Section 48

Chap. XXX. A Loadftone on a plate of iron}will not fiir iron*
\AfE f*id that there is nothing coming between , can hinder the force of iroj?, but iron onely : fo that if you lay a needle on a plate of iron, and flhall bring your Loadftone to it, above or beneath, it hath no vertue to attract it, cr do its office : and the reafon is eafie. For it ftands by realbn, that if iron lye upon iron , they are the fame body, as a partis of the whole: and when the plate of iron, or piece, is big?ers and too heavy for the Loadftone to draw, it moves nor. So that if you pu:. the filings of iron upon a plate of iron , and with your hand underneath , you carry the Load- ftone , the filings will not ftir, but ftand ftill upon the plate. Nor if iron or a Load- ftone be upon a Table of iron , will they come to the ftone that is put to them , but will lye as if they were afleep, and void of all vertue , or changed in their Natures. Alio, if you put flat iron to a Load ftone , if on the other fide iron be equally balan- ced , it will not ftir, nor move to meet it •, as if all the force of the Loadftone were hundred by it. Lucretitu faith, that it will happen fo, not when iron, but brafsis between them : but I rather think he writ fo by hear-fay , then by his fight , if we uoderftand his meaning.
. Pieces of iron 1 have feen9
When onely brafs was put between Them and the Loadftone , to recoil: Brafs in the middle made this broil.
Chap. XXXI. Thepofttion of the Iron, will change the forces.
"yyHat the Loadftone can do , the iron touched by the Loadftone, will do the fame. I faid, that the Loadftone equally balanced , by putting the fouth pare of the Loadftone above, it will draw the north part, and thenorth part will drive off the north part ; but on the lower part, the Nature being charged, that which drew before, drives off now • and that which drove off, draws to it. The fame I judge of iron touched with the Loadftone. For iron in the Mariners Ccmpafs touch- ed with the Loadftone , that part of the Loadftone that draws and drives eff in the upper part, being put under, expels what it drew before, and draws what it expelled. I would not omit,that amongft its admirable properties,the pofition fhould caufe fuch alteration. Whence we may corje&ure,that as the ftone hath a pole-ar£tick and an- tar&ick ;foit hath an eaft and wc(i part, and its upper and nether part, as the heavens have : and therefore it is reafonable, that whereas the north and inferiour part from above , drew the fouth and inferiour part of the iron ; now the pofiticn being chan- ged, the upper part of the ftone will draw the nether part of the iron.
Chap,
%o6 Natural Magick. ^Boof^j. *
Chap. XXXII.
That the iron rubbed with the northern point of the LoadfioKe^rvilltHrn to the fouth tand with
the [oath point to the north,
I Come to the third part, that is, to the iron touched with the Loadftone, and they are all wonderful. Hay then, that when we know the north point of the Hone, and we have rubbed one end of the iron wich it, if it be equally balanced , or hung by a thread, or lie freely in a boat,it Will turn of it felf to the fouth. And that hands with real'on : for the Load 'One imparts its force to the iron. Fork is the natural force of the Load tone , that being balanced equally, it fhould turn its north point to the north, and his fouth point to the fouth. But when it is rubbed on the iron, the upper part of the Loadftone is faftned to the iron ; but the lower part that is neer to it, is free'd: wherefore, if you rub the iron with the north part , which fartneth to the iron, andtoucheth its external fuperficies, it will be northern that feemsto to be fouthcrn , and this fouth part will turn freely to the north. But contrarily, if you ru5 the fouth point againft the iron, the fouth point is faftned to the iron , and the north point is let loofe that turns to the north. Wherefore C^anm (peaks falfe , that the iron touched by the north point , will turn to the north , and that which was touched by the fouth point , will turn fouth ; for we fee the contrary. Yet the iron mult be touched with one point , either the north or fouth point : for if ore part bend northward, the other wiiltend fouthward; by the ufe whereof, fo large feas are fail'dover, that being the conductor. Our Anceftors failed, by feeing the fun by day , and the ftars by night. For in the middle of the fea, as they wandred , they could no otherwife fee the coafts of the world. But wecannot one- ly difcover what coaft we are in, but we can avoid the rocks under the waters ; and in cloudy days and dark nights , we can at all times know the poles of the world. Fl.tvim faith , an Italian found it out firft , whofe name was Amalphm , born in our. Campania. But he knew not the Mariners Card , but ftuck the needle in a reed, or a piece of wood , crofs over ; and he put the needles into a veflel full of wa- ter, that they might flote freely: then carrying about the LoadN one, the needles would follow it ; which being taken away, as by a certain natural motion, the points of the needles would turn to the north pole • and having found that, ftand ftill.' Wherefore, knowing the place before they fteer'd their courfe thither. Now the Mariners Compafs is made, and a needle tou.hcd with the Loadftone, isfo fitted to it , that by difcoveringthe pole by it , all other parts of the heavens are known. There is made a rundle , with a Latir.-navel upon a point of the fame metal , that ic may run roundly freely. Whereupon, by the touching onely of one end , the nee- dle not alone partakes of the venues of it , but of the other end alfo , whether ic will or not : For if you rub the needle with the north point of theftone prefently that part will turn to the fouth , and the oppofite part to the north ; and one vertue cannot be imparted without the other. So the needle touched by the fouth point of the flone , will turn to the north , and the other part to the fouth ; fo that the part of the needle that is touch'd, receives a contrary force, from that the flone hath.
