The firſt Letter to Monſieur des Cartes.

SIR, I ſhould have been very glad to have ſeen you this laſt Summer at Paris, becauſe I thought you would have come thither on purpoſe to ſtay there, and that having more con­veniences there then any where elſe to try expe­riments, whereof you have intimated you ſtand in need to finiſh the Treatiſes you promiſed to the world, you would not fail to keep your word with me, and wee ſhould ſhortly ſee them prin­ted; but you have utterly defeated me of that joy, by your return to Holland: and I cannot here refrain from telling you, that I am angry with you, for not letting me (before you took your journey) ſee the Treatiſe of the Paſſions, which, I was told, you had compiled. Beſides, reflecting on ſome words I had read in a Pre­face ſome two years ſince uſhering the tranſla­tion of your Principles into French, wherein af­ter you had ſpoken ſuccinctly of the parts of Philoſophy yet to be diſcovered, before the chief fruit thereof can be gathered, and ſaid, that you do not ſo much miſtruſt your own ſtrength, but you dare undertake to make them all known if you had conveniences to try experiments to maintain, and juſtifie your arguments, you adde, greater expences are neceſſary for that purpoſe, than a private man, as you are, is able to diſ­burſe unleſs aſſiſted by the publique: but that ſince you could not expect this aſſiſtance, you thought to reſt contented from thence forwards with ſtudying for your own private inſtruction; and that poſterity ſhould excuſe you, if you left off labouring for them: now I am afraid in good earneſt that you will envy the world the reſt of your inventions, and wee never ſhall have any thing elſe of you, if we let you follow your own inclination. This is the reaſon why I bethought me to torment you a little with this Letter, and revenge my ſelf of your refuſall of that Treatiſe of the Paſſions to me, by ingenuouſ­ly reproving you for lazineſſe and other faults, which, I conceive, hinder you from improving your talent, as you may, and your duty binds you. Upon my word, I cannot think it any thing but your lazineſſe, and little care to be ſerviceable to mankind, which cauſeth you not to go forwards with your Phyſicks: for though I very well underſtand, it is impoſſible for you to finiſh them without many experiments, which ought to be defrayed by the publique, becauſe they will reap the profit of it, and a private mans eſtate is not ſufficient to do it; yet I do not be­lieve that is your Remora, for you cannot chooſe but obtain from the diſpencers of the publique treaſure, all you can wiſh to that purpoſe, if you would but vouchſafe to make known to them how the caſe ſtands, as you eaſily might do, had you a will to it; but you have ever lived in a way ſo repugnant thereunto, that there is reaſon to ſuſpect that you would not accept aſſiſtance from any one, though it were offered to you; and yet you pretend, poſterity ſhall excuſe you, if you take pains for it no more, on a ſuppoſition that this aſſiſtance is neceſſary, and you cannot get it; which gives me occaſion to think, not on­ly that you are too ſparing of your pains, but, it may be, that you have not courage enough to hope to goe through with what they who have read your writings expect of you; and yet you are ſo vainglorious as to perſwade our ſucceſſors, that you failed not of it by any fault of your own, but becauſe your vertue was not encouraged as it ought to have been, and you were denyed furtherance in your deſignes; wherein, I ſee, your ambition hits the mark it aimed at becauſe they who hereafter ſhall view your works, will conceive by what you publi­ſhed a dozen years agoe, that you then had found out all that ſince hath been ſeen to come from you, and what remains to be inveſtigated in Phyſicks, is leſſe difficult then what you have already made known: ſo that you might ſince have given us all that may be expected from humane reaſon concerning Phyſick, and other neceſſaries of life, if you had had conveniences to make experiments requiſite thereunto: nay, that you have found out a good part of them too, but a juſt indignation againſt the ingrati­tude of man hath diſſwaded you from letting them participate of your inventions; ſo you think that by lying ſtill for ever, you ſhall ac­quire as much reputation, as if you took pains for it; and, if may be, more, becauſe common­ly good poſſeſſed, is more valued then what is deſired, or lamented. But I'l debar you from getting reputation without deſerving it; and though I doubt not but you knew well enough what you ſhould have done, if you would have been helped by the publique: for indeed, I will cauſe this Letter to be printed, that you may not pretend ignorance of it; that if here­after you fail to ſatisfie us, you may no more impute it to this age; for know, it is not enough to obtaine any thing from the publike, to have blurted out an occaſionall word of it in the Preface of a book, not abſolutely ſaying that you deſire it, and expect it, nor giving them proofes not only that you deſerve it, but that they ought for their own ſakes to grant it you, in regard they expect great profit by it; It is uſu­ally ſeen, that they, who think they have any thing in them, make ſuch a noiſe of it, and ſo importunately demand what they pretend to, and promiſe ſo farre beyond what they can perform, that when a man only ſpeaks modeſt­ly of himſelf, and requires nought from any man, nor promiſes any thing certainly, what proofe ſoever hee gives otherwiſe of his ſuf­ficiencie, hee is neither lookt nor thought on.

