Part 8

I perceive you are not fully satisfied with my former Letter concerning Eccho, and a figure presented in a Looking-glass; for you say, how is it possible, if Eccho consists in the ears patterning out of a voice or sound, but that it will make a confusion in all the parts of the air? My answer is, that I doe not say that Eccho is onely made by the patterning out of the voice or sound, but by repeating the same voice or sound, which repetition is named an Eccho, for millions of ears in animals may pattern out a voice or words, and yet never repeat them, and so may millions of parts of the air; wherefore Eccho doth not consist in the bare patterning out, but in the repetition of the same sound or words, which are pattern'd out; and so some parts of the air may at one and the same time pattern out a sound and not repeat it, and some may both pattern out, and repeat it, but some may neither pattern out, nor repeat it, and therefore the Repetition, not the bare Patterning out is called Eccho: Just as when two or more men do answer or mock each other, and repeat each others words, it is not necessary, if there were a thousand standers by, that they should all do the same. And as for the figure presented in a Looking-glass, I cannot conceive it to be made by pressure and reaction; for although there is both pressure and reaction in nature, and those very frequent amongst natures Parts, yet they do neither make perception nor production, although both pressure and reaction are made by corporeal self-motions; Wherefore the figure presented in a Looking-glass, or any other smooth glassie body, is, in my opinion, onely made by the motions of the Looking-glass, which do both pattern out, and present the figure of an external object in the Glass: But you will say, why do not the motions of other bodies pattern out, and present the figures of external objects, as well as smooth glassie bodies do? I answer, they may pattern out external objects, for any thing I know; but the reason that their figures are not presented to our eyes, lies partly in the presenting subject it self, partly in our sight; for it is observed, that two things are chiefly required in a subject that will present the figure of an external object; first it must be smooth, even and glassie, next it must not be transparent: the first is manifest by experience; for the subject being rough and uneven, will never be able to present such a figure; as for example, A piece of steel rough and unpolished, although it may perhaps pattern out the figure of an external object, yet it will never present its figure, but as soon as it is polished, and made smooth and glassie, the figure is presently perceived. But this is to be observed, that smooth and glassie bodies do not always pattern out exterior objects exactly, but some better, some worse; like as Painters have not all the same ingenuity; neither do all eyes pattern out all objects exactly; which proves that the perception of sight is not made by pressure and reaction, otherwise there would be no difference, but all eyes would see alike. Next I say, it is observed, that the subject which will present the figure of an external object, must not be transparent; the reason is, that the figure of Light being a substance of a piercing and penetrating quality, hath more force on transparent, then on other solid dark bodies, and so disturbs the figure of an external object pattern'd out in a transparent body, and quite over-masters it. But you will say, you have found by experience, that if you hold a burning Candle before a Transparent-glass, although it be in an open Sun-light, yet the figure of light and flame of the Candle will clearly be seen in the Glass. I answer, that it is an other thing with the figure of Candle-light, then of a duskish or dark body; for a Candle-light, though it is not of the same sort as the Suns light, yet it is of the same nature and quality, and therefore the Candle-light doth resist and oppose the light of the Sun, so that it cannot have so much power over it, as over the figures of other bodies patterned out and presented in Transparent-glass. Lastly, I say, that the fault oftentimes lies in the perceptive motions of our sight, which is evident by a plain and Concave-glass; for in a plain Looking-glass, the further you go from it, the more your figure presented in the glass seems to draw backward; and in a Concave-glass, the nearer you go to it, the more seems your figure to come forth: which effects are like as an house or tree appears to a Traveller; for, as the man moves from the house or tree, so the house or tree seems to move from the man; or like one that sails upon a Ship, who imagines that the Ship stands still, and the Land moves; when as yet it is the Man and the Ship that moves, and not the House, or Tree, or the Land; so when a Man turns round in a quick motion, or when his head is dizzie, he imagines the room or place, where he is, turns round. Wherefore it is the Inherent Perceptive motions in the Eye, and not the motions in the Looking-glass, which cause these effects. And as for several figures that are presented in one glass, it is absurd to imagine that so many several figures made by so many several motions should touch the eye; certainly this would make such a disturbance, if all figures were to enter or but to touch the eye, as the eye would not perceive any of them, at lead not distinctly; Wherefore it is most probable that the glass patterns out those figures, and the sensitive corporeal motions in the eye take again a pattern from those figures patterned out by the glass, and so make copies of copies; but the reason why several figures are presented in one glass in several places, is, that two perfect figures cannot be in one point, nor made by one motion, but by several corporeal motions. Concerning a Looking-glass, made in the form or shape of a Cylinder, why it represents the figure of an external object in an other shape and posture then the object is, the cause is the shape and form of the Glass, and not the patterning motions in the Glass. But this discourse belongs properly to the Opticks, wherefore I will leave it to those that are versed in that Art, to enquire and search more after the rational truth thereof. In the mean time, my opinion is, that though the object is the occasion of the figure presented in a Looking-glass, yet the figure is made by the motions of the glass or body that presents it, and that the figure of the glass perhaps may be patterned out as much by the motions of the object in its own substance, as the figure of the object is patterned out and presented by the motions of the glass in its own body or substance. And thus I conclude and rest,