Chap. XXXIII.
That iron ton :hed by the LoadftoKe^will impart that force to other iron,
1 Ron touched by the Loadftone, by that touch receiveth the vertue of the Load- 1 (tone, that it will do almoft as much by attracting, and effe&ing, andturningit felf to the pole. So the iron hanging freely , touched with the fouth point of the Loadftone, will turn freely to the north : if you applv the fouth part of the ftoncto the fame, it will turn to the fouth prefently. But if you touch another iron with the iron that was touched, that will turn to the fouth j and do but point at ic with the
Of the Wonders of the Loadftone. 207
faid point of the iron , it will turn to the north. And this force is not onely fenc • into the fecond iron , but to a third and fourth, is the force of the Loadftone is. For if it be a ftrong ftone, it will fend its vertue through eight or ten needles.
Chap. XXXIV. The virtue received in the irony is weakned'hy one that is ftronger.
YEt this I muft tell you, that the vertue received by the iron , is not fixt and cer- tain , but is taken off by a ftronger that takes it from it. As an iron touched by a weak northern point of the Loadftone ; if you rub the fame part of the iron with a fouth point of a ftronger Loadftone , it will vanifh, and that former force of turn- ing it felf to the fouth, is taken away, andic takes a fom hern vertue , and will turn to the north without refinance. But if the Loadftones be of equal force, they are fo aftonifhed and blunted, that they will neither receive both, nor either.
Chap. XXXV. How in a fione the fouth or north point is difcerned.
AMongft thofe ways I fhewed before , I fhall fet down this alfo . and perchance thisisthebeft, how to know the true northern and fouthern points. Let the Loadftone be turned round, by the wheel of the Jewellers , and poltfhed. Then make a flender iron, as long as theaxelcreof that round ball, and lay that upon iheftone: for it will turn it felf upon that line, that points juft north and fouth. Mark the line upon the flone, with fome delible paint: do the fame on the other- fide of the ftonej and where it refts upon the ball, draw the fame line: do the fame the third and fourth time , upon the middle of it : and where thofe lines crofs ©ne the other and meet , thofe are the polar points. We may alfo find it out thus : Break a fmall needle, and put the fmalleft piece upon the fame ball, andftirit; for when it comes to the juft northern point , the needle will ftand upright, that will make ftanders by admire, and will ftand perpendicularly upon it : and till it do rife thus, be not weary of moving it up and down ; for when you have found ir, you will be glad of ir.
Chap. XXXVI. Horv to rnb the iron needle of the Mariners Compaft.
I Know that fome are troubled how to rub the needle in the Compais with the Loadftone, that it may get force to turn it felf to the north Pole. It muft be done thus : When you have found the points in the ftone , as I faid before ; ftrike the points lightly with a hammer, and the plates will be full of ttiff hairs : upon which if you rub an iron needle , it will prefently get vertue to turn it felf to the Poles. Yetobferve this , that if you would have your needle turn to the north , you muft rub it on the fouth point ■, but if to the fouth, rub itwith the north part : For when it is equally balanced , it will turn to thefc points in the heavens. But that it may do it more forcibly , and do its office more exa&ly , I fhall lay down fome rules fit to inftruft you. If you ftrike both ends of the ftone with the hammer , that hairs may appear on both parts ,thtt you touch the needle at both ends, for fo the needle will fooner do its office. Moreover, you muft obferve very carefully , that when the iron rub'd againft theLoadflone, hath received thefe hairs , that you touch it with no other iron or Loadftone , but keep it far diftant from them , and lock it up in a box ; for by touching of others the iron will grow dull , and lofe its vertue , thac ic will never point out the parts of heaven perfectly. For the iron coming within the Cooapafs of the vertue of another Loadftone, will receive that , as we faid. So the needle rriuft be proportionable to the ftone. For from a little Loadftone,a great
iron
208 Natural Magic k.
iron will not receive much venue, nor (hew the pole : alio, a little piece of iron can- not receive much venue ; for it confumes by the great force of the Loadftone. More- over, the point that (hews the pole , muft not be fharp, but fiat a little , that it may receive thofe venues of the Loadftone exactly , and hold them; for in a very fbarp point, fcarce any venue will abide. Iron, the purer it is, the better will it hold the vertue. For it will hardly take upon foul and rufty iron : wherefore Mariners make it of pure fteel; for fteel is made of the beft iron. If you obferve this, iron once rubbed, will hold the venue a hundred years ; and will certainly, without failing, point exactly at the poles in the heavens, for fo long time.