You'l ſay, it may bee, that it goes againſt your nature to requeſt any thing, or ſpeak advantagiouſly of your ſelf; becauſe, one ſeems a mark of a mean ſpirit, the other of Pride. But, ſay I, this humour is to be corrected, for it proceeds from an errour of weakneſs, rather then a becomming ſhamefacedneſs and mode­ſty; for, for matter of requeſts, a man hath no reaſon to be aſhamed of any, unleſſe ſuch as hee makes meerly for his own peculiar be­nefit, to thoſe from whom in juſtice hee ought not to exact any. So far ſhould hee be, from being of thoſe that tend to the publique utilitie and profit of them to whom they are made, that on the contrary hee may extract glo­ry from them, eſpecially when hee hath already beſtowed things on them worth much more than hee would obtain of them; and for ſpeaking advantagiouſly of a mans ſelfe, it is true, it is a moſt ridiculous, and blame­able pride, when hee ſpeakes falſe things of himſelfe; and it is even a contemp­tible vanity too, when he ſpeaks only truths, meerly out of oſtentation, and ſo that no good accrew to any one thereby; but when theſe things ſo much concern other men to know, it is moſt certain they cannot be concealed, but out of a vicious humility, which is a ſort of baſeneſs, and weakneſs. Now, it highly con­cerns the publique to be advertiſed of what you have gathered in Sciences, that thereby judging what you are able to diſcover in them further, it may be incited to contribute its utmoſt to help you therein, as in a work whoſe end is the generall good of mankind, and the things you have already given, the important truths, you have laid down in your Books, are worth in­comparably much more than any thing you can ask for this purpoſe.

You may alſo ſay that your works ſpeak enough, and there is no need of adding promiſes and brags, which being the merchandize of jug­gling Mountebanks ſeem not becomming a man of honour, who only ſearcheth after truth: but Mountebanks are not blame-worthy for talking high and well of themſelves, but for ſpeaking untruths, and things they cannot make good; whereas thoſe which (I urge) you ſhould ſpeak of your ſelf, are ſo true, and ſo manifeſtly pro­ved in your writings, that the ſtricteſt rules of modeſty give you leave to aſcertain them, and thoſe of Charity oblige you thereunto, becauſe it concerns others to know it. For although your writings ſay enough to thoſe who exa­mine them throughly, and are able to under­ſtand them; yet that is not ſufficient for the deſigne I would adviſe you to, becauſe every one is not able to read them, and they who manage the publique affaires can ſcarce have any leiſure to doe it. It may be, ſome who have read them, tell them of it: but whatſoever a man ſay to them of it, the little coile, they know, you keep, and the too great modeſty you have ever obſerved in ſpeaking of your ſelf, make them not take any great notice thereof. And indeed becauſe it a uſuall thing a­mong them to beſtow the higheſt tearms imaginable on the commendation of very in­different men, they are not apt to receive the immenſe praiſes beſtowed on you by thoſe who know you, for exact truths; whereas when any man ſpeaks of himſelf extraordinari­ly, they hearken to him with more attention, eſpecially if hee be a man of good birth, and they know him to bee neither by na­ture, nor his rank, likely to act the Mounte­bank; and becauſe hee would become ridi­culous if he ſhould uſe hyperbolies on ſuch an occaſion, his words are taken in their true ſence: and they who will not believe them are incited at leaſt by their curioſity, or jea­louſie, to examine the truth of them; where­fore it being moſt certain, and the publique being much concerned in knowing that no man in the world but your ſelfe (at leaſt whoſe writings wee have) ever diſcovered the true principles, and underſtood the firſt cauſes of whatever is produced in nature; and that ha­ving already given an account by theſe Prin­ciples, of all thoſe things which are moſt viſi­ble, and frequently obſerved in the world, you need only ſome particular obſervations to find out, in like manner, the reaſons of whatſoe­ver may be uſefull to man in this life, and ſo give us a compleat knowledge of the nature of all mineralls, the vertues of all Plants, the properties of animals, and generally all that may be beneficiall to Phyſick, or other arts. And laſtly, that theſe particular obſervations not being poſſible to bee all made in a ſmall time without great expence, all people of the earth ought emulouſly to contribute thereunto, as to the moſt important thing in the world, wherein they have all an equall intereſt. This being, I ſay, moſt certain, to bee ſufficiently proved by your works already printed, you ſhould talk ſo lowd of it, publiſh it with ſo much care, and put it ſo punctually in all the Title-pages of your Books, that none hereaf­ter might pretend ignorance. So at leaſt, you would immediately beget a longing in many to examine what the matter is: ſo that the further they enquired into it, and the more diligently they read your Books, they would the more clearly underſtand, you not unjuſtly boaſted.