Madam,

_Your Faithful Friend_

_and Servant._

XXVI.

_MADAM,_

Since I mentioned in my last that Light did disturb the figures of External objects presented in Transparent bodies; you were pleased to ask, Whether light doth penetrate transparent bodies? I answer, for anything I know, it may; for when I consider the subtil, piercing and penetrating nature of light, I believe it doth; but again, when I consider that light is presented to our sight by transparent bodies onely, and not by duskish and dark bodies, and yet that those duskish bodies are more porous then the transparent bodies, so that the light hath more passage to pass through them, then through transparent bodies; but that on the contrary, those dark bodies, as Wood, and the like, do quite obscure the light, when as transparent bodies, as Glass, &c. transmit it, I am half perswaded that the transparent bodies, as Glass, rather present the Light by patterning it out, then by giving it passage: Also I am of a mind, that the air in a room may pattern out the Light from the Glass, for the Light in a room doth not appear so clear as in the Glass; also if the Glass be any way defective, it doth not present the Light so perfectly, whereas, if it were the penetration of light through the glass, the light would pass through all sorts of glass alike, which it doth not, but is more clearly seen through some, and more obscurely through others, according to the goodness or purity of the glass. But you may say, that the light divulges the imperfection or goodness of the glass; I answer, so it doth of any other objects perceived by our sight; for light is the presenter of objects to the sense and perception of sight, and for any thing I know, the corporeal optick motions make the figure of light, the ground figure of all other figures patterned out by the corporeal optick motions, as in dreams, or when as some do see in the dark, that is, without the help of exterior light. But you may say, That if the glass and the air in a room did pattern out the figure of light, those patterns of light would remain when light is absent: I answer, That is not usual in nature; for when the object removes, the Pattern alters; I will not say but that the corporeal optick motions may work by rote without objects, but that is irregular, as in some distempers. And thus, _Madam_, I have given you my opinion also to this your question; if you have any more scruples, I pray let me know of them, and assure your self that I shall be ready upon all occasions to express my self,

Madam,

_Your humble and faithful Servant._

XXVII.

_MADAM,_

Your desire is to know, why sound is louder in a Vault, and in a large Room then in a less? I answer, A Vault or arched Figure is the freest from obstruction, as being without corners and points, so as the sensitive and rational corporeal motions of the Ear can have a better perception; like as the Eye can see farthest from a hill then being upon a level ground, because the prospect is freer from the hill, as without obstruction, unless it be so cloudy that the clouds do hinder the perception; And as the eye can have a better prospect upon a hill, so the ear a stronger perception in a Vault; And as for sound, that it is better perceived in a large, then in a little close room or place, it is somewhat like the perception of sent, for the more the odorous parts are bruised, the stronger is that perception of sent, as being repeated double or treble, which makes the perception stronger, like as a thick body is stronger then a thin one; So likewise the perception of sound in the air; for though not all the parts of the air make repetitions, yet some or many make patterns of the sound; the truth is, Air is as industrious to divulge or present a sound, by patterns to the Ear, as light doth objects to the Eye. But then you may ask me, Why a long hollow pipe doth convey a voice to the ear more readily, then any large and open place? My answer is, That the Parts of the air in a long pipe are more Composed and not at liberty to wander, so that upon necessity they must move onely to the patterning out of the sound, having no choice, which makes the sound much stronger, and the perception of the Ear perfecter; But as for Pipes, Vaults, Prospects, as also figures presented in a room through a little hole, inverted, and many the like, belongs more to Artists then to my study, for though Natural Philosophy gives or points out the Ground, and shews the reason, yet it is the Artist that Works; Besides it is more proper for Mathematicians to discourse of, which study I am not versed in; and so leaving it to them, I rest,

Madam,

_Your faithful Friend_

_and Servant._

XXVIII.