Chap. XXXVII. Of the divers ufes of Mariners Comp*Jfest
ANd the needle touched , doth not onely (hew the poles for the Mariners ufe, but almoft it fcrves for infinite nfes ; as all men know that ii is day ly fpokea of every where. I (hall fpeak of fome of the chief. The ufe of the Loadftone upon the needle, is well known in Sun-dials : for when the needle ftands ftill over the line that is made from north to fouth , we are fo directed by it , to know the hours by the fhadow falling from the Gnomon. Alfo, thofe that work in Mines ufe the needle, to find the veins of the metals , which way they run : for in caves under ground, in that poflure the needle ftands that is touched whh the Loadftone, they know the veins of the metals run on that tide of the heavens. Alfo, it doth ferve ve- ry much for thofe that describe platforms of buildings, cities, countries, whilft the fi- tuationof the corners are taken anddefcribed upon the paper. We ufe it alfo in making paflages,for to bring water under ground , in digging pits , in making Mines and Trenches , wherewith they ufe, with great skill , to blow up Forts , Caftlcs, Rocks and Walls, by putting Gunpowder into them, and flopping all places of vent : the Compafs guides them how to go on. Laftly ,how to level the discharging of Canon, both by night and day, it is of lingular vertue, and for many other ufes, too tedious to relate here.
Chap. XXXVIII. Hon* the Longitude of the war Id ', m*J h found out If J he If of the Loadfltne*
I Will not omit, that amongft the principal ufes of the Loadftone, by the help of it the Longitude of the world may be found our. Which notable work hath cm- ployed the wits of the moft knowing men. It hath been obferved a long time by our men, that the needle touched with the Loadftone , will not always reft upon the Meridian line , but fometimes will decline nine degrees from it te the eaft ; nor will it hold the fame pofture in all places ; but in divers places, it hath divers decli- nations. But this errour feems to follow this order,that the neerer it is to the eaft, the more it will decline from the Meridian line, toward the eaft; and the neerer it comes to the weft, the point of the needle will decline the more to the weft. For finding the Meridian line , as Ftolomy and other Geometricians teach how, and fetting up a point thereon,that the fteel needle may turn freely upon the top of ir, in Italy it declines toward the eaft nine degrees, of which there is ninety in a quadrant of a circle, a defcribed. Moreover, many famous travellers report, that amongft the Fortunate Iflands, one is called the Azores , where the needle fet in the Compafs , will reft dire&ly upon the Meridian line , without any variation at all. Alfo, they that fail to the weft-Indies obferve, that the point of the needle will decline to the weft. Therefore, laying down thefe for true Maxims , we may eafily know the longitude of the world : for if we make a very great Compafs , about five foot diame- ter , and divide the degrees and minutes , into feconds and thirds, &c.
Of the JVonders of the Loadftone. 2 dp
and failing under the Equator, we do obfervc the chief motions of the Needle, and the declinations of ic,and (hall accommodate the i'anae to the proportion of our Voy- ages; we ^all eafily know the Longitude of the Woild,beginning from the Fortunate lflands. Whence both Longitude and Latitude in dark nights,and the greateli Tcm- pelt* may be certainly difcovered Wherefore it is falfe that C W Needle in theCompil's declines from the Meridian Line , becaule it inclines to the Pole Star in the little Bears Tail : whereas* the Needle declines nine Degree?, and the Polar Inclination is not fo much.
Chap. XXXIX.
If the CMariners Needle ft.ind (till, And the Loadftone tnovey or contrail fyy the) will
move contrary vttys.
IT the Loadftone lie on the Table, and you put the North point of the Mari- ners Needle to the South point of the Hone , and fhall carry it round about by the right hand , the Needle will draw to the left : but moving th&Box to the lefc hand , the Needle will run to the right ; and it will go fo far , until it Mand in the middle between thole two oppofite pcints. The tame will be ieen in a Sun-Dia], if that Mand , and the Loadftone be carried about : for if you decline to the righc hand, the Needle will follow the fame part ; and likewife, if you turn to the left. Hence it is apparent , That the Needle in the Compafs is drawn by the North- Pole : for thofe that fail toward the Eaft , have it turned toward the Eaft ; and fo comra- rily to the Welt, ic will move to the fame point of the Heaven : and if the Load- Hone be turned about , the Iron will turn about alfo, as a pair of Compaflcs about the Centre.