MAGNETICAL Advertisements: OR  
DIVERS PERTINENT observations, and approved experiments, concerning the natures and properties of the Loadstone.  
Very pleasant for knowledge, and most needful for practise, of traveling, or framing of Instruments fit for travelers both by Sea and Land.  
Whereunto is annexed a brief Discovery of the idle Animadversions of MARK RIDLEY Dr. in Physic, upon this Treatise entitled Magnetical Advertisements.  ACTS 17. 26. He hath made of one blood all nations of men for to dwell on the face of the earth, and hath determined the times before appointed, and the bounds of their habitation, that they should seek the Lord, etc. 
The second Edition.  
LONDON, Printed by Edward Griffin for Timothy Barlow, and are to be sold at his shop in Paul's Churchyard, at the sign of Time. 1618.   

TO THE RIGHT WORSHIPFUL, DIScreet, and learned Gentleman, S it DUDLEY DIGGES Knight.  
SIR, the nature, powerfulness, and strange properties of the loadstone are such, that the more they are known, the more they are justly admired in their most lively expressing that infinite power, and goodness of our God, who hath created so precious a jewel for the profitable use of man, and for the enlarging, and setting forth of his own glory. Into the search of which admirable and secret virtues myself by the space of these forty years, have somewhat entered (as my leisure and occasions would serve, and at by times) partly by reading other men's writings, and partly by my own industry and practise: Whereby what I have collected, and found, this little Treatise will show. Which, whether it be any thing, or nothing, I do refer unto the judicious Readers consideration, but in special to your favourable construction, and good acceptance.  
Many years since divers of my good friends, and among them some honourable persons, were very desirous that I should publish such observations as I had collected, both before, and also after the setting forth of D. hearts book: And none more earnest herein then D. Gilbert himself, unto whom I communicated what I had observed of myself, and what I had built upon his foundation of the Magnetisme of the earth. Both which he liked well and wished me to publish them, as I remember at the time of our private conference, as may further appear by letters that I received from him; which I have to show under his own hand.  
But above all others, the persuasions of that learned honourable Gentleman, Sir Thomas Challenor, late Chamberlain unto the Mirror of honour Prince Henry prevailed most with me. Unto whom I was all the time that I attended that Prince his highness, for his love and courtesy, much beholding. Whereupon about seven years since I delivered unto him this Treatise, finished almost as now it is, saving some few additions upon necessary occasions. But that Copy was either mislaied or embeseled, that he lost it; About three years since he sent earnestly unto me for an other Copy: which also he received, promising me by his letters, that within three months he would put that to the press, and that it should be carefully and correctly performed: But what is become even of that also I know not: Only this I am sure of that I have met with many portraitures of my Magnetical implements, and divers of my propositions set abroad in print in another man's name, and yet some of them not rightly understood by the party usurping them.  
Now that it hath pleased God to take Sir Thomas Challenor and that upon inquiry I can hear no tidings of those my lost labours, and knowing that divers are very desirous to see them, I have once again revived my scattered papers, collected them together, & made choice of yourself to whom to entitle (according unto our usual courtesies) these magneticals; your worthy self I say in many respects: First, because your rare learning joined with so great piety, accompanied with so pleasing a carriage of yourself towards every man is such, as causeth all good men which know you, to love you, by force of a natural sympathy not unlike the appetite of concourse & conjunction whereby our very Magnets do affect their proper objects. And this was very conspicuous in our renowned judicious Prince Henry, who loved you singularly well for your virtues, and delighted no less to confer with you for your knowledge in matters appertaining unto Discoveries and Cosmographical learn, in the which his highness was more than vulgarly skilful.  
Another is, the glorious favour which I see reflected upon you from that most reverend and singular ornament of our Church and State, rejoicing in God's blessing of his labours in your education: like as God hath hitherto blessed him in all things, and not only my prayers and such as I am who are so much bounden unto him, but the prayers of many thousands that never saw him, will not cease to beseech the Almighty long to preserve him. and always to prosper him in his godly proceedings: Wherefore this extraordinary respect which he hath unto you, both is and must be a commanding motive unto me to show my good will by the best poor means that I can toward you.  
Yet one more I have, which is this: That whereas a worthy society of Gentlemen and Merchants is very highly and justly commended and honoured of all men, for their great charges in their constant and indefatigable proceedings, for discoveries of unknown passages to new Countries and Nations, for the further advancement of God's glory, the honour of our King, and principal benefit of the whole Kingdom; In remembering of those honourable attempts, you must in no wise be forgotten, and especially in a Treatise mentioning the virtues, and properties of the Loadstone, being the leader and guide to these admirable exploits, who besides your sowed knowledge herein, do with great constancy join both your purse and counsel for the atcheiuing of them, yea and that without expectation, or hope of private gain, but only of your noble generosity, knowing full well, that the advancement of God's glory is absolutely of itself the greatest gain with a contented mind; Wherewith, he that only is all-and selfe-sufficient, every you more and more in this world, and to your eternal happiness, most abundantly and perfectly satisfy you, by making you drink of the river of his pleasures in the world to come; Amen.  
Yours with all hearty affection  
WILLIAM BARLOWE.   

THE PREFACE to the Reader.  
THat wonderful property of the body of the whole earth, called the Magnetical virtue (most admirably found out, & as learnedly demonstrated by Doctor Gilbert Physician unto our late renowned Sovereign Queen Elizabeth of happy memory) is the very true fountain of all Magnetical knowledge. So that although certain properties of the Loadstone were known before, yet all the reasons of those properties were utterly unknown, and never before revealed (as I take it) unto the sons of men. And although as yet many do doubt and mistrust that the earth itself hath no such virtue, I do nothing wonder at it, because before I read his learned works, and had tried many of his experiments with mine own hands, and had conferred with great travelers, and perused the observations of our chiefest Navigators both for their variations, and declinations, I never believed it myself. But this I may truly affirm that searching with diligence his first five books, and making trial of all those propositions which I judged to be of importance, I always found the main drift, touching this point, certain, constant, and agreeable to the diligent obsernations of divers men of experience; although in some other matters of the Loadstone his experiments and mine did sometimes disagree, as I signified to himself in his life time, which he did take in very good part, as I have yet his own letters to show. But concerning his sixth Book entreating of the motion of the earth, I think there is no man living farther from believing it, than myself, being nothing at all persuaded there unto, by the reasons of other men, which he allegeth, and as little or less (if it were possible) by those his inventions, endeavouring to prove the motion of the earth by the earths Magnetical force and virtue.  
Amicus Socrates, Amicus Plato, sed magis amica veritas is the only cause why I do embrace his judgement, in the one, and refuse it in the other, in matters of this nature following this Rule:  Nullius addictus jurare in verba Magistri. 
But to return to the Magnetisme of the whole earth, I do hold it to be one of the rarest, and excellent est inventions, and the best followed by him, with evident proofs and of the greatest consequence for the admirable art of Navigation that ever was found out since the Creation of the world, so that it may well be said of him touching that point.  

Exegit monumentum aere perennius  
Regalique situ pyramidum altius,   
in respect of the manifold use and commodity thereof in the doings of this life. The properties of the Magnet serving not only for Sea-affaires, but also for traveling by Land in vast and solitary deserts, for movable Sun-dyalls' in all places of the world, for the more ready and exact chorography of any Country, or the true plotting of any ground, and for the following of any Mineral vain that is void of Iron under the earth, for pioneers and diggers in Mines. And in all this appeareth the wonderful power and goodness of God who hath vouchsafed to reveal unto the weak knowledge of man now towards the end of the world, his admirable treasure, before unknown, of his powerful Creation, by effect so plain unto the mean est capacity: And that out of a base, contemptible and dead creature, as it seemeth to be, and yet filled with such excellent and wonderful virtue, that all the Gems of the world, have not the like; neither if it were wanting could supply the want thereof, or countervail the benefit that it bringeth to the life of man.  
Claudianus (a famous Poet) well near twelve hundred years since, saith as much in commendation of the magnet, when as yet the sereditical or Iron-drawing property thereof was only known.  

— Lapis est cognomine Magnes  
Decolor, obscurus, vilis etc.   
And again,  

Sed nova si nigri videas miracula saxi,  
Tunc superat pulchros cultus, & quicquid Eoïs'  
Indus littoribus rubra scrutatur in algâ.   
But what would he not have said, had he seen the true closet indeed of all Magnetical miracles unlocked, and in glorious manner set wide open as now it is at this day.  
Many of our Nation both Gentlemen and others of excellent wits and lovers of these knowledges, not able to read Doctor hearts Book in Latin, have been (ever since the first publishing thereof) exceeding desirous to have it translated into English, but hitherto no man hath done it, neither (to my knowledge) as yet goeth about any such matter, whereof one principal cause is that there are very few that understand his Book, because they have not Lodestones of divers forms, but especially round ones: Also such versory needles fitly framed, and artificially placed upon their pins, and other such implements, as he doth there prescribe, wherewith being furnished, as they read his propositions in words, they might still see the truth of them in the things themselves, according as himself forewarneth that these skills must be learned Ex rebus ipsis non solum ex libris, out of the things themselves and not only out of Books. A second cause may be for that there are divers words of Art in the whole course of this book proper to this subject, and fit to the explanation of his figures and diagrams which cannot be understood but by the help of the Mathematics, and good traveling in the Magnetical practice.  
Moreover his alleging of other men's erroneous opinions concerning this Argument, and his confutations thereof, may seem at the first to a young beginner somewhat harsh and tedious. Both which I suppose in the English translation (if any were) might well be omitted: like as in this my Treatise I think it not altogether so pertinent to handle them all.  
And a sport it is to behold divers of smart wits, and such as ween themselves to be so great Clerks, that they will adventure boldly to dispute de omni scibili, how miserably they run their wits on ground, when only by a slender reading over of his book, or most commonly some part thereof, they will take upon them to define, control, and discourse of those matters fearing nothing more than that of the Poet,  

— mihi turpe relinqui est  
Et quod non didici sane nescire fateri.   
For being urged by divers of our Gentlemen (among whom these knowledges are had now a days in some request) somewhat they must speak, which must be either superciliously to scorn such things, as vanities, because themselves understand them not, or else with slender ostentation to blunder out their masked ignorance, supposing it to be enough for them to say that they have read Dr. hearts Book, and so to use that for a Supersedeas to acquit them of any farther inquiry. But many, being now at length weary to take such counterfeit shows for good payment, do seriously seek to have some sound knowledge of the things themselves, and not to depend upon other men's extravagant disputes, but to be their own judges in matters that concern themselves, and are subject to their own senses and reasons, and especially because some of them must adventure their whole estates, yea and also their lives upon the right understanding of some Magnetical conclusions.  
Wherefore upon the earnest longing of certain mine Honourable and Worshipful friends, and for the singular love that I bear to the lovers and practisers of the worthy Art of Navigation, and to satisfy the commendable desires of such as like to have some insight (though themselves be not praectizers in these matters of admirable knowledge, and great utility) I have undertaken to contrive all the chiefest points of this most necessary skill, and the use of them in this short Treatise.  
Not meaning to translate Doctor hearts book, but to take those thing out of it which I shall think fit for this purpose, which are only the Magnetisme of the whole earth, and some of the consequents thereof, and to add the rest of mine own industry: Wherein I may be bold after asort to challenge a right, as having endeavoured to get some insight in this argument (a matter well known to divers) above the space of twenty years ere Doctor hearts book saw light. And in very deed I communicated many of my observations with him, above one whole year before he put it out in print. To be short, of all that I shall set down in this Treatise my request is, that the Reader will admit nothing but that which shall be confirmed by good reason, or undoubted experiments. And I purpose (God willing) to tie myself, as strictly unto this rule as ever any man did that hath written of the like argument, making it even a matter of conscienae to deliver any thing herein for certainty, that myself shall not know to be sound. And so by this means shall I neither abuse the Reader with any untrue assertion, nor injury so certain and so excellent a knowledge with any doubtful or unapproveable conclusions.   

Contents of this Treatise.  

CHAP. I. OF the Magnetical power of the whole Globe of the Earth.  
CHAP. II. Of the ambiguity of the North and Sooth ends of Magnets and Magnetical bodies explained, and Doctor Gilbert therein defended.  
CHAP. III. Certain general observations of the nature and properties of the Loadstone.  
CHAP. FOUR By what means the chiefest points of any Magnet of what form soever may easily be found out.  
CHAP. V. The manner of Capping both with single and double Caps, and the nature of them.  
CHAP. VI Of cementing and peicing of Lodestones  
CHAP. VII. Of the variation of the Magnetical Needle with the Appurtenances thereto belonging.  
CHAP. VIII. A discovery of Errors committed in the making and touching Magnetical Needs and Wiars of sailing Compasses, with an advise for the true and right making and touching of them.  
CHAP. IX. Of the touching with a Loadstone capped and without the Cap.  
CHAP. X. Of the fashioning of the Compass Needle.  
CHAP. XI. A Sailing Compass fitted for observing at Sea the variation, amplitude of either Sun, or Stars, Capes, or trending, etc.  
CHAP. XII. A comparison of the several uses of the horizontal, and Inclinatory Magnetical Needles.   
A true copy of one of D. hearts letters written to the Author, concerning his Magnetical Experiments.   

MAGNETICAL Advertisements.  