_MADAM,_

From Sound I am come to Sent, in the discourse whereof, your _Author_[1] is pleased to set down these following propositions: 1. _That smelling is hindred by cold and helped by heat_: 2. _That when the Wind bloweth from the object, the smell is the stronger, and when it blows from the sentient towards the object, the weaker, which by experience is found in dogs, that follow the track of beasts by the Sent_: 3. _That such bodies as are last pervious to the fluid medium, yield less smell then such as are more pervious_: 4. _That such bodies as are of their own nature odorous, become yet more odorous, when they are bruised_: 5. _That when the breath is stopped (at least in man) nothing can be smelt_: 6. _That the Sense of smelling is also taken away by the stopping of the nostrils, though the mouth be left open._ To begin from the last, I say, that the nose is like the other sensitive organs, which if they be stopt, the corporeal sensitive motions cannot take copies of the exterior objects, and therefore must alter their action of patterning to some other, for when the eye is shut and cannot perceive outward objects then it works to the Sense of Touch, or on the inside of the organ to some phantasmes; and so do the rest of the Senses. As for the stopping of breath, why it hinders the Sent, the cause is, that the nostrils and the mouth are the chief organs, to receive air and to let out breath: but though they be common passages for air and breath, yet taste is onely made in the mouth and tongue, and sent in the nose; not by the pressure of meat, and the odoriferous object, but by patterning out the several figures or objects of sent and taste, for the nose and the mouth will smell and taste one, nay several things at the same time, like as the eye will see light, colour, and other objects at once, which I think can hardly be done by pressures; and the reason is, that the sensitive motions in the sensitive organs make patterns of several objects at one time, which is the cause, that when flowers, and such like odoriferous bodies are bruised, there are as many figures made as there are parts bruised or divided, and by reason of so many figures the sensitive knowledg is stronger; but that stones, minerals, and the like, seem not so strong to our smell, the reason is, that their parts being close and united, the sensitive motions in the organ cannot so readily perceive and pattern them out, as those bodies which are more porous and divided. But as for the wind blowing the sent either to or from the sentient, it is like a window or door that by the motion of opening and shutting, hinders or disturbeth the sight; for bodies coming between the object and the organ, make a stop of that perception. And as for the Dogs smelling out the track of Beasts, the cause is, that the earth or ground hath taken a copy of that sent, which copy the sensitive motions in the nose of the Dog do pattern out, and so long as that figure or copy lasts, the Dog perceives the sent, but if he doth not follow or hunt readily, then there is either no perfect copy made by the ground, or otherwise he cannot find it, which causes him to seek and smell about until he hath it; and thus smell is not made by the motion of the air, but by the figuring motions in the nose: Where it is also to be observed, that not onely the motions in one, but in millions of noses, may pattern out one little object at one time, and therefore it is not, that the object of sent fills a room by sending out the sent from its substance, but that so many figures are made of that object of sent by so many several sensitive motions, which pattern the same out; and so the air, or ground, or any other creature, whose sensitive motions pattern out the object of sent, may perceive the same, although their sensitive organs are not like to those of animal Creatures; for if there be but such sensitive motions and perceptions, it is no matter for such organs. Lastly, it is to be observed, That all Creatures have not the same strength of smelling, but some smell stronger, some weaker, according to the disposition of their sensitive motions: Also there be other parts in the body, which pattern out the object of sent, besides the nose, but those are interior parts, and take their patterns from the nose as the organ properly designed for it; neither is their resentment the same, because their motions are not alike, for the stomack may perceive and pattern out a sent with aversion, when the nose may pattern it out with pleasure. And thus much also of Sent; I conclude and rest,

Madam,

_Your faithful Friend,_

_and Servant._

[1] _Ch._ 29. _art._ 12.