And I would wiſh you chiefly to clear three things to the world. Firſt, that there are a nu­merous company of things to be found out in Phyſicks, that may bee extreamly profitable for life: Secondly, that there is great reaſon to expect the finding them out from you: And thirdly, that the more conveniences you had to make experiments, the more of them you could find out; It is neceſſary to be informed of the firſt becauſe moſt men think there can nothing be found out in the Sciences, better then what hath been found by the Ancients; and ſome conceive not ſo much as what the meaning of Phyſicks is, or what they are good for. Now it is eaſie to prove that the too great reverence born to antiquity, is an errour extreamly prejudicial to the advancement of Sciences. For it is ſeen that the ſavage people of America, and many others who inhabite places leſſe remote, have many leſſe conveniences of life then wee, and yet their originall is as ancient as ours, ſo that they have as much reaſon as wee to ſay that they are ſa­tisfied with the wiſdome of their fathers, and that they believe no man can teach them better than what hath been known and practized a­mong them from all Antiquity. And this opi­nion is ſo prejudiciall, that till it be rejected, it is impoſſible any new learning can be acqui­red: beſides, experience ſhewes, that the people whoſe mind it is deepeſt rooted in, are they who are yet moſt ignorant, and leaſt civilized; and becauſe it is frequent enough yet amongſt us, that may be one reaſon to prove, that wee are farre from knowing all wee are capable of; Which may be proved by many exceeding pro­ſitable inventions, as the uſe of the Compaſſe, the Art of Printing Perſpective glaſſes, and the like, which were not found out till theſe latter ages, although now they ſeem ve­ry eaſie to thoſe that know them. But there is nothing, wherein our neceſſity of acqui­ring new knowledge is more apparent than in Phyſick: For although no man doubts that God hath furniſhed this earth with all things neceſſary for man, to conſerve him therein in perfect health untill an extreame old age; and although there be nothing in the world ſo deſired as theſe things, ſo that heretofore it hath bin the ſtudy of Kings and Sages; yet experience ſhews, wee are ſo far from having it wholly, that of­times a man is chained to his bed by ſmall di­ſeaſes, which the moſt learned Phyſicians under­ſtand not, and onely make them rage more by their remedies, when they undertake to expell them. Wherein the defect of their art, and the neceſſity of perſecting it, is ſo evident, that for thoſe who underſtand not what the meaning of Phyſicks is, it is enough to tell them, that it is the Science which ſhould teach ſo perfectly to underſtand the nature of man, and all things that may ſerve him for nutriments or remedies, that it might be eaſie for him, thereby to exempt himſelfe from all kinds of diſeaſes: for not to ſpeake of any other uſes thereof, this alone is weighty enough, to oblige the moſt inſenſible to favour the deſignes of a man, who hath already proved by the things he hath already found out, that there is great reaſon to expect from him the unfound remainder of that Science.

