in regard to bodies equally lucid there is no doubt of this but it remains for inquiry, whether or not a light, which is evidently overcome and rendered of itself invisible by a greater light, doth not yet add some light. Whatsoever is bright also contributes somewhat of light, for an apartment is much lighter when hung with silk than with cloth. Light is also multiplied by refraction; for gems when cut into angles, and glass when broken, shine much more than if they were smooth. VII. Modes of destroying Light. The modes of destroying light must also be remarked as by the exuberance of greater light, and by dense and opaque mediums. The sun's rays certainly, falling on the flame of a fire, make the flame seem like a kind of whiter smoke. VIII. Operations or Effects of Light. We have to consider the operations or effects of light, which, it seems, are few, and possess little power of changing bodies, especially solids. Light above all things generates itself, other qualities sparingly. Light doth certainly in some measure attenuate the air, is grateful to the spirits of animals, and exhilirates them; it excites the slumbering rays of all colours and visible things for every colour is the broken image of light IX. Continuance of Light. The continuance of light must be investigated; which, as it appears, is momentary. For light doth not illuminate an apartment more when it hath continued there for many hours, than for any single moment; which is not so in respect of heat, &c.; for the first portion of heat remains, and a new one is added to it. Yet, twilight is by some thought to arise from the traces of the sun. X. Ways and Progress of Lagnt. We have attentively to consider the ways and progress of light. Light is shed around on all sides; but it remains for inquiry whether it at the same time ascends a little, or is equally shed around, upwards, and downwards. The light itself generates light everywhere around it; so that when the body of light, on interposing a screen, is not discerned, yet the light itself illuminates every thing around, except the objects which fall within the shadow of the screen: these, however, receive some light from the light which is thrown around; for any thing within the shadow of the screen can be discerned much better than if no of any lucid object, and the light itself, seem to be things different. Light doth not penetrate bodies which are fibrous and of unequal structure; but yet is not impeded by the solid hardness of a substance, as you shall see in glass and the like. Thus the straight line and the pores which are not transverse, alone seem to transmit light. The best conductor of light is air, which conveys light the better the purer it is. It remains for inquiry whether or not light is carried through the body of the air. Sounds certainly we see carried by winds, so that they may be heard farther when going with the wind than against it. But it remains for inquiry whether or not any thing of the kind takes place with light. XI. Transparency of Lucid Bodies. We must also inquire respecting the transparency of lucid bodies. The wick of a candle is seen within the flame; but through larger flames objects reach not the sight. But again, all transparency is lost on heating any body, as may be seen in glass, which is no longer transparent when heated. The substance of air is transparent, also of water; yet, these two transparent substances when mixed, as in snow or foam, are no longer transparent, but acquire a certain light of their own. XII. Cognations and Hostilities of Light. must be investigated. Light, as far as regards The cognations, and also the hostilities of light its production, has most of all cognation with three things, heat, tenuity, and motion. We must, these three with light, also the degrees of these therefore, consider the marriages and divorces of of wine or of an ignis fatuus, has a much feebler same marriages and divorces. The flame of spirit heat than red-hot iron, but a stronger light. Glowworms, and the dews of salt water, and many of the things which we mentioned, throw burning metals are not subtile bodies, but yet they out light, yet are not hot to the touch. have an ardent heat. But, on the other hand, air is one of the subtlest bodies, yet it is void of light; again, this same air, and also winds, though rapid in motion, afford no light. But, on the other hand, burning metals do not lay aside their sluggish motion, nevertheless vibrate light. Also But in the cognations of light, which have no relation to its production, but only to its progression, nothing is so much allied to it as sound. To the sympathies and disagreements of the two we must therefore strictly direct our attention. In the following they agree: both light and sound are diffused around on all sides. Light and sound are conveyed through very large spaces; but light more swiftly, as we see in can nons, where the light is sooner discerned than the But a sound excited on one side of a wall is heard on the other side Sound also is heard within not much weaker. the septa of solid bodies, though fainter, as in the case of sounds within bloodstones; or when But light is not bodies are struck under water. 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 sound is heard, although the flame follows after. | from its nearness, doth also somewhat illustra Both light and sound undergo the subtlest dis- the air behind the screen. 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- | so light. 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 manner 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, But hostilities of light, or privations, if any like the term better, occur not. However, as is exceedingly probable, the torpor of bodies, in their For almost parts, is very inimical to light. 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 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. 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 given 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 intentions coincide. For that which is in contemplation 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 He who knows the causes of any nature in some subjects only, knows the efficient or materiate 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 diligence of experience might ever have brought into action, or as might not have entered into man's thoughts. 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 discovery of forms which proceeds by the exclusion or rejection of natures is simple and one. For all natures, which are absent in a given present nature, or present in a given absent nature, pertain not to form; and, after complete rejection or negation, the form and affirmation remains. If you inquire, for example, into the form of heat, and find water hot, yet not lucid, reject light: if you find air thin, yet not hot, reject tenuity. This is short to say, but it is reached by a long circuit. (The rest were not finished.) Nor do these proceed under our authority. Thou, O Father, turning to the works which thy hands made, saw that all things were very good; but man, turning to the works which his hands made, saw that all was vanity and vexation of spirit. Therefore, if we have laboured amid thy works, thou wilt make us partakers of thy We humbly gratulation and of thy Sabbath. entreat that this disposition may abide in us; and that by our hands the human family may be endowed with new alms from thee. These we The contemplative and the operative utterance commend to thy eternal love, through our Jesus, J. A. C. of words differ not in reality. For when you say, thy Christ, God with us. THE END OF VOL. I. |