CHAP. I. Of the magnetical power and force of the whole Globe of the Earth.  
COncerning the Magnetical force of the whole body of the Earth, I have selected these experiments to prove it.  
Take any piece of solid earth that hath some toughness to hold together, and will abide the fire, as any sort of clay, or brick (which sometimes was clay) fashion it in such manner that it be uniformly extended towards both ends (the oval or long figure is fittest for our purpose) put it into a fire of charcoles, increasing the heat by little and little, and at the length with often blowing, make it thoroughly as red hot as you can: let it remain so for the space of half an hour, or more, that thereby all superfluous moisture may be consumed, and adverse qualities separated from it, then take it forth, and let it cool of itself, being first set North and South, with either end answerable to the variation of the place, not parallel unto the Horizon, but elevated answerable to the Latitude as near as you can. Certain it is that this piece of earth thus ordered, will sensibly show you that it hath true Magnetical virtue. But here before I proceed any farther I must deliver unto you a necessary observation: There are two kinds of Attractions (as they are commonly called) the one Magnetical, the other electrical. The Magnetical hath always special respect unto the North & South points of the magnet or Magnetical body. The electrical body hath no manner of respect unto any one point of the electrical body, more than another: And by this difference these two kinds of Attractions are easily discerned; As also by this, look what end of the Magnetical needle the one end of the Magnet doth draw, the other will chase away; but the electrical body draweth alike at all ends. And thirdly after this sort, lap this electrical body in a paper and it will draw nothing at all, but interposition of brass or of a stone wall within the orb of the Magnets virtue, doth nothing weaken the same, or hinder his effect towards his peculiar object. Notwithstanding (to speak properly) Attraction pertaineth only to electrical bodies, because the whole attractive virtue is only in the electrical body itself, and nothing at all in the thing that is attracted. The Attraction (commonly so called) of the Loadstone is rightly to be termed, Concursion, Confluence, or Coition, because it is the running or vigorous meeting together of two Magnetical bodies having a mutual inclination the one to join with the other, or by any other name, bearing like sense. For the true knowledge thereof, being but lately as a stranger arrived amongst us, common use  
(Quempenes arbitrium est, & ius & normal loquendi.) hath as yet scant suited it, with a convenient name to express this property; So that Magnetical Concursion is never but between two bodies, such as both of them are Magnetical; As of one Loadstone with another, or of a Loadstone with iron or steel, or iron oar if it be prepared, or between two pieces of iron or steel that are revived with a Loadstone; for indeed the Loadstone can but revive, and multiply Magnetical force in a body that naturally hath it in some measure before: but cannot infuse it into any thing, that before is utterly void of it, as of metals, in iron or steel, and not in gold, silver, brass, etc. Electrum in this argument is named that which is either Amber in substance, or at the least of the quality, and that Amber, being rubbed, hath, to take up moats, feathers, straws, sticks, and other small things. The which property is also in ieate, brimstone, hard wax, (if it be smooth) and in infinite other things both natural and compound; all which because of that quality in this argument are termed electrical bodies, and their taking up of things is called electrical attraction, having only a slender resemblance, and no truth of the Magnetical quality. But that abovementioned piece of earth, prepared in such sort as is before prescribed, will by Magnetical concursion show itself to be a true Magnetical body. For the one end of the Magnetical needle will covet towards the one of the prepared mass, and fly from the other. And chose also, though it will do both but weakly, not with power comparable to a natural Loadstone, yet as truly as that. That end which cooled toward the South, will draw the true North end of the needle, and that end which cooled toward the North will draw the true South end of the needle. If so be as yet you will have another infallible argument, do thus: Mark what end draweth the North end of the needle, afterward put the new made Magnet into the fire again, and when it hath been glowing for the space of half a quarter of an hour, take it out and cool it being placed with that marked end toward the North, most assuredly that end now will draw the South end of the needle, & the North end of the needle will shun it, which before approached unto it. The reason here of is, because the fire having abolished all the former Magnetical quality of that mass wherewith it was in a contrary position affected in the former cooling, now leaveth it apt and fit to receive any other new impression: which presently it taketh again either regularly, if in the cooling it be placed with the ends to the North and South, or (if it be placed otherwise) confusedly, by the Magnetical force and virtue of the whole body of the earth, by regular and confused, this is the meaning. Take any lump of earth, or any brick-bat ordered in this sort, certain it is that this lump of earth or bricke-bat hath some magnetical virtue therein, yet so feeble and weak, that our sense cannot discern it, because of the unfitness of the form, and the confused dispersion of that weak force, through the whole body thereof. Then suppose you will bring either of these into an extended oval form, which is most apt (as before I said) for any body magnetical to show his force, yet this will help it nothing at all of itself, as you may easily make experience in every Loadstone. For if you take a loadstone of a confused form, it is not enough to bring it into a convenient oval, except with diligence you reserve the points of the North and South in the two ends thereof, for if you leave the points in the sides you mar it with this oval form. For the stone will not lightly be of one quarter of the force, it was ofbefore; For the oval form giveth it no virtue, but is the fittest for it to show the uttermost of that strength, which of itself it had before, if you observe the due points, and not otherwise. But in this earth and brick it is not possible to find the due points in such sort as you may in a Loadstone, because of the weakness of the magnetical force therein contained. And therefore you cannot bring that into a regular oval form, to have the due points in the very ends. But if you first make it into an oval form, and by the fire take away the confused magnetical force, and all other perverse qualities thereof, that being by nature a magnetical body in his cooling before specified, receiveth presently by that unresistible power of the earth, his magnetical virtue, according unto that form, and will regularly have his due points precisely in the ends, without any confusion. johannes Baptista-Porta Neapolitanus, writeth that he did make trial of the way that Paracelsus hath set down for to increase the virtue of a magnet, namely to heat him red hot in the fire, and to quench him in the oil of Crocus Martis: And Baptista Porta saith, that he found it a detestable falsehood. For saith he, he is so far from increasing his virtue, as that (being once red hot) he looseth all his own, past all recovery. But for all this that he saith, I doubt whether Paracelsus be justly reproved or not, for by mine own experience I know that the heating of a Loadstone until he be red hot doth weaken a loadstone, but taketh not away all his force, and in my trial here of I found a very manifest proof of the magnetisme of the earth, which I thought necessary for to insert in this place. I have made this trial of Fragments of magnets of divers kinds, and also of divers kinds of Iron Mines which are next in degree unto magnets, namely after this sort. Heat him in the fire by little and little (for fear of breaking) until he be red hot, then take him out and let him cool, then mark (with chalk or what you please) those parts that respect the North and South and you shall find those marked places, the North, and South Poles of the Magnet: put him into the fire again, until he be red hot, and cool him contrarily, and you shall have the contrary effect. Therefore if Baptista Porta did make his trial with a Loadstone very long in form, and chanced (for Master D. hearts mystery of the Earth's magnetisme, was not then revealed) for to cool him in his oil of Crocus Martis with his ends East and West, the axis of the stone being then overth wart in the middle, it were no marvel if he found no force in the ends. And I do not think it improbable, but that Paracelsus way may do some good rightly used. Doctor Gilbert writech that some Iron mine, will affect a magnetical needle, as it is of itself, being unprepared by fire: but as yet I never could find any such, but this I have often tried, that it being of no manner of magnetical virtue of itself no more than a flintstone unprepared by fire, being made red hot, and cooled, is presently impregnated with very apparent magnetical virtue, according to the situation that he is cooled in, and although you heat and cool him often, and divers ways, he will still keep his virtue, according to the situations, of his cooling. And some Iron Mines I have found, which being but in this sort prepared have had as strong force as some natural magnets have had. It is the goodness of the Loadstone joined with a fit form that will show great force. For as a very good form with base substance can do but very little, so the substance of the Loadstone be it never so excellent, except it have some convenient form, is not available. For example, an excellent loadstone of a pound weight and of a good fashion, being used artificially, may take up four pounds of Iron; beat it into small powder, and it shall be of no force to take up one ounce of Iron; yea I am very well assured that half an ounce of a Loadstone of good fashion, and of like virtue will take up more than that pound will do being beaten into powder. Whence, (to add this by the way) it appeareth manifestly, that it is a great error of those Physicians and Surgeons, which to remedy ruptures, do prescribe unto their Patients to take the powder of a Loadstone inwardly, and the small filing of iron mingled in some plaster outwardly: supposing that herein the magnetical drawing should do great wonders. Whereas they consider not that the stone being dissolved into powder, every little particle of the dust hath two points contrary, the one drawing to, the other repelling and putting from: and so being thus confounded by a contrary working doth much more harm, then good with his magnetical quality. As for the astringent, and drying properties of the Loadstone I leave them to the diligent observation and judgement of the skilful in physic. But to return to our purpose, and to allege this also, besides the former manifest proof, if the earth were not by nature a magnetical body, the afore mentioned piece of earth could not receive from a Loadstone any magnetical power: But most certain it is, and by many undoubted experiments confirmed, that it will evidently receive magnetical power, from a Loadstone: therefore it is manifest that the earth is by nature a magnetical body. Furthermore, as among all the metals iron doth incomparably more resemble the earth in substance then any other doth, it likewise doth more participate with the earth in quality, and principally in the magnetical peculiar property hereof, as notorious experience declareth, yea every piece of iron oar, being naturally (as D. Gilbert showeth) a magnet, although of feeble force, and all magnets being a kind of iron oar, is the very cause, that only iron or steel, and no other metal is capable of that virtue, namely to have that revived, and multiplied by the vicinity of a magnet, which at the first in some measure, was original in itself, as it is aforesaid; It is also well known, that the magnet is a Stone most commonly of invincible hardness, nothing inferior to any iron or steel of the excellentest sort, notwithstanding sometimes we see of them that are nothing, but a dry lump of earth, and yet of those also some stronger in virtue, then divers of the hard stony ones are: Which earthly magnets if a man assay to bring it into a fashion by grinding on a grinding stone (according to the common use) they will consume into very mud in the water. Now (to draw towards an end of this matter) albeit the magnetical virtue be most eminent in the magnet, as in the precise and perfect subject thereof: yet is the self same quality, in a meaner degree, evidently to be discerned in every piece of earth, prepared and ordered (as is aforesaid) yea although it be not cooled with his ends North and South, that it may take his magnetical force from the virtue of the earth, for if you cool it with his ends but East and West and set two Lodestones in the cooling, the one at one end and the other at the other end, it will receive a sensible and apparent magnetical virtue according to those points of the Loadstone that were applied unto it, namely that end which was next the South point of the Loadstone will have a North properly, and that end that was next the North point, will have a South property: yea if you set the North part of two loadstones unto each end, both ends of this new made magnet will have a South property; And chose if you apply the South ends of two magnets, both his ends will have a North property; And those properties before mentioned will show themselves to be magnetical, because whether end of this new magnet draweth any one end of a magnetical needle, the same will chase away the other: which is proper only unto magnets, and magnetical bodies. After the like sort, only by application of two strong loadstones by the space of 24. hours you may alter the points of any base loadstone, which you would, and make them both North or South as you please: so that the loadstone which you would alter be but base in quality, and not great in substance, and that the other be of a reasonable bigness, and good strength. And this virtue by such application of two loadstones I have often found effectual in new brick lately taken from the kill without any farther putting into the fire at all; And although it be against the nature of a loadstone to have both his ends naturally of one virtue, that is to say, both of them of a North property, or both of them of a South property: yet here it is to be understood, that it is the forcible violence of the strong ones, being applied jointly unto each end of the weak, that do chase the contrary property of the weak one into the middle thereof: And therefore if you divide this weak one in the middle, then both those ends, which being joined together were the middle, (where no loadstone can show any virtue) being now disjoined, and become ends, will presently show a contrary property (according unto magnetical nature) unto the other two ends.   

CHAP. II. The ambiguity of the North and South ends of Magnets and Magnetical bodies explained, and Doctor Gilbert therein defended.  
THere is not any one error that breedeth a greater confusion in magnetical knowledge, than the mistaking of the right understanding of the true North and South ends, aswell in magnets themselves, as also in magnetical bodies, who soever therefore that will take a little pains in the beginning for to understand this well, shall free himself from many intricate difficulties in this argument, which otherwise must needs befall him; wherein some having limed themselves, have fallen into many errors, every one still begetting another worse than himself. All those which did write before Doctor Gilbert did name that end of a magnet which being placed in a wooden dish, and set to swim in water, would turn and settle itself towards the North, the North end of the magnet; and the other the South end. And even so did they of all Dial-needles, Compasses and magnetical bodies. But Doctor Gilbert, not for any newfangled innovation, or self-conceit, but upon good reason and firm demonstration avoucheth and proveth the contrary, and clearly showeth, that the former vulgar assertion seriously defended, tendeth unto the overthrow of all magnetical Philosophy, by undermining (as it were) the whole frame thereof; and yet in common speech the old rule may hold, Loquendum cum vulgo sentiendum cum sapientibus. For it would seem a strange speech unto a Mariner to tell him that his Flower de luce were become the South point of his compass, and yet this assertion is most true, and certain that it is the North end of every magnet and magnetical body, that being placed in a thin wooden dish in water, or any magnetical needle upon his pin, which setteth itself and pointeth unto the South, and it is the South end which pointeth unto the North. For proof hereof, take these words of North and South in whether of the two former significations you please, and make trial thereof in any two magnets, or any two magnetical bodies, so placed that they may freely turn according unto their natures, and you shall always see a natural inclination of the contrary ends of the one unto the contrary ends of the other, as of the North end of the one unto the South end of the other, and reciprocated of the South of the one to the North of the other; But the ends in the one and the other will always fly from those of like denomination, as the North end of the one from the North end of the other, and the South end of the one from the South end of the other.  
For as much then as all magnets themselves, and all magnetical bodies (being so placed as they may have their free motion) compose themselves magnetically towards the Poles of the earth, it must needs be that it is the true natural South end of the Magnet or Magnetical needle, that pointeth towards the North of the Earth: and it is the true natural North end of the Magnet or Magnetical needle that pointeth towards the South of the Earth, because the contrary ends do affect one an other, and each of them do naturally fly, the one end of the one, from that end of the other, which is of like denomination unto itself: for example, In this following Diagram of the whole Magnet, E. A, is supposed to note the true natural North end thereof, and B. the South end.  
This Magnet being placed in a wooden dish, swimming in water, freely must, and will, of Magnetical necessity, with his true North end, A. settle himself so, that A. must point towards the South of the Earth. And the South end, B. towards the North of the Earth: Because all Magnets and all Magnetical bodies, do naturally affect, the one the contrary end of the other, and do avoid and fly from their ends of like denomination.  
Now for a further consideration of these properties suppose that you will cut of a piece of this Magnet meridionally, viz. C. D: manifest experience will show, that C, which did in nature participate with A. in the entire Magnet, E: (as being both of the true North part thereof) now being separated, will not abide it. In like manner D, of the other end of the little one, will not abide, B: of the great one, with whom being entire in nature he did participate, as being both true Southerly parts of the entire Magnet, E: And that because the ends of like denomination of any two Magnets, do naturally fly the one from the other.   