XXIX.

_MADAM,_

Concerning your Learned Authors discourse of Density and Rarity, he defines[1] _Thick to be that, which takes up more parts of a space given; and thin, which containes fewer parts of the same magnitude: not that there is more matter in one place then in an other equal place, but a greater quantity of some named body; wherefore the multitude and paucity of the parts contained within the same space do constitute density and rarity._ Whereof my opinion is, That there is no more nor less space or place then body according to its dilation or contraction, and that space and place are dilated and contracted with the body, according to the magnitude of the body, for body, place and magnitude are the same thing, only place is in regard of the several parts of the body, and there is as well space betwixt things distant a hairs breadth from one another, as betwixt things distant a million of miles, but yet this space is nothing from the body; but it makes, that that body has not the same place with this body, that is, that this body is not that body, and that this bodies place is not that bodies place. Next your _Author_ sayes,[2] _He hath already clearly enough demonstrated, that there can be no beginning of motion, but from an external and moved body, and that heavy bodies being once cast upwards cannot be cast down again, but by external motion._ Truly, _Madam_, I will not speak of your _Authors_ demonstrations, for it is done most by art, which I have no knowledg in, but I think I have probably declared, that all the actions of nature are not forced by one part, driving, pressing, or shoving another, as a man doth a wheel-barrow, or a whip a horse; nor by reactions, as if men were at foot-ball or cuffs, or as men with carts meeting each other in a narrow lane. But to prove there is no self-motion in nature, he goes on and says; _To attribute to created bodies the power to move themselves, what is it else, then to say that there be creatures which have no dependance upon the Creator?_ To which I answer, That if man (who is but a single part of nature) hath given him by God the power and a free will of moving himself, why should not God give it to Nature? Neither can I see, how it can take off the dependance upon God, more then Eternity; for, if there be an Eternal Creator, there is also an Eternal Creature, and if an Eternal Master, an Eternal Servant, which is Nature; and yet Nature is subject to Gods Command, and depends upon him; and if all Gods Attributes be Infinite, then his Bounty is Infinite also, which cannot be exercised but by an Infinite Gift, but a Gift doth not cause a less dependance. I do not say, That man hath an absolute Free-will, or power to move, according to his desire; for it is not conceived, that a part can have an absolute power: nevertheless his motion both of body and mind is a free and self-motion, and such a self-motion hath every thing in Nature according to its figure or shape; for motion and figure, being inherent in matter, matter moves figuratively. Yet do I not say, That there is no hindrance, obstruction and opposition in nature; but as there is no particular Creature, that hath an absolute power of self-moving; so that Creature which hath the advantage of strength, subtilty, or policy, shape, or figure, and the like, may oppose and over-power another which is inferior to it, in all this; yet this hinderance and opposition doth not take away self-motion. But I perceive your _Author_ is much for necessitation, and against free-will, which I leave to Moral Philosophers and Divines. And as for the ascending of light, and descending of heavy bodies, there may be many causes, but these four are perceiveable by our senses, as bulk, or quantity of body, grossness of substance, density, and shape or figure, which make heavy bodies descend: But little quantity, purity of substance, rarity, and figure or shape make light bodies ascend. Wherefore I cannot believe, that there are[3] _certain little bodies as atoms, and by reason of their smallness, invisible, differing from one another in consistence, figure, motion and magnitude, intermingled with the air_, which should be the cause of the descending of heavy bodies. And concerning air,[4] _whether it be subject to our senses or not_, I say, that if air be neither hot, nor cold, it is not subject; but if it be, the sensitive motions will soon pattern it out, and declare it. I'le conclude with your _Authors_ question,[5] _What the cause is, that a man doth not feel the weight of Water in Water?_ and answer, it is the dilating nature of Water. But of this question and of Water I shall treat more fully hereafter, and so I rest,

Madam,

_Your faithful Friend_

_and Servant._

[1] _C._ 30. _a._ 1.

[2] _Art._ 2.

[3] _Art._ 3.

[4] _Art._ 14.

[5] _Art._ 6.

XXX.

_MADAM,_