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    Re: Regiment of the Sea
    From: Peter Fogg
    Date: 2009 Oct 15, 20:45 +1100

     KENT AE NORDSTRÖM asks:
    Brad, is it possible to distribute this file with an older version of MS Word?

    Here is a simpler solution:

    William Bourne

     A Regiment for the Sea

     1574

     

     

    The sixt Chapter or rule she-

    weth, how to take the heigth of the Sun

    with the crosse staffe or with the Astro-

    lobe, and also how to find the true

    Meridian, with other neces-

    sarie matters.

     

    To take the true heigth of the Sunne at the Sea, beste way is,

    to doe it with the crosse staffe: for that the Sea is moueable, and

    causeth the Shippe to heaue, and sette little or much: and also

    vpon the scrosse staffe the degrees be larger marked than the

    Ring or Astrolobe: and in a large instrument an errour is seene

    sooner and better than it is in a small instrument.

    Nowe to take the heigth of the Sunne, to knowe they Alti-

    tude of the Pole aboue the Horizon, doe this: Firste set the

    Sunne with a compasse, to knowe when that the Sunne com-

    meth near vnto the Meridian: as soone as you see that the

    Sunne is come vnto the South and by East, then beginne to take

    the heigth of the Sunne with the crosse staffe in this manner:

    Put the Transitorie vpon the long staffe, then set the end of the

    long staffe close at the corner of your eye, winking with your

    other eye, and remouing the Transitorie forwardes or back-

    wardes, vntill you doe see the lower end of if (being iust with

    the Horizon_ and the vpper ende of it, (being iust with the

    middle of the Sunne) both to agree with the Sunne and the

    Horizon at one time: and so haue you the true heigth of the

    Sunne: this doe, stil ovserue ye same, vntil you see the Sunne

    at the highest and beginning to descende, and they haue you

    finished.  Yest notwithstanding this is to be noted: that it is beste

    to take the heigth of the Sunne with the crosse staffe, when then

    Sunne is vnder 50. degrees in heigthe aboue the Horizon,for

    two causes.  The one is this: till the Sunne be .50. degrees in

    heigthe the degrees be largely marked vppon the crosse staffe,

    but after (the Sune being aboue .50. degrees high) they be

    lesser marked.  The other is, for that the Sunne being vnder 50.

    degrees in heigth, you may easily take the height, bycause you

    may easily see or viewe the vpper end and nether end of the

    crossstaffe bothe at one time: but if it dothe exceede .50. degrees,

    then by the meanes of casting your eye vpwardes and down-

    wardes so much, you may soone commit error, and then in

    like manner the degrees be so small marked, that if the Sunne

    dothe passe .50. or .60 degrees in heigth, you must leaue the

    crosse staffe and vse the Mariners Ring, called by them the

    Astralaby, which they ought to call the Astrolobe.  Nowe to

    take the heigth of the Sunne with the common Ring or Astro-

    love, doe thus: The Sunne being (as before is declared) neare

    the Meridian or South, ovserue it (vntill you haue the greatest

    heygth thereof) in this manner: Holde the Ring of the Astro-

    lobe vpon one of youre fingers, and turne the Alhidada vppe

    and downe, vntil you see the shadowe of the Sunne pearse or

    passe thorough bothe the sightes thereof, being sure that the

    Astrolobe dothe hang vpright, whiche you may proue in this

    manner: Looke at mowe many degrees and minutes the Alhi-

    dada dothe stande vppon the Astrolobe, then turne the Alhidada

    vnto the same number of degrees and minutes on the other

    sode of the Astrolobe, then taking the heigth of the Sunne

    againe, if it doe agree as it did before, then the Astrolobe dothe

    hang vpright. but if it doe not, then it dothe not hang vpright.

    For knowledge of the true heigth of the Sun (the Astrolobe not

    hanging vpright) do thus: if the Astrolobe be truely marked,

    marke the diuersitie, that being knowne, rebate from the

    greatest heigth halfe the diuersitie, or else adde vnto the lesser

    heigth halfe the diuersitie, and that shall be the true heigth of

    the Sunne, although that the Astrolobe doth not hang vpright.