CHAP. III. Certain general observations of the nature and properties of the Loadstone.  
LOadstones of divers and sundry parts of the world as of Norway, Elva, Bengala, etc. have one and the self-same property directive, I mean of showing the North and South, and also the self-same points respective declining or dipping under the Horizon. They do likewise agree in their variations, and each one will draw iron, and likewise one another. Every Loadstone, of what form soever he be, hath either actually or potentially two points, the one Northern, the other Southern. Actually, if either by casualty (if it so fall out) or by industry the stone be so fashioned, that those two opposite points be eminent or perspicuous therein: Potentially, if that either the stone be flat and but thin in the dimension of North and South though broad otherwise, for so shall the virtue of the stone be dispersed to the extreme parts thereof, in the edges round about; or if it have the two opposite points in any concavity, then will the stone show in the eminent border or edge of that concavity only a confused dull force, and in the concavity itself very little or nothing at all. That stone is well proportioned for touching which resembleth an oval form, and hath his due points in his ends, and is void of any bunch or concavity. For the general form of a stone being good, every concavity is a diminishing of his force, and every bunch is but a superfluous burden; Insomuch that myself have made experience of a stone that of substance was very good, and of weight was upon a three and twenty ounces, but of a disordered form, I therefore took away twelve ounces from him, and yet diminished not one jot of his force. And this did I in a stone that was all of like substance. But if it be one that is intermingled of divers substances (as many such there are and those easily discerned by their colour) you may sometimes take away three quarters and more of his substance without diminishing any thing at all of his virtue. For colours, most commonly the Ironlike is best: very black or whitish seldom proves good; grey, indifferent; the more white in any stone, so much the worse. There are certain that are of an iron colour, mingled with red, of which some be very good, some but indifferent. By three ways you may prove whether a Magnet be good or not; the one is, by taking up iron with the bare stone: The other by giving more or less virtue unto a knife, or any such thing to lift iron: The third if it will with good strength move a Magnetical needle a pretty good distance of, and readily alter the ends of the needle without touching of them, making the North South, and the South North: The two latter of these do never fail, but the first doth divers times. And very certain it is, that whatsoever stone doth most strongly impart his force unto a knife, or move a needle with quickness, the power of lifting up iron in such a one, will mightily be increased with a Cap. For this is generally the nature of all Magnets, that if there be 2. of different quantities, and equal strength in lifting up iron, the greater will give the stronger touch, and move a Magnetical needle farther of, although the lesser will take up as much iron, or somewhat more, than the greater. And again suppose there be a Magnet of a pound weight, that being fitly armed, will take up four pounds of iron, and not above, if you divide him into very small pieces, you shall find of them being orderly used that will lift up 20 times, yea 40 times his own weight and a great deal more, if they be made very small, as of three or four grains weight; And yet where the great one will give a touch unto a knife for to take up four ounces of iron, and will move a Magnetical needle three foot of; this little one will not give a touch unto a knife to take up a needle, nor move a Magnetical needle four inches of; that as a Magnet is diminished in substance (I mean a Magnet of a regular form) so doth he lose in his virtue of touching, and increaseth for his small quantity in lifting of iron, whereby it is manifest that these two properties go not always jointly together in the same proportion and degree. And here hence it is, that many seeing little Magnets artificially set in rings for to take up (for their quantity) a great piece of iron, do wrongfully imagine that the great one (whose particles they are) or any other great one, should do the like, namely to take up so many times their own weights. Also very often it is seen, that Magnets being of like form and weight, but of divers kinds, the one will take up more iron of himself without the cap, and yet the other give a far stronger touch; but then, if you do fit both of them accordingly with caps, he which gave the stronger touch, will take up more iron than the other. The principal force of the Loadstone well proportioned, passeth in a direct line, from the middle of his substance, being (as it were) a Centre, through his two ends or points, which are the imaginary lines of his chiefest force, from which Centre, there issue infinite others also through all parts of the Superficies of the stone, on either side, between the two extreme points and the middle, all which on either side of the middle, being of one nature and property in respect of their touch are exceedingly different in strength. For that still waxeth less and less, as it approacheth continually nearer and nearer the middle, where at length in the middle, between the two ends, it utterly fainteth and cometh to nothing. The Loadstone communicateth his property to the iron or steel that is touched with it, so far forth, as the iron, or steel, which is touched, hath ability to receive, and so that good skill in the touching be observed, steel is far better than iron, and receiveth a far stronger touch, and much more effectual. The purer steel, so much the better; and if it be iron, the purer likewise, the better, always regarding that both of them be very smooth, and clean, and have their due temper. The principal property in common use is the showing of North and South in the Horizon, with the appendents thereunto belonging, which is much more apparent, more strong, and more commodious in the iron and steel, that is touched, than it is in the stone itself, because the substance of them may be filled and cut away, and drawn into any form, that we like or list ourselves, which the substance of the stone will not permit. The Magnet is of such nature, that every piece broken of and separated from the whole, hath all the properties of the whole, the same several points of North and South, and ability also for the touch, like in kind, though not of equal power, according to the quantity and proportion of the piece, and the part of the stone that it is taken from, and this property in a meaner sort hath the touched needle and wyar of a Compass also.   

CHAP. FOUR By what means the chief points of any Magnet of what form soever may easily be found out.  
MAke a respective or declinatorie needle, of an inch or thereabouts in length and giving him his touch, fasten him by his Axis upon a little forked stick, or any such thing, that the needle may have free scope, then offer the stone near the needle, turning it round about, and immediately you shall see the North of the needle (as it is as yet commonly called, because it pointeth unto the North) point directly unto the true North end of the stone as soon as it cometh near unto it, and as you turn away the end of the stone the needle will point still somewhat towards it, till the South end of the stone approacheth, for than will the needle wheel about upon his Axis, and point directly with his South, and to the true South of the stone. But if you hold the needle near the stone, in such sort that it cannot turn about at liberty then the force of the stone may soon change the properties of the ends of the needle, that the one point which was North shall become South, and that the other which was South shall become North, yet the thing itself is easily discerned: For the Northerly end will always hang lower.  
And wheresoever the needle, being held nearer unto the stone doth stand parrallell unto it not inclining with either end, towards the stone there directly, under the middle of the needle, the North and South properties of the stone do divide and part themselves. This matter is much better performed, with a small narrow loadstone of half an inch (more or less) in length, having in the ends his due points of North and South and wrought over with silk of two colours from the middle to each end; as for example yellow and white; That part which pointeth to the North let it be wrought over with white, and the other with yellow. Then if you hang that in the middle by a fine silk thread, and apply it unto any other loadstone, the South end of the one will readily find out the North end of the other; and chose. In like manner, with this magnetical instrument you may see two pretty conclusions. The one if you touch a knife with the end of a forcible loadstone, whether it be North or South, and hang this wrought one by a silk thread in the middle, that it may hang freely, the one end will crave towards the point of the knife, and the other will not abide it. The other is, if you hang it end-long, with the true North end right over the North end of a forcible loadstone or with the South end over the South end of the other, you shall see that it will in no wise (being let down) come unto the North point of that loadstone, but will (contrary to philosophical principles that heavy things should tend directly downwards) by the means of the silk thread, swim or wheel about the end of the loadstone in the air: yea and lift itself somewhat upward, rather than perpendicularly light down upon it, yea this it will do although you place a plate of silver, latin, or any such thing, between the stone and itself.  

The second way.  
Thread a common sowing needle, and touch the point of it with the North end of any loadstone, then offer it unto that stone whose points you would find out, holding the needle by the thread about an inch therefrom, and in turning the stone about, you shall presently see the needle point unto the North end of this stone, and fly from the other end, when by your turning it cometh near. The contrary effect ensueth, if you touch the point of the Needle with the other end of the stone, wherein you may behold that ancient conceived, and of late years maintained error of the contrariety of Magnes and Theamedes to be nothing else but a contrary property of one and the self same Magnes.   

The third way.  
Break off the point of a sowing needle, half an inch long or longer (if the stone be good) but not above a quarter of an inch, (if it be a base stone) lay it upon the stone, and move it to and fro upon the Superficies thereof (being smooth) with the needles point forwards, and as it cometh near any of the two points of force, it will raise itself more and more: but being brought unto the point itself, it will stand there strait upright; If the stone be ragged this cannot well be practised, otherwise of all other it is the most certain way. Now whether it be your North or South end the effect will soon declare.   

The fourth way.  
Having an ordinary Dial with a magnetical needle, or a sailing compass, or any magnetical needle standing on a sharp pin, hold near thereunto the stone turning it in your hand, then will the north end of the needle (I mean the end that pointeth to the North) respect the true North point of the stone.   

The fifth way.  
Also if you touch a common sowing needle (the longer the better) and put ti through a little piece of cork, not bigger than may well bear it up, so that by the means thereof, it may swim in a basin of water, the same if you offer the stone unto it, will show the like effect. And here it is to be remembered, that none other way whatsoever will more readily or truly define the magnetical Meridian, than this of the needle with corcke in the water. And therefore as it is very requisite for many purposes that every traveler either by land or especially by sea should always have (if he may) an equinoctial Dial with him, so would I not wish that any of them should be without some sowing needles touched with a good stone which will both serve the proper uses of sowing without impairing their touch (for it is open air and rust that are the greatest enemies thereof) And at any time with a piece of corcke, or a dry stick in the water will show the magnetical meridian; a matter though mean and trivial in show, yet between while of so great importance that it may serve to save very many men's lives.   

A sixth way.  
Also if you prepare a little round Loadstone of a quarter of an inch diameter or there about (but it must be a very good one) having his two poles marked and fitted in such manner that it easily turn about in a little frame according unto this picture. The like also in his sort will come to pass, if you hang a small declinatorie Needle in a frame in this manner.  
Then by moving it in his frame all over the stone, the North pole of this will find the South of the other; And likewise will the South, the North of the great one; For it is not in outward show between one magnet and another, as it is between a magnet and a magnetical needle, the contrary ends of the magnet will covet in their motion to meet together, but the end of the needle which turneth North, will come unto the North of the stone: For in very truth it is the South point of the needle, even as the magnet itself being placed in a wooden dish in water will turn with his North end unto the South, and with his South end, dish and all, towards the North, as it is largely declared in the second Chapter of this book. The like effect will also follow if you hang as aforesaid a small magnet in the middle by a small silk thread, that it may freely turn without impediment according unto his own nature. But this property it will show quicker, or slower according unto the goodness of the substance, and fitness of the form. The best form for this purpose is the extended oval, having his poles precisely in his ends. If his poles be some pretty distance, the one end towards the East of the stone, and the other as much towards the West, this stone in his length will not point unto the magnetical North and South (as otherwise he would) but unto some other point of the Horizon; yea following this experiment in this sort, you may make him stand unto any point of the Compass: only you ought to abridge the stone in his length that he may come somewhat nearer unto a circular form, that so his diameter of North and South (being through the magnetisme of the earth, the cause of this motion) may be so much the longer in comparison of the Mass of the stone, and consequently more effectual. After the like manner you may so touch the wires of a Compass, that the Flower de luce of the fly, shall stand unto what point of the Horizon you please, although the Diameter of the wires do still remain fixed under the Flower de luce, and the South point of the Card.  
Finally to conclude this point with a magnetical delight, if you touch two sowing needles in a contrary sort, that is, the point of the one northerly and of the other Southerly, and set them with their corckes the one at the one side of a basin of water and the other at the other, you shall see them, as quickened with vital spirit, even so to move the one end towards the other, at the first fair and softly, but when they draw near they will rush together (as it were) with a kind of violence, the point of the one striking precisely at the point of the other, you must place the needle, whose point is touched for the North on the South side of of the basin, and the other on the other side: Otherwise the heads and not the points will run together, a thing far more worthy of admiration, than all the self movers of any Daedalus or Architas Tarentinus, and more strange to behold then the connexion of Iron rings combined by virtue magnetical, whereat S. Augustine so much, and that justly, did wonder.    