But there is an extraordinary neceſſity that the world ſhould know, you have proved that your ſelfe: and to this end it is requiſite you uſe a lit­tle violence to your own nature, and baniſh that too great modeſty, which hath hitherto hindered you from ſpeaking what you are bound to doe, both of your ſelfe and others. Yet I meane not not therefore to commit you to the learned of this age; the moſt part of thoſe, on whom this name is conferred, to wit, thoſe who cultivate (as they commonly call it) good literature, and the Lawyers have not any thing to doe in what I would have have you talk off. Divines and Phy­ſicians have as little too, unleſſe in the notion of Philoſophers: for Divinity depends not a jot on Phyſickes, nor yet Phyſick as at this day it is practiſed by the moſt learned and prudent in that Art: they are contented to follow the maximes and rules that a long experience hath taught them, and doe not ſo much contemne the lives of men, as to leave their judgement, whereon it often depends, on the uncertain ra­tiocinations of Schoole-Philoſophy: none then but the Philoſophers are unſatisfied, among whom all who have wit are on your ſide, and would rejoyce to ſee you manumit truth, ſo that the malignity of Pedants might not be able to oppreſſe her: for none but meere Pedants can be angry at what you have to ſay: and in regard they are the laughing-ſtock and contempt of moſt wel-bred men, you need not ſtand much on their diſpleaſure: beſides, your reputation hath made them already as much your enemies as they can be: and whereas your modeſty now cauſeth ſome of them not to fear to ſet upon you, I am confident, would you but extoll your ſelfe as you might, and ought, they would ſee themſelves ſo far beneath you, that there is not one of them but would be aſhamed to undertake you. I ſee no reaſon, then that may detaine you from boldly publiſhing, whatſoever you may judge ſerviceable to your deſigne: and no­thing ſeemes to me better for it then what you have already written in a letter to the reverend Father Dinet, which you cauſed to be printed ſeven yeers ſince, when he was Provinciall of the Jeſuites of France. Non ibi, ſay you ſpeak­ing of the Eſſayes you had publiſhed five or ſixe yeers before, unam aut alteram, ſed plus ſex­centis quaeſtionibus, quae ſic à nullo ante me fue­rant explicatae; ac quamvis multi hactenus mea ſcripta tranſver ſis ocul is inſpexerint, modiſque omnibus refutare conati ſunt, nemo tamen, quod ſciam, quicquam non verum potuit in iis re­perire: fiat enumeratiò quaeſtionum omnium, quae in tot ſaeculis, quibus aliae Philoſophiae viguerunt, ipſarum ope ſolutae ſunt, et fortè nec tam multae, nec tam illuſtres invenientur: quinimò profiteor ne unius quidem quaeſtionis ſolutionem, ope prin­cipiorum Peripatetice Philoſphiae peculiarium, datam unquam fuiſſe, quam non poſſum demon­ſtrare eſſe illegitimam, et falſam: fiat periculum; proponantur, non quidem omnes (neque enim openae­pretium puto multum temporis in eâ re impen­dere) ſed paucae aliquae ſelectiores, ſtabo promiſ­ſis, &c. Thus in ſpight of all your modeſty, the force of truth hath compelled you there, to write that you had ſtated in your firſt Eſſayes, which containe nought almoſt but the Diopticks and the meteors, above 600 queſtions of Philo­ſophy, which none before you knew how to do, and that although many lookt aſquint upon your writings, and ſought all manner of wayes to confute them, yet you knew not hitherto any who had pickt any untruth out of them: whereto you ſubjoyn, that if all the queſtions re­ſolved by all other kinds of Philoſophying, which have been in vogue ſince the world began were reckoned up one by one, they would not, it may be, be found ſo numerous, nor ſo eminent. Fur­thermore, you aſſure us, that by thoſe principles, peculiar to the Philoſphy attributed to Ariſtotle, which onely is now taught in the Schooles, no man ever yet knew how to find out the true ſo­lution of any one queſtion; and you abſolutely defie all thoſe who teach it to name any one plainly reſolved by them, in the ſolution where­of you can not demonſtrate ſome errour: now, theſe things having been written to a Provinciall of the Jeſuites, and publiſhed above ſeven yeers ſince, there is no