    The Astrolobe is best to take the height of the Sun, if the

    Sunne be very high at .60.70. or 80. degrees, and the cause is

    this: the Sunne coming so neere vnto your Zenith, hathe great

    power of light, for to pearce the .2. sights of the Alhidada of the

    Astrolobe, and then it is not good to vse the crosse staffe, for

    that the Sunne hurteth the eyes of a man, and besides that it is to

    high to occupy the crosse staffe, (as before is declared) so that

    this way you may very much preserue your eyes.  If you haue

    not glasses vpon your staffe (to saue your eyes in taking the

    heigth of the Sunne) but be vnprouided of them, to thus: take

    and couer the Sunne with the end of the transitorie of the crosse

    staffe, unto the very vpper edge or brinke of the Sunne (so shall

    you not neede to heholde the brightnesse of it) and with the

    other end of the transitorie to take the horizon truely, and that

    being done, for that the Sunne is .30. or .31. minuts in diameter

    or bredth, therefore you shall rebate .15. minutes from the

    altitude or beigthe of the Sunne, and then that whiche shall

    remaine shall be the true heigth of the Sunne from the center or

    middle of the Sunne.  And furthermore there is some error in

    the taking Sunne or Starre with the Ballastel or crosse staffe,

    and that groweth by this meanes: for that the true center

    (which is the sight of the eye) is within the middle of the eye,

    and not in the outside of the eye, so that the end of the long

    staffe in the setting of it vnto the corner of your eye, dothe

    stande somewhat further out than the sight of your eye, that is

    to saye, that the sighte of the eye is somewhat further into the

    head, than the ende of the staffe dothe come: wherefore you

    must pare away a little of the ended of the staffe, for some mens

    vses more, and some mens vses lesse, for that it is according as

    you may set the staffe vnto your eye, for some men neede pare

    away little or nothing, and some men must pare away .14. or

    .15. minutes as you may set the staffe: bycause some mens eyes

    be further into their head than other some mens are, and the

    bones of some mens face stand further out than other some do.

    It is moreouer conuenient to know the true meridian, or South,

    whiche you must do, either with a good compasse or with a

    perfyte diall or Needel: but if you be on the land  this you may

    do: on a peece of timber, or any other thing that standeth fast,

    with a paire of compasses make a circle, then in the midle or

    center where the foote of the compasse did stand set a wire

    vprigth (as circumspectly as you can) and then you may do this:

    looke in the morning (so it be on plaine ground that you may

    see the horizon circle, without any let) a the sunne rising, for

    the shadow of the wier, and ther set a pricke: then at the

    setting of the Sunne you shall set another pricke: euen at the

    circumference of the circle, then diuide that with our com-

    passes euen in .2. peeces, and strike a straight line for the wier

    or center of the circle, to the middle or deuided prick, & that

    shal be the true meridian.  Or else (the wier standing vprigth) first

    in the fore noone when the top of the wier doth touch, or is

    ready to come into the circumference or edge of the circle, there

    make a pricke: then in the after noone in like manner, at the

    very comming out or touching of the wyer, of the edge of the

    circle, there make an other pricke euen with the comming out

    of the shadow: this done (as circumspectly as you can) deuide

    these 2. prickes in the midle, then as before is said, drawe a line

    from the center or wier, to the midle prick, and that shadow shal

    be your true meridian.  After another manner you may doe

    this: looke and watch when the wyer giueth the shortest

    shadowe, and there make a pricke: then draw a line from that

    prick to the wyer, which shadow shall be the true meridian.

    And yet furthermore, for yt it is most conuenient to know ye

    true Meridian at the Sea, bicause in long viages going far vnto

    the Westware or Eastward, the compasse doth varie: to find the

    true Meridian do this.  Set the Sunne with your compasse is hir

    rising or appearing aboue ye horizon, & then (knowing what

    point and part the Sune doth rise at) set the Sun with your

    compas at hir setting or departing vnder ye horizon & (that

    being known) you shal perfitly know, whether the compas be

    varied & how much: for ensample this, I doe set the Sun at hir

    rising with the compas & she doth rise vpon the East point: in

    like maner also I do set the Sun with hir compas at hir setting, &

    do find hir to set West Northwest: so I do see the compass to be varied one pointe, thst is to say, the North point doth stand