CHAP. V. The manner of capping both with single and double caps and the nature of them.  
THe stone being brought unto his perfect form you must have a mould made of Iron of the very same proportion in every respect and equal in all his dimensions, then setting the stone aside, let your workman frame & fashion his caps and fit them upon this mould as if it were the stone, thus shall you be sure to preserve your magnet from many dangers, very incident unto rude handling: And having so done you may set them on the stone itself, amending any small faults, without endangering the stone, either with bruisings, or knocks; For the thickness and largeness of the caps, there can be no general rule prescribed, but it must be left unto the trial and ingenious dexterity of the workman: as also for the handsome fastening either by soadering, or rivetting of them with latin plates to the Caps to keep them in their places firm and steady, according as you see in this picture of a stone, armed with single caps.  
Now therefore in this position, both ends of the Magnet being applied unto the two ends of the iron, these two contrary forces strive in this piece of iron, the North to repel the South, and the South the North: so that each force is driven nearer his own end, and becometh there so much the stronger than otherwise it would be. For proof whereof, take a little narrow square piece of iron, of the length of the capped stone, and joined in the midst with Copper after this sort:  
A. is supposed to be a long square, or a square-like piece of iron, in length fitting the two double caps of a Loadstone.  
B. a long square piece, the ends iron, the middle copper. C. hath a less space of copper, and D. least of all.  
If you apply the Loadstone unto A, he will hold A very strongly; but if you put any of the other three pieces under A, that it may touch any of them, he will not by any means lift it up. If you apply the Loadstone unto B, he will take it up very weakly, and C somewhat more strongly, but D strongest of all these three, yet not comparable to the strength wherewith he taketh up A. Again, although the Loadstone taketh up B but weakly, yet if you place B upon A, he will take them both very strongly; yea more, place B upon C, these two upon D, all three upon A, apply the Loadstone unto B, being the uppermost, and he will lift them all up very easily.  
The cause hereof is, when a Loadstone with his double cap is placed upon A, the force of both ends striving in that piece of iron paralel-wise unto the Axis of the stone, the North and South forces are driven more closely unto their proper ends. But in B, (because of the intermediate copper) there can be no such close driving of his forces into their proper ends, as was in A: and therefore the Loadstone lifteth up B, but only as if his two ends were two little loose pieces of iron, hanging in the air, and the intermediate copper a burden upon them. But placing B upon A, A in the manner (as it were) of a bridge, joineth the two ends together into their former combats, and the two ends of B, forasmuch as they are but (as it were) two loose pieces of iron hanging in the air, the two forces of the Loadstone North and South, distinctly and severally pass thorough them downwards into A, which it could not do, if it had been one entire piece of iron: and so all those four pieces, being placed one upon another, so that A be undermost, whether directly or sidewise, the Loadstone will easily lift them all up, and not otherwise.  
When a Loadstone lifteth up iron at one end only, the virtue of the stone is infused into the whole body downward of that iron, if it be not very long.  
But when by the means of the double caps, both ends do lift iron jointly together, he infuseth very small force downward into the body of the iron that it lifteth up for the forces of the both ends are so striving in a collateral line of the iron, parallel unto the Axis of the stone, that whereas a good Magnet lifting up at one end, will extend his virtue downwards twelve or fourteen inches, in applying both ends unto the iron, by the means of the double caps, he will not extend his force downward the distance of one inch, nor with any strength the distance of half an inch, as in this former example.  
Pliny in his natural history writeth, that Dinocrates that famous Architect builder of Alexandria, at Ptolemies commandment began to vault a Temple with Magnets, that there might seem to hang in the air the image of his sister Arsinoe, made of iron for that purpose: but both Dinocrates and Ptolemie dying in the mean space, that enterprise ceased. Neither indeed (if they both had lived) could it ever have come to pass by that means, by reason of two impossibilities: The one is, that by the force of the Lodestones, nothing can so hang in the air, but that it either must touch the stone itself, or some other intermediate substance between it and the stone, that barreth it from coming to the stone itself. For example, lay two or three needles upon a smooth table, put a silver or pewter plate upon them, and upon the plate a Loadstone, then lift up the plate aloft with the Loadstone lying still upon it, and you shall see the needles hanging indeed in the air endlong, and if you move the stone about the plate, following still underneath, but evermore touching the plate, which is the intermediate body, that keepeth them from coming to touch the stone, which otherwise by their natural inclination very speedily they would do. But as for that image of Arsinoe; how had it been possible for it to have touched at once, mediately or immediately, so great a number of Magnets, whereof the pretended vault must needs have consisted? The other is, that such a multitude of Magnets would nothing but confound the one the others forces, so that one of them alone being solitary and severed from his company, might show more force than all that insociable society could do, each one hindering the efficacy of the other. Much like a team of many horses, where every one drawing his sundry way, might soon with disordered stretching tire himself and his fellows, but never move the load one jot from the place. Insomuch as one (and possibly the worst) would do more good alone, where he might orderly and freely use his own strength, than he and all the many of them could do being joined together in vicinity of bodies, but extremely distracted through contrariety of courses.  
The only way to perform such a matter (if it were worth a doing) would be to prepare one mighty great Loadstone of excellent goodness: which having his due proportion, after an extended oval form, should be fitted with double caps, and so placed in the roof of a building, that his Axis be parallel to the Horizon: in this sort (out of all doubt) a fair large image might be held up very strongly by such a Magnet, let the stuff or substance thereof be whatsoever, (howbeit the lighter the better) so that there be fastened unto the uppermost part of the Image a small piece of iron accordingly prepared and placed for the two prominent ends of the double caps of the stone, to lay hold thereon. But enough hereof.  
In the capping of Magnets, this general rule is to be observed, that they ought to be made of the finest and softest iron, and not of steel: the weight also, which the Magnet taketh up, should be of the like iron, and not of steel, as aforesaid. For although steel retaineth at the least ten times as much virtue as iron, when it is once separated from the stone, can do; yet as long as there is any contiguity between the stone and them, he holdeth iron more strongly than steel. Both which differences in either of them by manifest experience are certain, and seem to proceed of notable fastness or closeness in the steel above the iron; by means whereof the magnetical virtue doth longer and more forcibly continue in that then in this: even as fire more mightily possesseth, and for a greater space abideth in stone, or any such firm or solid matter, then in wood, or straw, or the like thin and hollow substances: and therefore those compasse-makers, that make the wires of their flies for sailing compasses of mere iron, ought not by any means to be suffered: for to gain two pence in a compass (and scarcely that) they intolerably abuse those that travel by sea, to their great danger and mischief.   

CHAP. VI Of cementing and piecing of Lodestones.  
FOr your Simmon, do thus: Take the fine powder of a Loadstone, half so much powder of new brick made very small and subtle, one part of Burgundy pitch, half so much Rossen, a small portion of unwrought wax: mingle all these together very well upon a soft fire, and make the whole mass in little rolls. Now when you will cement a stone, do thus: heat the two pieces of the stone very hot, and likewise the simmon, than struck the places that you will solder, over with the simmon very thinly, and join them somewhat hard together, letting them so stand until they be cold, and you shall have it fully as strong, as if it were an entire stone of itself, and not to be severed but by great heat of fire. In piecing of the Lodestones, there must diligent heed be taken to the nature of the Loadstone in general, and also to those particular pieces which you would join together. The Loadstone in general (as it is showed before) that his force issueth (as it were) from a centre in the middle of the stone, to all the superficies thereof universally, but most strongly unto the Poles from the middle, one way the stone is all of a Northerly nature, and all of it Southerly the other way. For example.  
A. must be joined upon A, and B. upon B: but if you join the two so, that A. lighteth upon B, you mar the new Magnet, by confounding his forces. Notwithstanding if you like to join them in length only, not in thickness, than indeed must you combine B. and A, and not A. and A, nor B. and B, lest here also you incur the former inconvenience, of confusion of forces. Take another example: Suppose a Loadstone to be long and somewhat round, smaller at one end then at the other, the smaller end to be North signed with A, the other South signed with B: let this Magnet be divided long-ways into two equal parts, thorough both the Poles, A. and B.  
And let one of these halves be placed upon a piece of glass or a smooth Table; certain it is, that if you do offer to touch A, of this, with A, of the other, this A will turn away from that, which (the stone being entire) it did join with before: Or if you offer B, unto B, it will do the like. And no marvel, for in this case of touching A, with A, or B, with B: what else in effect do you, but attempt to join the two halves in length and that at like ends? A thing directly repugnant to the principles of Magnetical Philosophy. But let me admonish you, to put the rounder side of the stone downwards, next unto the glass, that it may turn the quicker: yet if the stone be excellent it will do the same also upon the flat side. Moreover if you place this two halves, the one upon the other precisely as they were at the first, they will agree very well: because they are as one, and the self-same Magnet. But if you place them the one swerving from the other, at either end, then will A, of the one, turn about unto B, of the other; because they are now as two several and divers Magnets. For the better conceiving hereof, you are to remember, that every part of a Loadstone (be it an half or any other) being once divided from the whole, is (as Schoolmen call it) Totum integrale, a whole Loadstone by itself, utterly diverse and estranged from that whole, whose part before it was, and therefore retaineth distinctly in itself, all the properties of a Loadstone, though not so strong, as the whole had when this was joined thereunto.  
In Lodestones there is a part truly said to be divided from the whole, when the points of that part, or ends, or Poles (and so, by necessary consequence, the Axis and Aequator, in which the universal frame of Magnetical power consisteth, have a position divers from the Poles or points of the whole. For this cause, in the last example the one half A: B: being supposed to serve from the other half B: A: at either end, must needs presently be divided from it, and now cannot be pars integri, but is of necessity Totum integrale, a several and absolute Magnet of itself, and so by an essential property common to all Magnets, coveteth with his point A, the contrary B: of that which is under it. Wherefore like as exact agreement is between two Mathematical figures when being applied together, the extremes of the one, do precisely fall upon the extremes of the other, each upon his correspondent extreme, and is made one therewith: even such is the perfect composition or setting together of the parts of a Magnetical body, and namely of those two equal parts before exemplified, you must so join one upon another, that the two extremes, or ends, be always of the same nature Northerly, or Southerly, in both parts: And that by due application of the parts, the two Northerly ends be united, and become one, as also the two Southerly ends after the same manner. But if these parts, being of equal length be joined longwise, the North of the one, unto the South of the other; those two ends that were (being now no ends but the just middle of one Magnet) have lost their properties which they had, when they were ends. For those properties, by this unition, are abolished: but their other ends still reserve their former and stronger virtues of North and South: And so, according unto Magnetical nature, one Magnet shall have but two Poles, the one North, the other South. Again, if you will piece two Lodestones together in thickness, the one of them being longer, than the other; than you must either cut the longer, that it may be fit in length, unto the shorter; or else piece the shorter in such sort as is afore described that he be equal in length to the longer, & what soever disorderly parts perhaps shall be in any of them, they may, even after they are cemented, very well be ground away. Also if there be holes or dents, with little pieces of Lodestones cemented (their points being observed) they may be filled up, without any manner of damage or deformity, no more than there had not been any such at all. And after this method you may (with labour and industry) of many Magnets, make one as huge, and of what form you please. And although the Magnets of this body, magnetically compact (as I have here showed) were never so many in number, yet the whole will have but two principal points, the one North, the other South, even as if it were one natural Loadstone: and all of them will contribute their forces, unto those two points; So that if there were twenty of them, being after this order cemented together into one body, the whole would have but two points, but if you will place them in a vault, according to a Mason's trade they will have 40 points, twenty North, and as many South, and will work the like effect in drawing iron, as (to use the former gross similitude) if a team of horses were set in their traces contrary the one to the other, the one to pull one way, the other another. As for the Turks Mahomet, hanging in the air with his iron chest it is a most gross untruth, and utterly impossible is it for any thing so to hang in the air by any Magnetical power, but that either it must touch the stone itself, or else some intermediate body, that hindereth it from coming to the stone (like as before I have showed) or else some stay below to keep it from ascending, as some small wire that may scantly be seen or perceived.   