doubt but ſome of the ableſt of that great ſociety, would have endeavoured to confute them, had not they been perfectly true, or if they could have been but ſo much as diſputed with any colour of reaſon: for not­withſtanding the little noiſe you make, all men know your reputation is already ſo great, & they are ſo much intereſſed to maintain, that what they teach is not bad, they can not pretend to ſay they ſlighted it: but all the learned know well enough, that there is nothing in the Phy­ſickes of the School, but what is dubious; and they know withall, that to be dubious in ſuch a matter, is not much better than to be falſe, be­cauſe a ſcience ought to be certaine, and de­monſtrative: ſo that they cannot thinke ſtrange, that you aſſure them their Phyſickes containe not the true ſolution of any one queſtion; for that ſignifies no more, but that it containes not the demonſtration of any unknown truth; and if any one examines your writings to confute them, he finds on the other ſide, that they containe no­thing but demonſtrations, concerning matters formerly unknown to all the world: wherefore being wiſe and adviſed, I wonder not that they hold their peace, but I marvell why you have not vouchſafed to take advantage of their ſilence, becauſe you could not have wiſhed any thing more to make it apparent how much difference there is betwixt your Phyſickes and others. And it is very important to obſerve the difference of them, that the ill opinion of thoſe who are em­ployed in the ſtate, and are moſt ſucceſſefull uſu­ally have of Philoſophy, hinder them not from underſtanding the worth of yours: for they commonly conjecture what ſhall befall, by what they have already ſeen to happen; and becauſe they never ſaw the publike reape any benefit by School Philoſophy unleſſe that it hath made many Pedants, they cannot imagine better is to be expected from yours, unleſſe they are brought to conſider that this being altoge­ther true, and that utterly falſe, their fruits muſt be different. In earneſt, it is a ſtrong argument to prove there is no truth in School Phyſickes, but to ſay it is inſtituted to teach all inventions profitable for life, and nevertheleſſe, though there have many been found out from time to time, yet it never was by the meanes of any of theſe Phyſickes, but only by chance, or cuſtom: or if any Science have contributed thereunto, it hath been only the Mathematicks: which alone of all humane Sciences hath been able to prove ſome indubitable truthes. I know well enough, the Philoſophers admit that for one branch of their Phyſickes; but in regard they were almoſt all of them ignorant in it, and it was no part of it, but on the other ſide true Phyſickes were a part of the Mathematicks, this can make no­thing for them: but the certainty already diſco­vered in the Mathematicks makes much for you: for it is a Science wherein you are acknowledged to be ſo excellent, and you have therein ſo over­topped envy, that even thoſe who are jealous of your eſtimation for other Sciences, uſe to ſay you ſurpaſſe all men in this, that by granting a commendation which they knew cannot be diſputed, they may be leſſe ſuſpected of calumny when they endeavour to rob you of others: and it is ſeen by what you have publiſhed concerning Geometry, that you there ſo determine how far humane capacity can reach, and which is the way of ſolving every manner of ſcruple, that it ſeemes you have reached the whole harveſt, whereof thſe who write before you have onely cropped ſome ears: and your ſucceſſours can be but gleaners, who ſhall gather up onely thoſe you were pleaſed to leave them: beſides, you have ſhewn, by the ſudden and eaſie ſolution of all queſtions, which thoſe who have tried you have propounded to you, that the Method you uſe for this purpoſe is ſo infallible that you never fail to find thereby, what ever the wit of man can, belonging to the things you ſeek after: ſo that to make it undoubted that you are able to bring Phyſicks to the lighteſt perfection, you are onely to prove, them to be a part of the Mathe­maticks, and you have already proved it plainly enough in your principles: when explaining all ſenſible Qualities, conſidering onely their great­neſſe, figures, and motions, you