    North and by East, &c.  And furthermore (for that seldome

    times the Sun dothe rise and set cleere by the meanes of the

    cloudes, and other impediments neere the horizon) you may

    get the true Meridian thus: at any time in the fore noone, first

    set the Sunne with your compas, and then take the true heigth

    of the Sunne.  Now you (knowing how many degress ye Sun

    was high at that point of the compas) may in like maner obserue

    the Sunne in the afternoon, untill you do find the Sun iust at

    that heigth that it was in the forenoone, marking at what point

    of the compas the Sunne is, and so shall you see perfitely

    whether the compas be varied or no, and also howe much: for

    ensample thus:  I take the Sun upon the Southest poynt .20.

    degrees aboue the horizon, & then in the after noone I do ob-

    serue the Sun vntil such time as I do find the Sunne iust .20.

    degrees aboue the horizon again, & then I set ye Sun with the

    compas and do find ye compas to be varied one point, yt is

    to say the North point doth stand North & by East.  &c.

    Another way also to know ye true meridian, is by the Sun: that

    is, to set ye Sun with ye compas at hir greatest heigth aboue the

    horizon, & so you shall know whither ye compas be varied, &

    how much: & looke what is spoken of ye Sun by day, you may

    do the like by night by any of the Starres yt you perfectly do

    know, doing as you do by ye Sun in all points: but you cannot

    do it so well and truly by the Moone, by the meanes of the

    swiftness of ye moones motion in the Zodiack, you may also

    find the variation of ye compas by the North Starre, as thus: set ye

    North Star with the compas, if the North point do stande right

    with the Starre, then it is not varied: and that must be done

    when the .2. Starres of Charles Waine called the pointes be

    right vnder, or right ouer the North Star, but if that the Starres

    be West from the North Starre, then the North Starre is the

    third part of a point vnto the Eastward of the North pole.  If the

    .2. Starres of Charles Wayne called the poynters be due east

    from the North Starre, then the North Starre is the third part

     of a point vnot the westwarde of the North pole .&c. This

    haue I saide bycause that sometine in sundry places, the com-

    passe doth varie, & especially in the sayling of long viages run-

    ning East and West, (called the Northeasting or Northwesting

    of the compasse) therefore I would not wish them to meddle

    with the mending of their compasse or whetting of the side of

    the needell to the end to make it stand due North, but cir-

    cumspectly to awaite the altering of the compasse, and what

    quantitie it doth alter: as you may do very well, by the order

    before rehersed, and then let your compasse alone: for although

    that it dothe varie .2. or .3. poynts, you may make account

    according to the variation as thus: I admit the Northwest point

    standeth due North, and my course is to go due West, I will

    occupy the Southwest pointe in this case for the west poynte.

    And thus ( by oberuation and trying of my compass) I care not

    what point standeth due North, for it is all one, so that you

    consider what poynt standeth North.  And now furthermore,

    come are of that opinion, that (by the Northeasting or North-

    westing of the compasse) you may knowe the Longitude: but I

    am not of the opinion, for I admit that it be so (as some do

    affirme) that the compasse doth varie, (as some haue said) that

    is, that you being .90. degrees vnot the Westwarde (from the

    place youre compasse was made at) youre North poynt should

    stand Northeast: and in like maner you being .90. degrees East,

    your North poynt shoudl stand Northwest: then by that order

    the compasse should vary one poynt at .22. degrees and a halfe,

    and that cometh vnto .450. english leagues (if you be neere

    vnto the equinoctial:) wherfore no master or pilotte of a

    shippe, doth keepe so simple account fo the shippes way, but

    that he may knowe what distance he hath vnto any place better

    than he shal know by the variing of the compas: & also

    whether it be so or not yt the compas doth keepe any such pro-

    portion in the variation, I do refer  that vnto them that haue tried

    the experience thereof: for I for my part can say nothing in that

    matter.  Wherfore I cease from writing muche thereof, al-

    thoughe the Sea men by  very desirous to haue some way to get

    the Longitude.  But if it be true that the compasse doth verie by

    that proportion, then it were very good for them to practise

    that matter, that shoulde make any discoury vnto the North-

    wardes, for that the degrees be so short in those Paralels.

     

     



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