CHAP. VII. Of the variation of the Magnetical Needle with the Appurtenances thereunto belonging.  
THE variation of the Magnetical Needle, being aptly fitted and placed upon his pin, is nothing else, but the swerving of the pointing thereof in the Horizon, from the meridian line there, the portion of the Horizon intercepted between the true Meridian line and this pointing, showeth of what quantity the variation is, and giveth it his name, to wit, which way it lieth, either Easterly, or Westerly, and it is observed by either end of the needle as you please.  
In times past men observed only by the North end of the needle, because they understood not that the Loadstone hath a South virtue, as well as a North; And therefore did touch their needles and wyars of their compasses always for the North only, leaving those ends of the wyars bare, that they might be refreshed with a new touch at any time afterwards: but the other ends they covered, not knowing that they were also apt to receive as forcible a virtue from the Loadstone for the South, as the other for the North. For the right understanding of the variation, with his necessary dependents, we must use the means of two circles: The one of them I will call the Magnetical Almicanter; The other is already known by the name of the Magnetical Meridian.  
This Magnetical Almicanter is a circle parallel unto the Horizon, whose centre is the vertical point, and is described by the distance between the vertical point, and the nearer Pole of the earth. The true Magnetical Pole is the pole of the earth; The magnetical respective Pole, or (which is all one) the Pole of the Magnetical Meridian, is a point in the Magnetical almicanter, distant Easterly or Westerly from the true pole as many degrees in that almicanter, as the variation of that place containeth in the Horizon, but always it is in the contrary part of the true Meridian, that is, if the variation of the South point of the needle be Easterly the respective pole is Westerly: but if you observe with the North end of the needle, the respective pole and the variation are both one way in all our Northern Climates. If the variation of the South point of the needle be Westerly, then is the respective pole so many degrees in the said almicanter Easterly, and therefore always of the same height with the true pole above the Horizon. For since all great Circles of the globe do necessarily cut one another in two points into two equal parts: these two therefore must needs do even so in the Zenith and Nadir, by their very definitions; So that these two points (the Zenith and Nadir) are always alike common unto them both, aswell unto the true, as unto the Magnetical Meridian.  
Wherehence it followeth necessarily, that always the one half of the magnetical meridian is on the eastside, and the other on the West side of the true meridian, the common Zenith and Nadir evermore keeping their equal distances from the Poles▪ of the one of them, as they do from the other. For example: Suppose the common Zenith to be in the Aequator, you sailing East or West, as long as there is no variation, there is no magnetical meridian, there are no magnetical Poles, but those of the world. But as soon as, sailing still under the line you do find a variation it is the magnetical meridian, that by his swerving from the true meridian of the world in the Horizon showeth the quantity of the variation, and giveth it also the denomination of Easterly or Westerly, and his axis is the line of variation. But supposing the common Zenith, to be in any parallel, between the Aequator and the Pole, then is it not the axis, but some other Diameter of the magnetical meridian, which showeth the variation in the Horizon; And the magnetical meridian evermore cutteth just so many degrees of the magnetical almicanter on the one side of the true meridian, as the same Magnetical Pole is distant in the same almicanter, on the other side of the true Meridian from the Pole of the World. And this is to be understood in correspondent manner, as well of the South Hemisphere, as of the North.  
The respective Magnetical meridian (where any variation is) is a circle that passeth by the vertical point and the Nadir, and both the respective Poles, crossing the Horizon at right angles in the points of variation, of which circle the line of variation is a Diameter, but where there is no variation the true and Magnetical meridian are both one & the self same, and so in like manner are their Diameters. Those circles and poles are termed respective because that in every place where any variation is, the Magnetical needle doth respect them, as well in the property of direction, as in that of declination, or inclination. For thus also very well it may be termed. By the property of direction, I do mean, with Doctor Gilbert, the horizontal motion of the Magnetical needle: By the declination, or inclination, I mean the descending, and (as it were) the sinking motion of the need under the Horizon, in his proper Azimath, or Magnetical meridian; But if there be no variation, the needle always pointeth unto the true Meridian of the earth, and towards the Poles thereof, in both those properties. The true Poles of the earth (which are those two points equally distant from each part of the equinoctial of the earth are always the self same. The respective Poles alter with every Horizon, where there is any variation, but never out of the aforenamed almicanter of that place. The causes of the differences of the respective Poles and Meridian's from the true Poles and meridians, and so of all variations, are only two; The chief and most general is the vastness of the Ocean sea, by moistness whereof the Magnetical collateral force of so much earth as it covereth, is much hindered and dulled. And by that means the next great Continent hath more power over the correspondent end of the Magnetical needle, then otherwise it could have if all were alike one entire Continent: and therefore causeth the directive property of the needle somewhat to serve towards that way, which is that, which we call variation; but yet the vastness of the Ocean doth not hinder the declination of the Magnetical needle; Because his hangings consisteth but in length and breadth, and not in depth. For although in comparison of a pond or river, the sea is said to be of a wonderful depth, yet if this depth be compared with a Semidiameter of the earth, it beareth a very exceeding small proportion, nothing at all to hinder the mighty magnetical declinatory force of the whole earth; For the greatest depth that ever any man of skill esteemed it at, was not above two English mile, at the uttermost, when as daily experience maketh it manifest, that a great Continent will show his Magnetical collateral force, by causing a variation, above two hundred miles of from the place, and therefore Doctor hearts fear in that point I take to be needless, supposing a variation of declination. The second cause of variation, is any great mountainous region not far of, when a man is in some great Latitude towards either of the Poles: if that mountainous region lie Easterly or Westerly from you, it will cause the needle somewhat to serve that way. But variations of this sort are of small continuance, and in sailing subject unto sudden alterations, yea many times quite contrary from Westerly to Easterly & afterwards back again within short space: as our first famous Pilot Steven Burrough found by his experience in the discovery of the Scythian sea-coast between the north Cape of Finmarke and Vaygates. The reason whereof ought heedfully to be regarded which is that the Magnetical force of the whole earth, doth (as in all Magnets) show itself most strongly in the two Poles thereof, and in those places which are near unto them: but always it must be remembered, that all the force they have doth issue out of the whole terrestrial body, as it doth likewise in all Magnets out of the body of the Magnet: and therefore in any part of the superficies of the whole terrestrial body, it is impossible that any variation be above 90. degrees, because the virtue of the whole can never be overswaied by the imperfection of a part, and especially of so small a part as any one portion of the Ocean is in his very superficies, in respect of the body of the whole earth: yea I am thoroughly persuaded, that there never was nor ever will be any variation, by any good observation found for to be so much as ninety; neither any show of so great variation any where, except it be very near unto either of the Poles, where there is small credit to be given to the observing of any variation: for the variation being (as aforesaid) the difference of the pointing of the magnetical Needle in the Horizon from the true Meridian, for as much as in places near the Pole, there is no manner of certainty of either of these, it is not possible to find the variation, if there be any. The reason whereof is this, no man may travel those Seas, but whiles the Sun abideth on that side of the Aequator, whereby they have continual day, and by that means are secluded from any help of the stars, neither if they might be seen, would they bring any great help. For the difference of height in many hours is so small, that by a very large instrument a diligent observer with great pains will hardly find the Meridian Line, all the Meridian's themselves coming so near one to another, and meeting in the Pole, and their Horizon being in a manner parallel unto the equinoctial. And as for the horizontal magnetical Needles, to show their pointing in the Horizon as they were wont to do, they coming into this climate may say, Fuimus Troes. Their direction is as it were giddy and uncertain, and when their centre cometh unto the Pole itself, it is quite vanished away; for from thence all the points of the Horizon are only South, if it be at the North Pole, and North from the South Pole, and therefore in that place the instrument of declination is far more sure than the horizontal Compass. And as in the Poles themselves there is no direction at all, so of necessity near unto them it must be a very confused direction. Those two places, that are called the Poles, have no strength of themselves (as aforesaid) but as it is contributed unto them of the whole. As in a Magnet, if you break off a piece of the contrary end, the end that is left will be according unto that proportion diminished in his strength, and the polar piece, that was broken off (be it never so little) will have two poles as well as the great: so that the two parts will have four Poles, two of them North, and two South. Put this little piece that was broken off, in his place again, and then each piece will lose one of his Poles in the same very instant, and the whole will have but two Poles, the one North, the other South, as at the first. Again, if you cut off a piece of one side of a Loadstone, that is brought into a round or an oval form, having his Poles marked in their due places at each end, presently both end will be abridged of part of the force they had, and the Poles themselves will be removed unto the other side, from the places that were marked, and those marks will stand but for idle ciphers in comparison of that they were before. Again, take a Magnet of a round or an extended oval form, (I do still exemplify in these, because they are of all others, as I have often admonished, for all magnetical proofs the most excellent forms) and set marks on the two Poles, take a fine needle, or any strait small wire, and set it on the equinoctial, (I mean thereby the middle between the two ends of the stone) then will it point directly towards each Pole, if the stone be sound without any flaws, or any other gross substance (as may be) intermingled with it: and if you thrust this needle towards either end, according unto his own direction he will trace you a circle right over both of these marked Poles, which is the true Meridian of the stone. But if this stone hath in either of the sides any imperfection, when the needle cometh unto the edge or brink thereof, it will serve somewhat towards the sounder side, and will point to neither of the true Poles. And if a circle be drawn according to his pointing, as he standeth still in that place, this shall be a respective Meridian of that stone, proper unto that place: and the Poles. the respective Poles, differing from the true Meridian of the stone and his Poles. Now if you thrust the needle further towards the end, upon the brink of this imperfection, it will not point (as before) but either further off, or nearer towards the true Poles▪ and will give his direction for a new respective Meridian; and new respective Poles, And in such manner infinitely, if you place the needle in the middle of this imperfection, equally distant from the sound parts, then will it indeed point towards the true Poles of the stone, And the Consequence hereof is the main reason, that towards the midst of the Ocean; and likewise of any great continent there is no variation. Thus may you especially in a round Loadstone (as in a lively example) see the true causes of all the variations that are in the whole world, reckoning as much space as the Ocean covereth, to be some imperfection in the body of the whole, in respect of the horizontal motion of the Compass. For the evidence of the truth hereof, let a man examine generally the variations of our most expert Navigators (Although by reason of their diversities of the sets of their Compasses, and unfitness and unapt handling of their instruments, they very seldom times agree among themselves) observed in the Atlantic Ocean, from the Aequator unto the parts of Norway, all along the East coast from the Meridian of the Azores: And in like manner from the Aequator to the parts of Newfoundland and upwards, all along the Western Coast from the Azores, as far North, as hereunto hath been discovered, and he shall find the ordinary practice to testify the truth hereof, as also after the same sort from the Aequator Southward unto the straits of Magellan, and all along the backside of America in the South Sea: and on the East Coast unto the Cape of Bona speranza, and he shall perceive the like agreement: But in sailing from the Cape of Bona speranza, farther Eastward, that sometime they do find it otherwise, the cause is the different manner of the situation of the South, as yet undiscovered Continent. And whereas in the midst of the Atlantic Ocean, about 30. leagues Westwards from the Azores, they find no variation at all, no marvel thereof: For it is about the middle distance between the two great Continents of America and ours.  
Wherefore the round Loadstone is significantly termed by Doct. Gilbert Terrella, that is, a little, or rather a very little Earth: For it representeth in an exceeding small model (as it were) the admirable properties magnetical of the huge Globe of the earth. Herein also we may behold the reason why, the magnetical needle varieth least in the equinoctial, and most towards the Pole, and in the Poles themselves giveth no direction at all: For proof hereof, take a needle and place it upon the equinoctial of the stone, there you shall see him stand equally balanced and very strongly, so that if you turn him from his direction, as soon as you let him go, he will presently turn unto it again. The reason is, because each Pole doth equally strengthen his correspondent end of the needle. Move this needle toward either of the Poles, then doth the nearer Pole strengthen his end of the needle; but the farther (because of the distance) cannot do the like unto his, but very weakly, and this needle will not stand any more equally balanced (as it did in the equinoctial) but that end next the Pole will couch down, and the other will rise up. For on the North side of the Aequator, the true South end is predominant, and on the other the North end hath the mastery. And that this is also in the earth itself, all our late travelers confirm unto us by their daily experience, and all the very Artisans and needlediall-makers in the world must needs be daily witnesses of it. As for example: Let any workman in our Climate make a needle for a dial, when he hath fitted it and placed it on the pin, that it may stand thereon equally balanced and parallel to the Horizon touch it with the Magnet, then presently that which pointeth towards the North will hang down (yea, although you touch only with the South end) and will not stand, as before the touch equally balanced and parallel to the Horizon: except you cut or file somewhat from that end, that hangeth down; or else add a piece of wax or some other thing unto the other end of the needle to counterpoise it, and make it stand equidistant as it did at the first setting on: and this is a thing very certain, that this Northerly descent of the needle, will be more or less in all places of Northerly Latitude: In the greater Latitude the more, and in the lesser Latitude the less. But if any traveler carry this needle beyond the Aequator in the like Latitude Southerly, that end which tendeth downwards in the Northerly, will rise up in the Southerly, and the other sink down, even as much: and the nearer you travail towards either Pole, the more, that end which pointeth towards the Pole, will tend downwards: This is most certain in every Diall-needle: but a great deal more apparent it is in a long one, than it is in a short one. We cannot find that the property of direction by the Magnetical needle hath been vulgarly practised (for sailing) much above 200. years. And as for the property of declination under the Horizon, thereby to show the Latitude by the Instrument thereunto belonging, it is as yet a very newcome guest into the world, borne and bred with us in England, and (except it be in exceeding few men's hands) not yet in use, much less come unto his perfection. But this it not to be marveled at: because it is scantly sixteen years old; neither is it to be wondered if any Critical fellows do contemn and deride it. Forasmuch as either their want of knowledge, or of patience, will not give them leave truly to consider of it. But what Navigator, or rather Nugator soever contemneth it, shall be sure to repent it if ever he come to his right wits to consider what it is that he hath contemned. And although the needles for direction and declination do differ much in their shapes, each from other; yet the properties are both one and the self same. For the needles for direction do decline (as aforesaid) as far as the unfitness of their form and placing will permit them: and the declining needle will not work, but only in his Magnetical Meridian, which himself will find out, if you turn the Instrument about, until the needle show his least declination under the Horizon, and there do play up and down & stop in the end in the same place again. But if you would have a needle fitted to show both properties, do thus, cause a needle to be made a bout six inches long, even and smooth, saving that he must be a little bigger in the middle, then instead of an Axis (which declinatory needles have) let him have a small hole drilled precisely in the midst, and this hole being very small, let it be somewhat wider outwards on each side then in the midst, (which our workmen call sinckboared) where it must be left very sharp, even almost as the edge of a knife: put through this hole a small verginall latin wiar, and fit the needle so that it hang precisely even upon this wiar, instead of an axle-tree: then touch him with the Loadstone, and you shall presently see the end that should point towards the North, decline or bend down to his due place of declination, if he be placed in the Magnetical Meridian; set a little piece of wax or any other thing upon the contrary part for a counterpoise that the needle may stand parallel with the Horizon, then if it stand at right angles with that verginall wiar, it is certainly in the Magnetical Meridian: otherwise it will never stand at right angles, but will make his sharper angle always towards the Magnetical Meridian. So that hanging in this counterpoise if you turn about the wiar until the needle do make right Angles with it, then doth the needle by his directive virtue point unto the Magnetical Meridian line. Take off the counterpoise, than it showeth the declination for that place, and by consequent the Latitude, if you in that manner place him in the Instrument of declination; so that one and the self same needle in the same place only, by taking off, and putting on a little piece of wax, showeth plainly both those properties of directions and declinations, as in like manner every inclinatory needle will do, if the points of his Axis be sharp, and held in his box parallel unto the Horizon, he will show both those properties of direction and declination: A fine piece of corcke or leather, or any tough substance may serve this needle for a counterpoise in all Latitudes by thrusting it towards the centre in less Latitudes, and towards the end in the greater, and I think it not impossible, but that a skilful Geometrician may so graduate the one half of such a needle, that it alone with his counterpoise, may be a means to give a probable conjecture for the Latitude of any place whatsoever.   