ſhewed that the viſible world, which is all the object of Phy­ſicks, containes only a ſmall part of the infinite bodies whereof the proprieties or Qualities may be imagined, conſiſts onely of theſe very things whereas the object of the Mathematickes con­taines all; the ſame may alſo be proved by the experience of all ages: for although from time to time many of the beſt wits, have beſtowed their time in the inveſtigation of Phyſick, as it can not be ſaid that any of them ever diſco­vered ought (that is, attained any true know­ledge of the nature of corporeall things) by any principle, that belonged not to the Mathema­ticks: whereas, by thoſe belonging to them, abundance of very uſefull things have been found out, to wit, almoſt all that is known of Aſtronomy, Chirurgery, and all Mechanicall arts: wherein, if there be any thing more then what belongs to this ſcience, it is not drawne from any other, but onely from certain obſer­vations, whoſe true cauſes are unknown; which cannot be conſidered ſeriouſly, but it muſt be confeſſed, that the knowledge of true Phyſicks is to be attained no way but by the Mathema­tickes; and your excellence in this not being doubted, there is nothing but may be ex­pected from you in that; yet there remaines one ſcruple, for that it is ſeen that all who have acquired ſome reputation in the Mathematicks, are not, for all that, capable to find out any thing in Phyſicks, nay, and ſome of them leſſe comprehend the things you have written there­of, than many who never learnt any Science at all: but it may be anſwered, that although un­doubtedly they who have wits apteſt to con­ceive the truths of the Mathematicks, are they who eaſieſt underſtand your Phyſicks, by reaſon all the arguments of theſe are deducted from the other; it happens not alwayes that theſe men have the greateſt reputation for the moſt learned in the Mathematicks; becauſe to acquire this re­putation it is neceſſary to ſtudy the bookes of thoſe who heretofore have written of this Science, which the moſt doe not, and oftentimes, thoſe who doe, endeavouring to attaine by labour what they cannot by the ſtrength of their wit, tire out their imagination, yea, hurt it, and ac­quire thereby many prejudices, which hinder them much more from conceiving the truths you write, than paſſing f or great Marhemati­cians: becauſe ſo few men apply themſelves to this Science, that of times there is but one of them in a whole Country; and though ſometimes there be more, they keep a great ſtir with it, in regard the little they underſtand hath coſt them a great deal of pains. Now, it is not uneaſie to apprehend the truths another man hath diſcovered: it is ſuf­ficient for that, that the brain be diſengaged of all ſorts of prejudices, and be willing to afford atten­tion to them; nor is it difficult to find ſome of a contrary bias to the reſt, as heretofore Thales, Py­thagoras, and Achimedes, and in our age Gilbert, Kepler, Galileo, Harvey, and ſome others. Laſtly, a man may, without much pains, imagine a body of Philoſophy, leſſe monſtrous, and grounded on conjectures more conformable to truth, than that which is extracted from the writings of Ariſtotle, which hath been done too by ſome in this age: but to frame one that containes only truths pro­ved by demonſtrations as clear and certaine as thoſe of the Mathematicks, there is none but you alone who have ſhewed us by your writings that you could compaſſe it. But as when an Architect hath laid all the foundations, & erected the chief walls of ſome vaſt building, none doubts that he is able to finiſh his deſigne, becauſe it is ſeen that he hath already done the hardeſt part of it: ſo thoſe who attentively have read your book of Principles, conſidering how you have there laid all the foundations of naturall Philoſophy, and how great are the conſequences of truths which you have therein exhibited, cannot doubt, that the Method you uſe is ſufficient, whereby you may make an end of finding out the utmoſt that can be diſcovered in Phyſicks: becauſe the things which you have already made known to wit the nature of the loadſtone, fire, aire, water earth, and all that appeares in the heavens, ſeem not to be leſſe difficult then thoſe which may be deſire.

Yet I muſt adde here, that let an Architect be never ſo expert in his art it is impoſſible hee ſhould finiſh the edifice hee hath begun if mate­rials requiſite are deficient: in like manner let your method be never ſo exact, yet you cannot make any further progreſſe in the explication of naturall cauſes, unleſs you be able to make re­quiſite experiments to determine their effects; which is the laſt of the three things, I believe, ought chiefly to be explained, becauſe moſt men conceive not how neceſſary experiments are, nor what expence they require; thoſe who, not ſtir­ring out of their ſtudy, nor caſting their eyes on any thing but their books, undertake to diſ­courſe of nature, may well tell how they would have created the world, had God given them authority, and power to do it; that is, they might deſcribe Chimera's that have as much A­nalogy with the imbecilitie of their wit, as the admirable beauty of this Univerſe, with the in­finite puiſſance of its Maker: but without a ſpi­rit truly divine, they cannot of themſelves, frame an Idea, of things, like that which God had to create them. And though your Method promiſe all that may be hoped for from humane wit, concerning the enquiry after truth in the Scien­ces, yet it doth not promiſe to teach Prophecie; but to deduce from certain things laid down, all truths that may from thence be deducted: and the things laid down in Phyſicks can be nothing but experiments. Moreover becauſe experi­ments are of two ſorts; ſome eaſie, that depend only on the reflexion a man makes on things re­preſented to the ſenſes of themſelves; others, more rare and difficult, which are not attained without ſome ſtudy, and expence: it may bee obſerved, that you have already inſerted in your writings all that ſeems may be gahtered out of eaſie experiments, and alſo the rareſt too, that you could learn out of books, For beſides your explaining the nature of all qualities that move the ſenſes, and the moſt ordinary bodies on the earth, as fire, air, water, and ſome others in them, you have alſo therein given an account of all that hath been obſerved hitherto in the heavens, of all the properties of the Loadſtone, and many Chymicall obſervations; So that there is no reaſon to expect any more from you con­cerning Phyſicks, till you have made more expe­riments, whereof you might enquire the cauſes; And I wonder not, that you undertake not to try theſe experiments at your own charges; For, I know, the enquirie after the ſmalleſt things coſt a great deal: and not to quote Chymiſts, nor the reſt of the hunters after ſecrets, who uſe to undoe themſelves at that trade, I heard ſay that the Loadſtone only coſt Gilbert above 50000 crowns, though he were a man of very great parts, as he hath ſhewed by being the firſt who diſcovered the chief properties of that ſtone. I have alſo ſeen the Advancement to Learning, and the New Atlantis, of my Lord Chancellour Bacon, who, of all them that have written be­fore you, ſeems to me the man who had the beſt notions, concerning the method to be held to bring the Phyſicks to their perfection; but the whole Revenue of two or three of the richeſt Kings on the earth, would not be enough to ſet all things he requires for this purpoſe on work. And although I think you doe not need ſo many ſorts of experiments as hee imagines becauſe you may ſupply many, as well by your dexterity, as the knowledge of truths you have already found: yet conſidering that the number of par­ticular bodies unexamined, is almoſt infinite that there is not any one but hath a great many ſeve­rall properties and whereof ſeverall tryals may be made, to take up the time, and labour of ma­ny men; that according to the rules of your me­thod, it is neceſſary at once to examine all things who have any affinitie between them, the better to marke their differences, and to make ſuch quantities as you may be aſſured, that ſo you may profitably make uſe at the ſame time of more ſeverall experiments, than the labour of a great many able men could furniſh you withall, and laſtly, that you cannot get theſe able men but at a great rate, becauſe if ſome would em­ploy themſelves gratis, they would not be obedi­ent enough to your orders, and would only give you occaſion to loſe time: conſidering, I ſay, all theſe things, I eaſily comprehend, you cannot handſomly finiſh the deſigne you have begun in your principles, that is, particularly to lay open the nature of all Minerals, Plants, animals and man, as you have already done all the elements of the earth, and all obſervable in the heavens, unleſſe the publique defray the expences neceſ­ſary for that purpoſe; and the more liberall they ſhall be to you, the better you ſhall be able to goe through with your deſigne.