CHAP. VIII. A discovery of errors committed in making and touching Magnetical Needles and Wyars of sailing Compasses, with an advise for the true and right making and touching of them.  
FIrst the wyars that are commonly made both with us, and in foreign countries, are of so base and drossy iron, not apt nor sufficient to receive the tenth part of the virtue that fine steel wyar could do.  
Secondly, the ends of the wiars be for the most part not filled smooth nor fitted even together upon the Axis of the fly; By means whereof the touch of the stone is more dully received, and the standing of the fly, the more uncertain, the magnetical force not being in the true axis thereof.  
The reason here of is this, the Magnet giveth his force (Secundum mensuram recipientis) according to the capacity of that which receiveth it, and that ever more after his own nature, which is to have his force strong in his ends, and none at all in the middle, if you touch the blade from the middle, with either end of the stone, the other end of the haft will immediate receive and show the contrary quality: even so also will it come to pass, if you make proof with any Magnetical needle, although that his force will be faint and weak in comparison of the other. And in your touching you must observe, that in pressing with the stone from the middle of the needle unto the end, as you bring your hand backward to iterate the touch, you must lift your hand somewhat high, and not bring it backward, close to the needle. For that would diminish the strength of the touch. But if that end of the needle be also touched with the other end of the stone, in manner as above I have rehearsed, then shall he at each end be a great deal the more strong, and the contrary fainter forces shall recoil and settle in the middle of the needle, where they can nothing at all disturb the motion thereof.   

CHAP. IX. Of the touching with a Laadstone capped and without the cap.  
BY capping, is meant the placing of two pieces of iron handsomely fitted and fastened upon the two points of the stone, for iron for this purpose is better than steel. And likewise concerning the the weight that is to be lifted up, it is better to be made of soft iron then of steel, and the stone will lift more thereof, as long as there is contiguity: but if if the iron and steel be separated from the contiguity of the stone, the steel will always carry at the least ten times more virtue than the iron, as is before mentioned. Now whether it were best to touch the wires with a Magnet being thus capped, or with the bare stone itself, some there be that make a question. I have been told by one of great skill and practise, that he found by experience, the Compass touched with a capped stone, not to receive his force so well, as the other, and the party coming unto me, when he was to undertake a long voyage, to have his compass touched, requested me in any wise to do it with the bare stone: But yet I think it were good, that this be confirmed by more than one man's experience, before it be believed, because by some error he might possibly mistake the matter. Sure I am that the capped stone giveth somewhat more virtue in his touch, and by all experience that I have made, I find it to continue as firmly and as long. Howbeit I refer me herein to the ttiall of others also. A man may therefore touch the wiars first with the bare stone, & then with the same being capped, or chose to be surer of the greater force, and yet if any shall imagine the difference of the strength of the touch, to be according to the taking up of iron with the cap or without it, he is very greatly deceived. For I have often tried them both, but never could see the touching strength in the needle to be increased half a quarter more with the cap then without it; whereas I have always (especially if the stone were very good) found that the stone will lift at the least ten times as much iron: yea, a great deal more, (and sometimes twenty times) with the cap (if it be artificially fitted) than he is able to do without it.  
Some, who would seem to be of great skill, have imagined, that the best way to add strength to a needle, is with a hammer to give some forcible strokes to one point of the stone, thereby causing litragges (as it were) or beard, to hang down from it, & that the needle in his touching, taking some part of that with him, should have the stronger touch. But they that so suppose deceive themselves therein: for that beard is nothing else, but the fine dust of the stone, hanging together by virtue thereof: which being separated from the stone (although it were a right good one) is not able any whit at all to turn a needle of itself. The trial is soon made by this means, let them take of that beard from the stone with a stick, and lay it upon the end of a needle not touched, and they shall find in it no force at all, nay it is a hurt unto the needle. For it giveth a superfluous burden for a small time, and cannot but encumber his action, by reason that every one of those little parcels of dust (though beaten out at one end) hath also for his small quantity both a North and South virtue. And therefore marreth as much as it maketh at either end of the needle. The proof hereof is manifest, if you put off that dust or beard upon a paper, and hold a Magnet therunder, for as you turn towards the paper the North or South of the stone, so will every one of those particles in like sort turn itself, showing thereby a double nature.   

CHAP. X. Of the fashioning of the compass needle.  
THe Compass needle, being the most admirable and useful instrument of the whole world, is both amongst ours and other nations for the most part, so bungerly and absurdly contrived, as nothing more. And therefore entreating now of the nature and use of the Magnet. I have thought good, also, to employ my best endeavour, to advance this noblle instrument towards his highest perfection, being the principal thing, by which the worthy effect of the Magnet, is made most profitable unto mankind. Herein five things are to be considered, the substance that it is made of, the form, the weight, the capitle, and the pin it standeth upon: The substance in any wise aught to be pure steel, and not iron. For most assuredly steel will take at the least ten times more virtue than iron can do, but especially if it hath his right temper. And that is this: Heat it in the fire until it be passed red hot, that it be whitish hot and qnench it in cold water suddenly: So is it brickle in a manner as glass itself, and is at that time incapable of the virtue of the Loadstone. Then must you, laying it upon a plain table, warily rub with fine sand all the black colour from it, if before you put it into the fire, you anoint it with soap, it will scale white of itself, than heat a bar of iron well near red hot, and holding one end of the needle with a small pair of tongues, lay the other end upon the hot bar, and presently you shall see that end turn from white to a yellowish, and after to a bluish colour, then take that end with your tongues, and do thlike unto the other, thrusting it forward upon the bar until the colour of the whole needle become bluish: then throw it on a table, and let cool of itself: and so is he of the excellentest temper, and most capable to receive the greatest power from the Magnet. If this seem too curious especially for some fashions of needles, then use but the hammer hardening (as workmen call it) which is well near as good. As concerning the form, divers men are of divers minds, some use a kind of square one, others a loop (I mean an extended oval form) and this is most common. But now a days, a narrow strait place (being somewhat broader in the middle) is in great request: Of these three I hold the loop or oval form (if it be well made) to be the best, which is, that if it be of steel, his ends be wielded together, having a latin narrow plate, issuing from the capitle unto the middle of the two sides of the loop, and there riveted, and rivetting, if it be handsomely shouldered in by the workman, is better than soadering: because, having fitted the latin plate bearing the capitle unto the loop, you may first put your loop into his temper, and then rivet this unto him afterwards, which otherwise would be marred in the fire, and the wide loop is better than the narrow or the strait plate, and that for two reasons. The one is, hecause, as in a Magnet itself, the force that is in the whole body, showeth itself most strongly in his two poles, even so this being a Magnetical body, doth the like in his ends which are his poles: and the sides of a wide compassed loop (being longer, then of a narrower) of the same length, in the Axis, must needs contain so much the more virtue; the other reason is, because it supposeth the fly in his circular motion more equally balanced then the other: and therefore were it not for some other inconveniences, a true circle were best of all, which is that except you mark the two places, that you would have for the North and Souch, very curiously, you shall never give him the right touch: yea, very exceeding hardly, although you do mark them; and also the latin stay, that holdeth the capitle, would be exceeding long and a superfluous burden: but the very best form of all (as I take it) in all respects is this, a true circle, having his Axis going out beyond the circle, at each end narrow and narrower, unto a reasonable sharp point, and being pure steel as the circle itself is, hane in the midst, a convenient receptacle to place the capitle in.  
This circle must have four very small holes drilled through it, equally distant each from other, for the four cardinal points, and in both the two points, that issue without the circle, being for North and South of equal distance between the circle and the end of the point two more, if it be a large one, otherwise one is enough, according unto this picture following. And this needle is most fit to be used for the observation of the variation alone without any fly, as I will show at the latter end of this Treatise.  
Whensoever you will set this needle unto the fly, you must put the capitle through the centre of the fly very precisely, and placing the points of the Diameter where you will have them, thrust little small pins through the upper face of the fly, and those small holes in the needle, the heads of the pings will show you (if the fly be larger than your needle) at what point your needle standeth, and bowing the body of your pings (being thrust through those little holes) close to the card below, will keep it steady at that place, and from warping also. And so four pins at the four cardinal points will serve the turn.  
Again, if you please for to place this needle upon the upper face of the Card according unto Stevinius. it is no more but to have the capitle loose, thrust through the centre in the bottom of the fly, and the needle placed and fastened on the top, or upper face of the card.  
But if you will have a Magnetical needle to serve only for one size of a fly, the best way is, instead of the two pings in the ends of the Axis, to have a couple of little half staples and a Flower de luce on one of them, as you see in the loop, riveted there. That in turning about the needle, they may still keep the fly close unto it, and so fasten it with a screw upon the capitle wheresoever you please.  
As for his weight it must be according unto his largeness, and the weight is one principal cause, that very large compasses are unprofitable. For the weight of the large card, and heavy needle, pressing upon the pin, will cause the motion of the fly to be dull and uncertain, and therefore let the pasteboard be no heavier than you must needs; and for the size of six inches Diameter of your pasteboard, and a needle of that length. I know that a needle of half an ounce weight, and half a quartern at the uttermost (if a good workman have it in hand) will be very fully sufficient, of what form soever.  
The capitle aught to be latin, and hammer hardened, well and truly bored, not too shallow, but of a good convenient depth and wideness at the bottom, fitting the pin it standeth upon at the top. The pin ought to be either of latin, or copper, and not of iron or steel, as some use; for they are very subject to rust: and the steel, especially by long use, will wear a little hole in the top of the capitle, and by that means the Compass becometh dull, and they hardly (if ever) will find the reason of it; for the hole will be passing small, and entering an exceeding little way in, and yet disturbeth all. Moreover, in any wise there must be always an especial diligent care had of fitness between the capitle and the pin. Oteerwise, all things else appertaining unto the compass are nothing worth. This pin must be very firmly fixed in the just centre of the box, and the bottom marked, that whensoever you take it off to sharpen the pin (which use will make blunt) you may set him in the same place again.  
As I have said that in a Magnet itself, the virtue is in the whole body, and showeth itself most forcible in his poles; even so likewise our Compasse-needle, being a Magnetical body, showeth his force in his ends, which are his poles, although that force doth proceed out of the whole body of the Needle. Which now I thought good to make apparent by an evident demonstration: I caused my workman to make a needle of a Loop fashion, 8. inches long, or oval form in all respects fitted to be set unto a fly, saving that there was but one inch or a little more at each end of steel, all the intermediate part between the two ends, being of brass: These two ends I did touch with the North and South ends of a very good Magnet: And whereas in a true Magnetical Needle, I should have had but two points, the one North and the other South, this Mongrel yielded me six, the two ends adjoining unto the brass of contrary natures unto the sharp points, & would no more do the office of a Magnetical needle than a wooden stick, because the virtue was not in the whole, and so communicated unto the two ends, but each end was a total of himself, being separated, and (as it were) divorced, the one from all community with the other by that intermediate brass: the which being taken away, and the two forks joined together for that length, presently they became one perfect true Magnetical Needle, and the virtue of those four confused points, which ere while was was lost in the forks, will presently be found in the two sharp ends, and now his natural seats: Both these ends of steel were fastened unto the brass, and then that needle had no Magnetical motion; but being taken off, and joined together, they presently (without any further touching of them) became a true Magnetical Needle.  
To conclude this chapter of the Compasse-needle, The needle that is still working upon his pin continually will keep his force better, then that which is otherwise laid up, although there be no doubt of the other, for a man's whole age, or longer, if it be of good metal, and kept from open air and rust, and from too near vicinity of iron, but especially of any Loadstone. No better keeping from rust, then by varnishing him, although it be but with a drop or two of Linseed oil alone; the needle that is continually upon his pin, is still strengthened by the Magnetical power of the earth, setting himself always towards the Poles thereof (which the other cannot do) and needeth only to have his pin sharpened now and then: The which of all the faults incident unto the Compass, is most easily and safely amended. And yet, if it be not very well looked unto, it disturbeth all the operation of the Compass more than any other. And divers wrong themselves in being too busy in often touching of their Compasses, the fault being in this which no touching can amend.   

CHAP. XI. A Sailing Compass fitted for observing at Sea the variation, amplitude of either sun or stars, capes or trending, etc.  
I Have thought good to conclude this short Treatise of Magnetical advertisements, with a little additament unto the ordinary sailing Compass, fitting him thereby to be answerable unto the title here prefixed, as also with a comparison of the several uses, of the horizontal and inclinatory needles: Let the glass of the inner box of the Compass be of good thickness and strength (but yet clear) and even, those that come from Venice for looking glasses before the foil be set on are the best, if a man may have them large enough. Let this glass be very well fitted unto the box, and simmond underneath upon the shouldering that beareth up the glass, with a mixture of wax, turpentine, salad oil and rosin mingled together: or with any other simmon as you shall think good, above upon the glass let there be a ring of thin pasteboard, of the breadth of the shouldering underneath, in like manner simmoned on: then must you have a circle of latin about the breadth of the pasteboard ring, of convenient thickness for strength: which must be divided into degrees: This circle must have a plate of latten, of half an inch broad or broader, according unto the largeness of the circle for strength, that must cross over the midst of the circle, cut out of the same place with the circle, or else so adered with silver so ader: this must have a line all along the midst of it, and a little loop at each end cut through the two ends of the loops being precisely in that line. Last of all, you must have a movable ruler with two long folding sights, of about the length of the Semidiameter of the circle in breadth about half an inch: the one of them must have a slit through the length thereof, of about a quarter of an inch broad, as you shall think convenient, and two little holes, the one in the top, and the other in the bottom, just in the middle of it, to fasten a string, having a very little bead to slide up and down upon it. And this sight must be of the thicker stuff than the other. For otherwise, because of that which is cut out, it would be overpaised by the other, and so the box would serve towards the other; and the sights must each of them have a little notch in the midst of the top of them: this ruler must be fastened (but yet so that he may turn about) in the middle of the cross plate most precisely in the centre of the circle, his ends cut, that he may show the Fiducial line in the divisions of the circle, the other sight needeth to be but a a plain plate, having a line in the middle, from the top to the bottom. The description followeth, being the very same in substance with that, which in the Navigators Supply, I call the Compass of variation; although all things easier performed with this, then with that,  

The Picture.   

The Uses.  
The Compass being thus fitted, place the circular needle described in the sixth chapter, upon his pin alone without any fly. For being disburdened of the card, he will show his virtue the more strongly, and being of that for me he will balance himself sufficiently.  
Place the circle upon the glass and pasteboard, in such sort that you may turn the circle round about, very close and even, within the brim of the box.  
When you will set the same unto the Compass, turn the circle about, until through the Loops of the middle stay or plate, you see the Axis of the needle right under the Fiducial line of the middle stay, then holding the circle so, turn the movable ruler with the stringed sight towards the sun, until the shadow of the string fall upon the fiducial line of the movable ruler, for than doth the end of the ruler, among the degrees, show the true place or Azimuth of the sun from the Magnetical Meridian, so that two observations, the one in the forenoon, the other in the afternoon, thus made, with the several heights of the Sun, being one and the very same, hall the differences of those places of the sun, from the Magnetical needle is the variation.  
As for example, if the ends of the ruler did cut forty in the forenoon, and fifty in the afternoon, the difference is then, the half thereof five: so much must the variation be Westward.  
If a man have no exact instrument to take the height of the sun, he may make some reasonable shift, by setting the little bead towards the top of the string, that it may in the forenoon cast a shadow upon the Fiducial line of the ruler; and marking that place with any thing (as ink or black lead) in the afternoon attend, until the shadow of the bead (the bead remaining still where it was) fall upon that place. For than shall you have that same height, if you will take the amplitude of the suns rising or setting, set the circle, and turn the ruler, as before, until the shadow of the string do fall upon the middle line of the other sight. Then doth the end of the ruler show, how far the sun riseth or setteth from the magnetical Meridian.  
When you will take the amplitude of the rising or setting of any star, you must use the help of another, to hold the circle over the needle (as before) and so you turning the ruler, until you see the star in his rising or setting, through the two Notches on the tops of the sights, then doth the end of the ruler show your desire, The like is to be done in observing any cape, or the trending of any land for the dedescription of any Coast.    

CHAP. XII. A comparison of the several uses of the horizontal and inclinatory Magnetical Needles.  
THe horizontal and inclinatory motions of Magnetical needles are both of them but one and the self same effect of the Magnet or Loadstone, the making of the horizontal or Diall-needle, is among our artificers very well known and trivial, only they are to be put in mind that they do always make them of pure steel and not of iron. But as for the making of the inclinatory needles, it is a very curious piece of work: It must be of pure steel, and in his right temper, the needle and his axis must be at right angles the one with the other, and must be so hanged on the two ends of his axis that he be very pliant for his motion, and that (before he have his touch) he be so equally balanced, that the one end be not one jot heavier than the other, for if it be, all the rest is in vain.  
When you will use the inclinatory instrument, thus you must do, hanging him by his little ring, turn him about until he make his least declination (or inclination) under the Horizon of the instrument: for than is he just in his Magnetical Meridian, and there showeth his due point, the which otherwise he can never do. But here I must admonish you of two very great errors published in the contriving of this noble instrument. The one is, that he would have a little box with an horizontal Needle fastened unto the bottom of the inclinatory instrument: for to direct the instrument unto the Magnetical Meridian: and by his picture of the Instrument, the distance should be but a little more than an inch, where it is impossible but that the one needle must needs disturb the other, so that neither of them can show aright, yea, although they were six inches asunder, and more, where the little box will give little direction for that purpose? and beside that, it is altogether unnecessary, because the instrument will find the Magnetical Meridian, by the least declination of the needle (as is showed before) under the Horizon, without the help of any other. The other error is this, that he would have that end of the needle prepared to hang towards the North, to be framed somewhat higher than the other, as is usual in horizontal needles: what workman soever observeth this direction, I will assure him, that he shall lose his labour, and assoon he may wash a Blacke-moore white, as to make such a needle serve that turn. The reason is, because it is only the magnetical virtue that worketh this effect, the which overwaight, in either end of the needle (in this motion) doth utterly overthrow.  
For horizontal needles in our Northern Climates, it is necessary: but for inclinatory needles, it is utterly untrue in all Climates of the whole world wheresoever. The motion of the horizontal needle, is naturally stronger than the inclinatory for two causes, The one is because his motion is only sidewaies, the which is easier for the Magnetical motion to work in, then that which is up and down, and that there is no difference which way you place the box wherein he standeth, so that it be parallel unto the Horizon; whereas the inclinatory motion is in a vertical circle up and down, and must stand only in his Magnetical Meridian to perform his office. The other cause is because of the diversity of their placing in their boxes: for the Horizontal needle standeth more fitter for his motion, being placed with his capitle upon the point of his sharp pin, than the inclinatory can do, being placed upon the two ends of his axis, although never so near the points: But yet he will do very well, if he be rightly fitted: And for Navigation under either Pole (if there be any passage that way) it is the only Instrument of the world. For where the horizontal needle (or compass) faileth, he is strongest, for the nearer the Pole, the stronger he is in his Motion, chose, it is with the horizontal needle or compass, for he is strongest at the equinoctial, and of no force under the Pole.  
The reason whereof is this, under the equinoctial the horizontal needle standeth parallel unto the Axis of the earth, and is equally strengthened for his motion with the two poles of the earth: but under the poles, he standeth crosswise, at right angles with the Axis, his centre representing the very pole of the earth itself; so that the equinoctial, and the Horizon being there all one, if the needle should have any horizontal motion there, it must needs be an East or West motion parallel unto the equinoctial, directly contrary unto nature, and to all Magnetical doctrine.  
Yet at the pole, the inclinatory needle is in his chiefest strength, framing himself to be in the same direct line with the Axis of the earth itself: so that the vicinity of the nearest pole of the earth, holdeth his convenient end of the needle most strongly, being nothing at all hindered by the adverse pole, to affect the upper (or other) end of the needle. The which in all other situations either more or less it doth, and especially under the equinoctial, where each pole affecting his convenient end of the inclinatory needle, it must stand very goglingly and unsteddily for that motion: although most strongly for the horizontal, if you place him accordingly.  
Where hence it followeth, that near the equinoctial large compasses, and small inclinatories are fittest; and near the poles large inclinatories, and small compasses are best, for look unto what motion the Magnetical force is weakest, the smaller instruments ought for to be applied.  
And moreover, for as much as the Magnetical revolution of the inclinatory needle, about the globe of the earth maketh his motion for the difference of every alteration of Latitude near unto the equinoctial, far more large & easier to be discerned, than it can be near the poles, therefore a less Instrument will serve the turn there: And because that near the pole, his motion for differences of Latitudes are exceeding small, and hard to be discerned. Therefore very large instruments inclinatory are there to be used, especially because the Magnetical strength of the needle for that motion, is there so strong and steady, that it maketh some recompense for the slowuesse of his moving. And therefore I suppose that three in Diameter, will serve near the equinoctial, and fifteen near the Pole.  
And because this great one may be the less cumbersome, you may cut off the circle at forty and five degrees of each side of the Zenith and Nadir of the Instruments, and yet leave the needle scope enough, for all Latitudes between sixty Degrees and the Pole: and for the the steady standing of the inclinatory instrument at the sea, you may do thus: about the middle of the instrument (or rather somewhat above the middle) let there be two round pins of brass, about three quarters of an inch long, issue out; and in a box of a sailing Compass, the inner circle being taken away, make of each side two half round notches in the outer circle, there place the Instrument upon those two pins, the which must have towards their ends, littles circles cut in, that they slip not out of their rings that they are placed in: then will this Instrument stand as steady, even at sea, as the sailing compass will do: for the motion of the inner circle is performed by the turning of those two pins in their notches, and the outer circle is common unto them both, always remembering that you hang some pretty weight in the bottom of the instrument, to make his motion more certain: If the shadowing of the box hinder your sight from discerning the point, that the needle standeth at, it is soon holpen with the light of a little wax candle put down unto it: and yet this you ought to understand as aforesaid, that the Horizontal and inclinatory motions are but one and the self same effect of the touch of the Loadstone, and one and the self same needle will very well perform both motions, namely, the inclinatory needle, not the horizontal, because his placing upon the pin maketh him very unfit for the inclining motion. But the inclinatory needle resting with one point of his Axis (the points of his Axis being very sharp) in his little hole, his box being placed parallel unto the Horizon, will perform the horizontal motion very well. For being placed with the sharp point of his axis in that hole, it is all one in effect, as the Horizontal is with his capitel on the sharp point of his pin, but that the one is upward and the other downward, & yet either of them being as fit for that motion, as the other. Upon the consideration hereof, my workman of Winchester minding to present Prince Henry with a rare Instrument, contrived an equinoctial Dial & an Inclinatory Instrument both in one, and one needle to serve very well both those turns. Herein now appeareth the wonderful wisdom of our God, in limiting his times and seasons for the revealing of these wonderful properties for the use of men, in this poor stone; namely that above 2000 years after that it was known and wondered at in the world, for lifting up of iron (for it was an antiquity in Plato's time) the use of the horizontal needle was known, in common use, scant 200. years agone; and very few years since (yea scant as yet) the inclinatory is in any common use: and who is there that can behold and consider both these uses, viz. both to show the quarters of the world (as East, West, North and South, etc.) and also the Latitude of the place: to know both these in any place of the world, be the heavens never so much overcast with clouds, who is he, I say, that can behold these two admirable and precious uses performed, even with the turning of an hand, the which neither the Grecian Philosophers, nor the fine-witted Romans, nor the Persian Magis, nor the Indian Gymnosophists could find out with all their skill and cunning, but he must needs say with that Kingly Prophet, O Lord, our Lord, how great is thy name through all the Earth, who hast set thy glory above the Heavens?    

To the Worshipful my good friend, Mr. William Barlow at Easton by Winchester.  
REcommendations with many thanks for all your pains and courtesies, for your diligence and inquiring, and finding divers good secrets, I pray proceed with double capping your Loadstone you speak of, I shall be glad to see you, as you write, as any man. I will have any leisure, if it were a month, to confer with you, you have showed me more, and brought more light than any man hath done. Sir, I will commend you to my L. of Effingham, there is here a wise learned man, a Secretary of Venice, he came sent by that State, and was honourably received by her Majesty, he brought me a latin letter from a Gentleman of Venice that is very well learned, whose name is johannes Franciscus Sagredus, he is a great Magnetical man, and writeth that he hath conferred with divers learned men of Venice, and with the Readers of Padua, and reporteth wonderful liking of my book, you shall have a copy of he letter: Sir, I purpose to adjoin an appeudix of tx or eight sheets of paper tu my book, after a while I am in hand with it of some new inventions, and I would have some of your experiments, in your name and invention put into it, if you please, that you may be known for an augmenter of that act. So for this time in haste I take my leave the xiiijth of February,  
Your very loving friend, W. Cilbert.   

Faults escaped.  
IN the Preface speaking of Claudianus: serediticall for sideriticall. fol. 12. lin. 22. reciprocated for riciprocally. fol. 50. lin. 21. hangings for hugeness. fol. 53. lin. 16. as may be, for as many be. fol. 57 lin. 10. but this is not: for this is not. fol. 68 lin. 19 supposeth the fly, for supporteth the fly. fol: 79. lin. 11. set the same: for set the Sun. item lin. 27. the difference is then: for, the difference is ten. fol. 82. lin. 8. higher: for, heavier. fol. 84. lin. 26. three in Diameter: for, three inches in Diameter. fol. 85. lin. 10. littles circles: for, little circles. The last line save one of D. hearts letter, act: for, art.   

A BRIEF DISCOVERY OF THE IDLE ANIMADVERSIONS OF MARK RIDLEY Doctor in PHYSIC upon a Treatise entitled, Magnetical Advertisements.  
— moveat Cornicula risum  
Furtivis nudata coloribus—  
LONDON, Printed by Edward Griffin for Timothy Barlow, at the sign of Time in Paul's Churchyard. 1618.   