Now, becauſe all theſe things may be eaſily comprehended by every one, and are all ſo true, they cannot be doubted, I am confident, that if you repreſented them in ſuch a manner, as they might come to the knowledge of thoſe, to whom God hath given power to command the people of the earth, and charge alſo to doe their utmoſt to advance the common good, there is none of them but would contribute to a deſigne ſo manifeſtly profitable to the whole world; and though out France, which is your Country, be ſo mighty a State, that you might eaſily ob­tain from her alone whatſoever is requiſite to this purpoſe, yet becauſe other Nations are no leſs intereſſed therein than ſhee, I am confident many would be generous enough not to give her place in that duty: and that there would not any bee ſo barbarous as not to put in a hand.

But if all that I have written be not enough to make you of another humour, pray, at leaſt oblige me ſo farre as to ſend me your Treatiſe of the Paſſions, and give me leave to adde a Preface to it, wherewith it may be printed. I will ſee, it ſhall be ſo done, that there ſhall be nothing you can diſlike in it but it ſhall be ſo conformable to the reſentment of all thoſe who have either wit or vertue, that no man after hee hath read it, but ſhall participate in the zeale I have to the advancement of Sciences, and to be, &c.

Paris,Nov. 6. 1648.

In anſwer to the precedent letter.

Among the many injuries and taunts I find in the long letter you tooke the paines to write to me, I obſerve ſo many things to my advantage, that ſhould you put it to be printed, as you declare you will, I am afraid, it would be imagined there were a greater combination betwixt us than there is, and I had entreated you to inſert many things that modeſty would not ſuffer me my ſelf to pub­liſh to the world. Wherfore I will not here inſiſt in anſwering every particular, I will onely tell you two rea­ſons that, me thinkes, might deterre you from it: the firſt is, I have not any conceit, that the deſigne, I ſuppoſe, you had in writing it can ſucceed; the ſecond, that I am no whit of that humour you ſuppoſe me, that neither indignation nor diſtaſte hath taken away my deſire to be ſer­viceable to the publick, whereunto I think my ſelfe very much obliged, for that thoſe things I have already publiſhed have been by many favour­ably received. That I did not formerly beſtow what I had written of the Paſſions on you, was becauſe I would not be engaged to let ſome others ſee it who would have made no uſe of it: for ſince I compiled it to be read onely by a Princeſſe, whoſe wit is ſo far above the common pitch, that ſhe con­ceives without difficulty what ſeemes hardeſt to our Doctours; I onely purpoſed to unfold what therein was new. And that you may not doubt what I ſay, I promiſe you to review that tract of the Paſſions, and to add what I conceive neceſſary to make it more intelligible, and then, I will ſend it you, to doe what you pleaſe with it: for I am, &c.

Egmont. Dece. 4. 1648.

A ſecond letter to Mouſieur des Cartes.

It is a long while ſince you have made me ex­pect your tract of the Paſſions, which I begin to deſpaire of, and fancy with my ſelfe that you promiſed it to me onely to hinder me from pub­liſhing the letter I formerly writ to you: for I have reaſon to beleeve that you would be vext, if a man went about to barre you of the excuſe you make to finiſh your Phyſickes, and my deſigne in that letter was to barre you, ſince the reaſons I have there laid down, are ſuch, that me thinkes they cannot be read by any one who hath the leaſt ſeruple of reſpect to honour or vertue, but they will incite him to wiſh as I doe, that you might obtaine of the publick what is requiſite for the experiments you ſay are neceſſary; and I hoped it might happily alight into the hands of ſome who had power to make that deſire effectuall, whether becauſe they had acceſſe to thoſe who diſpoſe the publick treaſure, or becauſe they diſpence it themſelves: ſo I was confident I ſhould find you doing whether you would or no: for I know you have ſo great a hart that you would not fail to repay what ſhould thus be given you, with uſury, and that would make you abſolutely ſhake off that careleſneſſe, whereof at preſent I cannot refraine from ac­cuſing you, although I am, &c.

July 23. 1649.

In anſwer to the ſecond Letter.

I am very guiltleſſe of the ſlight you are pleaſed to beleeve I uſed, to hinder the long Letter you ſent me laſt yeere from being publiſhed: for beſides, that I cannot thinke it can any whit produce the effect you pretend, I have not ſuch a propenſion to idleneſſe, that the feare of labour whereunto I ſhould be tied, were I to dive into many experiments, could prevaile over the de­ſire I have to inſtruct my ſelfe, and write any thing uſefull for other men, had I from the publick received conveniences to doe it. I cannot ſo well cleare my ſelfe of the careleſſeneſſe you charge me with: for I confeſſe, I have beene longer in reviewing the little tract I ſend you, than I was in making it, and yet I have added to it but very few things, and have not a whit altered the diſcourſe, which is ſo plain and briefe, that it will be eaſily known thereby, my deſigne was not to lay open the Paſſions like an Oratour, nor yet a Morall Philoſopher, but onely as a Phyſician: ſo I foreſee that this tract will have no better ſucceſſe than my other writ­ings: and although the title (it may be) may invite more people to read it, yet it will not give ſatisfaction to any b ut them who take the paines to examine it conſiderately. Such as it is, I com­mit it to you, &c.

Egmont. Aug. 14. 1649.