TO THE RIGHT NOBLE AND WORthy minded industrious Gentlemen, and others who are any way addicted unto MAGNETICAL Knowledge.  
SO it is that for a long time I have been greatly delighted in the contemplation of the properties and virtues of this admirable creature of God which we call the Magnet, or Loadstone. And as my leisure and occasions have served by conference from time to time, with the skilfullest Navigators of our age, by reading all the Treatises (as came unto my knowledge) of such as had written thereof, and therewithal trying by practise the truth of those things which I doubted of, and lastly finding some things by my own experience of good importance by others not at all mentioned. The chief of these which I judged profitable for common use I did set forth in a small Treatise entitled Magnetical Advertisements. And although of mine own loving affection towards such (as ye are) I have been always ready to further you in these knowledges the best I could, yet I do assure you faithfully, that divers of good judgement, learning, and eminent place, (unto whom I communicated my experiments) very vehemently urged my publishing of them.  
A copy of this Treatise being by stealth written out of my Manuscript, by one that understood it not, and by that means committed divers errors, this Doctor Ridley devoured some of them, and by his endeavouring to square my propositions according to his own conceits, and so superciliously to control (and censure the things which he understood not) he hath miss of the truth very far and wide, and hath herein wronged both himself, and me, and his readers, but most of all his believers; and yet such is his kind disposition, that he hath purloined out of the scambled copy of my Treatise, for to adorn his own Treatise of Magnetical bodies and Motions all these that follow; as in his Treatise, 

Fol. 7. The hilly knobs, and angulous parts etc. for 17 lines.  
Fol. 8. The greater stones &c. 5 lines.  
Fol. 9 Steel and iron etc. 4 lines.  
Fol. 10. The 14. 17. 18. 19 figures are mine.  
Fol. 18. 19 The 1. 2. 3. 7. ways are mine, the 4. Doctor hearts.  
Fol. 22. Every part and piece of a Loadstone, etc. 7 lines.  
Fol. 27. If a wire be touched etc. 5 lines.  
Fol. 30. & 31. It is to be observed in the fashion of a Magnet etc. 16 lines.  
Fol. 36. For although that naturally &c. 9 lines.  
Fol. 51. & 52. Also if a Magnet be fastened etc. 4 lines.  
This practice is profitable for travelers etc. 14 lines more.  
Fol. 63. 64. The best way to touch etc. 11 lines.  
And some have thought it better etc. 14 lines.  
Fol. 66. Set two Lodestones etc. 3 lines.  
Fol. 71. An Adamant doth loose much of his virtue etc. 3 lines.  
Fol. 72. That 20. Chapter (only a few words chopped and changed) is whole mine.  
Fol. 83. And for this cause the Adamant etc. 3 lines.  
Fol. 89. A piece of Steel well tempered etc. 2 lines.  
The two next are his own, and very absurd.  
Fol. 90. Now it is to be observed etc. 10 lines.  
Fol. 95. The needles and compasses etc. 14. lines.   So that it cannot but seem to any indifferent person very strange, that Doctor Ridley would publicly so traduce me, and that by name, and so contemptuously in his frivolous Animadversions, and could never hit upon my name, no not so much as once to acknowledge it in all these things which he hath by stealth learned of me, and inserted into his Magnetical Motions for his own, the which with their consequents if you withdraw from his Treatise, you will leave his motions very dull. For except this Ridley, had ploughed with my Heifor, he had not known my Riddle. Sic vos non vobis.  
In my advertisements indeed, I made mention that some body had in this manner dealt evilly with me, and I reproved certain faults that some body had committed, especially in the fundamental Magnetical hearesayes of misnaming of the true North and South, in Magnets and Magnetical bodies, and in making the Inclinatory needle with the one end heavier than the other, and some others: But these two especially, for because they do draw on many others, as they do both in his Book, and wheresoever they shall be admitted, they will increase like a snowball, waxing still greater as they go, and all his daubing of them with his untempered mortar in his silly Animadversions do amend the matter nothing at all, but make it far worse than before. For the common good, I might not let them pass unreproved, and yet I would not publicly name him, but used this word somebody. The like himself hath, viz. Some say, some labour to clear, some think &c. in his book meaning me, being not contented only to usurp that which was properly mine for his own (as aforesaid) but also he took upon him (although very ignorantly) to confute some of mine under these terms, and this only out of a stolen Manuscript. Whereas all men know that Manu-scripts ought to be uncontrolled until the Author hath published them, who may alter and change things in the mean space as he thinketh good.  
He styleth himself principal Physician unto the Emperor of Russia, the which many men wonder at, being so young as he than was, and supposed that he went over only as Physician unto our Merchants there, that he should in so short a time become that Emperor's principal Physician. If he were, he sped better than Bomelius did, who is said to have died there in that cold climate of the extremest hot kind of Calenture.  
Out of all question, somewhat it is more than ordinary, that maketh him of so haughty a spirit, so to brave the world with such prodigious assertions of his Magneticals, in, and above the Moon; the earth's Magnetical circular Motions, and his paltry abusing of the holy scriptures to support his lunatic fictions under the name of Magnetical Philosophy.  
There are yet two texts of Scripture, which it is a wonder how they escaped him; the one is in josuah 10. ver. 12. and the other is in Esay 38. ver. 8. In the one: That the Sun and the Moon stood still the space of a whole day: The other, that the shadow in Achas dial went back 10 degrees, and the Sun in the sky returned 10 degrees by the which he was descended.  
For it is his guise to make contrary conclusions unto that which the Scriptures affirm, and therefore blame him not, if he do so despise Aristotle, who never taught any such Logic.  
Now therefore that ye may in few words understand the untruth of the earth's Magnetical Motion, that is so mainly emblazoned by him, and the weakness of my Animaduersors Magnetical skill, you must know, that the Magnetical Motion is a natural inclination of two Magnets or Magnetical bodies, that may freely move, respecting the one the other within the Orb of their forces with their convenient ends, that is to say, the North end of the one always respecting the South of the other.  
If the two Magnets or Magnetical bodies be of like quantity, form, and goodness, their Motions will be of like quickness of the one towards the other; but if they differ in any of these, their Motions will be so much the slower.  
Now forasmuch as all Magnetical motions are always respective of the one Magnet or Magnetical body towards another, it followeth by necessary consequent, that no Magnet or Magnetical body, can either move, or be moved of itself, but is utterly void of all intrinsical or selfe-Motion, the true and only cause of his Motion being evermore without itself.  
And therefore mine Animaduersors selfe-motion of the Globe of the earth circularly, by Magnetical vigour, in the which he doth so gallantly triumph; is but an idle figment, and a mere Chimaera: but his definition of Magnetical bodies is very suitable unto it; viz. very monstrous; namely, That we define to be a Magnetical body, which doth remain and place itself in one place, or kind of situation natural, not alterable, as all stars do, and the great Regent globes of Saturn, Mars, jupiter, the Sun and the Earth do: or such, as with respect and attendance follow other globes, as the two stars which support Saturn; the four attendants upon jupiter, lately discovered by the truncke-spectacle; the two traversers about the Sun, called Venus and Mercury; and the Moon, which doth follow or go about the earth, and respecteth the same always with one Pole, and therefore hath a peculiar Magnetical virtue, that guideth her in this kind of situation.  Auditum admissi, risum teneatis amici, 
Any man that considereth this goodly definition, being the foundation and ground of his Magnetical discourse, and the very first sentence of his book, and many the like fancies in his Motions and and Animaduesions will easily discern what his Magnetical skill is, and what a vanity it were for me, to spend any precious time to confute in particular such unreasonable and senseless opinions, which have more need of Helleborus to purge them out of his head, than Arguments to confute them in his book. And in his frivolous animadversions seeking to maintain his former errors, and he being so snappish to have them amended, he maketh them ten times worse than they were before, and far more palpable: But my tetrical Animaduersor must be ruled by reason, and afford all those his patience that do believe the holy Scriptures, which flatly do deny the Earth's motion, and affirm the motion of the Sun, Moon & Stars, in the whole current thereof, as Psal. 19 6. 104. 5. josua 10. 12. 13. 14. Esay 38. 8. etc.  
Also that he will give men leave to credit their senses, in matters subject unto sense, and not repugnant unto reason; and that he will not be offended with those who do pitifully laugh at his Magnetical Astronomy, with those topsy-turvy motions, like  Voluitur lxion, & se sequiturque fugitque. 
For although some great learned men in those Sciences, have used the supposed motion of the earth, for an Hypothesis, serving their ready calculations; as they have done also their supposed Epicycles, for the motions of the Planets and their courses: yet that is no reason for to avouch them for to be in themselves true and real things, according unto some men's vain fancies, who do argue after this sort.  
It is an easier matter, and more (as they say) agreeable unto nature, for so small a body as the globe of the Earth is in comparison of the heavens, to move circularly in the space of four and twenty hours, than it is for the huge Universe so to do; and that which is done with less hazard, is to be preferred before the like, which may not be performed without fear of a greater danger, with divers other reasons like unto these.  
But although such as these are, may go current in a mechanical Tradesman shop, yet they are very insufficient to be allowed for good, by men of learning, and Christians by profession, who know right well, that it is great folly for to oppose that which we call difficult, unto an omnipotent power, Who stretcheth out the heavens like a curtain, and spreadeth them out as a tent to dwell in, Esay 40. ve. 22. He stretcheth out the North over the empty, and hangeth the earth upon nothing, etc. job 26. ver. 7.  
And that which we call Nature, it being nothing else but God's ordinance; there can be nothing contrary, but all things agreeable unto nature, which God hath ordained. But God hath ordained the motion of the Sun, Moon, and Stars (as aforesaid) and the unmooveablenesse of the earth; therefore this is more easy, and more agreeable unto nature; which is preserved only by obeying God's ordinance, and herein only that consisteth, and hath her being. And that the earth's magnetical virtue hath no power at all to perform or help any such motion, as is also before made manifest.  
But that mine Animaduersors magnetical skill is ascended up into our Moon itself; yea, and yet higher, far beyond the Moon, unto the other Planets and Stars, and into every one of them, this is such a point of his Magnetical Philosophy, that would make Stupidity itself astonished to hear of it.  
There was (as the Poets feign) a certain King of Phrygia, that had a gift given him of the Gods, at his own request, that whatsoever he touched with his body should be gold, but by that means being ready to starve, because his victuals were also turned to gold, he entreated earnestly that he might surrender his gift.  
It seemeth that mine Animaduersor endeavoureth for to make show, that he hath a stranger gift; namely, that by his very looks (for his looks, with his Truncke-spectacle, are his means) he can turn all things to be Magnetical, that he doth earnestly behold; He hath scoured the Heavens already, even from the one end unto the other, that both Planets and Stars are become magnetical in his head; what tumultuous stir may they breed there, no man can tell, it is his safest way to confine his Magnetismes unto the earth, as their natural seat, and not suffer them to clamber up into the skies, where they have nothing to do, lest that infinite dispersion of his magnetical knowledge, do in the end overcharge his brain, and make him magnetically mad, or at the least to incur the censure of him that said,  Delphinum siluis appingit, fluctibus aprum. 
As therefore whilst his wits are yet his own, it is his surest way (like the King of Phrygia) to surrender that gift again, to leave his trifling with the holy Scriptures, and to be no more a censuring Animaduersor in matters that he hath but small skill in: and that he will hereafter learn to be wise unto sobriety, Metirise quemque suo modulo ac pede verum est. And forasmuch as his animadversions contain nothing at all, of any truth and importance against mine Advertisements, but only many ignorant, many wilful mistake, contradictions & cavillings, and maintaining of his former absurdities, the which the more they are stirred by him, the more they stink. I will content myself with this brief discovery of this Animaduersor, and his animadversions, and so to leave him for this time peeping in his truncke-spectacle at his celestial magnetical regent globes, with his proud motto: Non sufficit orbis. To try whether he can yet find us here hence any more new glorious dreams, whereby he may either increase the number of the hundred of merry tales, or else augment the noble history of Huyn of Burgis.  
And whereas he chargeth me opprobriously for to have in my Treatise nothing of mine own, but all of other men's, and some of his: mine answer is, that he knoweth in his own conscience (if he have any) that he speaketh a manifest untruth, contrary unto his own knowledge in both. Yea, I am verily persuaded, that if he would but give his own conscience, leave to speak out, it would ring him a tale in his ear unto this effect: That he himself knoweth right well, that where my knowledge (even such as it is) in these matters faileth: all the store of skill that he hath, cannot advance it, no not so much as one straws breadth, notwithstanding all the great countenance he setteth on it, with his swelling titles of his Magnetical bodies and motions, and his aristarchical censuring of my Advertisements. Nil dignum tanto feret hic promissor hiatu. And for my just defence, I will rehearse but these few things (yet such as are of principal importance in this Art) whereas I could name divers other.  
I was the first that made the inclinatory instrument transparent, and to be used pendant, with a glass on both sides, and a ring on the top, whereas Doctor hearts hath but of one side, and to be set on a foot. And moreover, I hanged him in a compass box, where with two ounces weight he will be fit for use at sea.  
Another is, that I was the first that found out and showed the difference between iron and steel, and their tempers for magnetical uses, which hath given life and quickening, universally to all magnetical instruments whatsoever.  
I was also the first that showed the right way of touching magnetical needles.  
I was the first that found out and showed the piecing and cementing of Lodestones.  
I was the first that found out and showed the reasons why a Loadstone being double capped, must take up so great weight.  
These things (ye worthy Gentlemen) have I mentioned only to give you content and satisfaction: For although my magnetical knowledge be no manner of way gainful unto me, as all that are acquainted with me, know how little I do esteem of it in any such respect, yet forasmuch as I have published my Magnetical Advertisements of my very earnest affection towards such as ye are, and dedicated them unto one right worthy Gentleman of your Society in steed of all, even for your sakes I could not suffer my pains and good will towards you, to be so scornfully trampled under foot (without some gainsaying) and prattled out of conceit with cavilling only, and multiplicity of vain words and peevish bravadoes, The Lord prosper you in all laudable knowledge and virtuous practice.  
Yours in all hearty affection▪ W. BARLOW.