Speculum nauticum A looking-glasse for sea-men. Wherein they may behold, how by a small instrument, called the plain-scale, all nautical questions, and astronomical propositions, are very easily and demonstratively performed. First set down by John Aspley, student in physick, and practitioner of the mathematicks in London. The sixth edition. Whereunto are added, many new propositions in navigation and astronomy, and also a third book, shewing a new way of dialling. By H.P. and W.L. Aspley, John. 1662 Approx. 136 KB of XML-encoded text transcribed from 39 1-bit group-IV TIFF page images. Text Creation Partnership, Ann Arbor, MI ; Oxford (UK) : 2008-09 (EEBO-TCP Phase 1). A75737 Wing A4013 ESTC R229501 99899278 99899278 152809 This keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the Early English Books Online Text Creation Partnership. This Phase I text is available for reuse, according to the terms of Creative Commons 0 1.0 Universal . The text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. Early English books online. (EEBO-TCP ; phase 1, no. A75737) Transcribed from: (Early English Books Online ; image set 152809) Images scanned from microfilm: (Early English books, 1641-1700 ; 2323:2) Speculum nauticum A looking-glasse for sea-men. Wherein they may behold, how by a small instrument, called the plain-scale, all nautical questions, and astronomical propositions, are very easily and demonstratively performed. First set down by John Aspley, student in physick, and practitioner of the mathematicks in London. The sixth edition. Whereunto are added, many new propositions in navigation and astronomy, and also a third book, shewing a new way of dialling. By H.P. and W.L. Aspley, John. H. P. W. L., 17th cent. [4], 64 [i.e. 72] p. : ill., charts printed by W. Leybourn, for George Harlock, and are to be sold at his shop at Magnus Church-Corner, in Thames Street, near London-Bridge, London : 1662. Page 72 misnumbered 64. Reproduction of original in the British Library. Created by converting TCP files to TEI P5 using tcp2tei.xsl, TEI @ Oxford. Re-processed by University of Nebraska-Lincoln and Northwestern, with changes to facilitate morpho-syntactic tagging. Gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. EEBO-TCP is a partnership between the Universities of Michigan and Oxford and the publisher ProQuest to create accurately transcribed and encoded texts based on the image sets published by ProQuest via their Early English Books Online (EEBO) database (http://eebo.chadwyck.com). 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Keying and markup guidelines are available at the Text Creation Partnership web site . eng Dialing -- Early works to 1800. Navigation -- Early works to 1800. Nautical astronomy -- Early works to 1800. 2007-12 TCP Assigned for keying and markup 2007-12 Apex CoVantage Keyed and coded from ProQuest page images 2008-01 John Pas Sampled and proofread 2008-01 John Pas Text and markup reviewed and edited 2008-02 pfs Batch review (QC) and XML conversion Speculum Nauticum . A Looking-Glasse FOR SEA-MEN . Wherein they may behold , how by a small Instrument , called the PLAIN SCALE , all Nautical Questions , and Astronomical Propositions , are very easily and demonstratively performed . First set forth by John Aspley , Student in Physick , and Practitioner of the Mathematicks in London . The Sixth Edition . Whereunto are added , many new Propositions in Navigation and Astronomy , and also a third Book , shewing a new way of Dialling . By H. P. and W. L. LONDON , Printed by W. Leybourn , for George Hurlock , and are to be sold at his Shop at Magnus Church-Corner , in Thames-Street , near London-Bridge , 1662. TO THE WORSHIPFVLL , THE MASTER , WARDENS , & ASSISTANTS OF THE TRINITY HOVSE ; JOHN ASPLEY , IN TESTIMONY OF THE HONOUR HE BEARS TO THE GOVERNOURS & PRACTISERS OF THE ART OF NAVIGATION , DEDICATES THESE HIS FIRST LABOURS . The Printer to the Reader . THis little book having been well accepted of among Sea-men , being the first fruites of Mr. Aspley's Mathematical Studies , hath passed five Impressions , without any alteration ; and so I doubt not might have done still : But because since that time there have been severall bookes put out of this nature , I have procured this to be revised , and severall alterations and additions to be made therein , So that here you have both the old , and a new booke intermingled all in one , with a third part added thereto , concerning Dialling ▪ by a way not formerly published by any . All which I doubt not you will kindly accept of , and receive much delight and profit thereby . Your . G. H. ERRATA . PAge 34 line 26 read 360. Page . 45. l. 8. r. Distance I M. Page 50. line 13. for 14 &c. 〈…〉 which is just the length of the Gnomon . Page . 50 line . 28. for increase , read decrease , Page 52 line 4. r. H A I. line 18. r. point O. Page 57 line 11 r. point L. Also for some lite●all faults we shall desire your Pardon ▪ Speculum Nauticum , OR THE SEA-MANS GLASSE . The First Book . CHAP. I. The Explanation of certain Terms of Geometry . BEing intended in this Treatise of the plain Scale , to declare the manner of projection of the Sphere , in plano , I have thought fitting first , to shew unto you some tearms of Geometry which are necessary for the unlearned to know , ( for whose sake chiefly I write this Treatise ) before they enter into the definition of the Sphere . First therefore I intend to relate unto you , what a point or prick is , and afterward a Line both right and crooked , and such sorts thereof as are appertinent unto the operations and use of this Scale . Punctum , or a point , is the beginning of things , or a prick supposed indivisible , void of length , breadth , and depth : as in the Figure following is noted by the point , or prick A. Linea , or a Line , is a supposed length , or a thing extending it self in length , not having breadth nor thickness , as is set forth unto you by the Line BAD . Parallela , or a Parallel Line , is a line drawn by the side of another line , in such sort that they may be equidistant in all places . And of such parallels , two only belong unto this work of the plain Scale , that is to say , the right lined Parallel , and the circular Parallel . Right lined Parallels are two right lines equidistant one from another , which being drawn forth infinitely , would never touch or meet one another , as you may see in the Figure , where the line H I is Parallel unto the line CE , and the line GF is Parallel unto them both . A circular Parallel is a circle drawn either within or without another circle upon the same center , as you may plainly see by the two circles BCDE , and XVYW . These circles are both drawn upon the center A , and therefore are parallel the one unto the other . There is another kind of Parallel also , which is called a Serpentine Parallel , but because it is not belonging unto the use of this Scale , I will omit it , and so proceed unto the rest . Perpendiculum , or a Perpendicular is a line raised from , or let fall upon , another line , making equal Angles on both sides , as you may see declared in the figure , where in the line AC is perpendicular unto the line BAD , making equal ●ngles in the point A. Diameter circuli , or the Diameter of a Circle , is a right line drawn thorow the center of any circle , in such sort that it may divide the circle into two equal parts , as you may see the line BAD is the Diameter of the circle BCDE , because it passeth thorow the center A , and the two ends thereof do divide the circle into two equal parts , in the two extreams B and D , making the semicircle BCD equal unto the semicircle DEB . Semidiameter circuli , or the semidiameter of a circle is half of the Diameter , and is contained betwixt the center , and the one side of the circle , as the line AD is the Semidiameter of the circle BCDE . This Semidiameter contains 60 degrees of the line of Chords , which we sometimes call the Radius . Semicirculus , or a Semicircle , is the one half of a circle , drawn upon his Diameter , and is contained upon the Superficies , or Surface , of the Diameter , as the Semicircle BCD which is half of the circle BCDE , and is contained above the Diameter BAD . Quadrans circuli , is the fourth part of a circle , and is contained betwixt the Semidiameter of the circle , and a line drawn Perpendicular , unto the Diameter of the same circle , from the Center thereof , dividing the Semicircle into two equal parts , of the which parts , the one is the Quadrant , or fourth part of the same circle . As for example , the Diameter of the circle BCDE is the line BAD , dividing the circle into two equal parts : then from the center A raise the Perpendicular AC , dividing the Semicircle likewise into two equal parts ; so is ABC , or ACD , the Quadrant of the circle BCDE , which was desired . CHAP. II. The manner how to raise a Perpendicular from the middle of a line given . 〈◊〉 first a ground line whereupon you would have a Perpendicular raised , then open your Compasses unto any distance ( so it exceed not the end of your line , ) placing one foot of the said Compasses in the point from whence the Perpendicular is ●o be raised , and with the other foot make a mark in the line on 〈…〉 removing your Compasses unto any other distance that 〈…〉 set one foot thereof in one of the marks , and with the 〈◊〉 foot make an Arch over the middle point , then with the same distance of your Compasses set one foot in the other mark upon the line , and with the other foot make another Arch of a Circle over the middle Point , so that it may cross the first Arch , and from the meeting of these two Arches , draw a right line unto the middle Point , from which the Perpendicular was to be raised , which line shall be the Perpendicular desired . Example , suppose your Base or ground line whereupon a Perpendicular is to be raised be the line FLK , and from L the Perpendicular is to be raised , set one foot of your Compasses in the Point L , and with the other , make the marks G and M on both sides of the point L , the● opening your Compasses wider , set one foot in the point M , and with the other draw the Arch S over the point L , then with the same distance of your Compasses , set one foot in G , and with the other make the Arch R , crossing the Arch S in the point T , then from T draw the line TL , which line is perpendicular unto the line FLK from the point L , which is the perpendicular desired . CHAP. III. To let a Perpendicular fall from any Point assigned , unto the middle of a line . LET the line whereupon you would have a Perpendicular let fall be the line LFK , and the point assigned to be the point T , from whence you would have a Perpendicular let fall upon the line FLK , first set one foot of your Compasses in T , and open your Compasses unto any distance so that it be more than the distance TL , which here we suppose to be the distance TM ; then make in the line FLK the marks G and M , then with your Compasses take the one half of GM , which is the point L , then from L draw a line unto the point T , so the line TL shall be the Perpendicular , which was desired to be let fall from the assigned point T unto the middle of the line FLK . CHAP. IV. To raise a Perpendicular upon the end of a Line . SUppose the line whereupon you would have a Perpendicular raised , be the line FLK , and from the point F a Perpendicular is to be raised : first open your Compasses unto any distance , which here we put to be the distance FG , and set one foot of your Compasses in the point F , and with the other draw the Arch DEG , then set one foot of your Compasses in the point G , and with the other draw the Arch E ; then placing one point of your Compasses in E , with the other draw the Arch DB ; then place your Compasses in D , and with the same distance draw the Arch A , cutting the Arch DB in C , then draw a line from C unto the end of the line FLK , unto the assigned point F , so shall the line CF be a Perpendicular raised from the end of the line FLK , and from the assigned point F. CHAP. V. To let a Perpendicular fall from any point assigned unto the end of a Line . LET the line FLK be the Base or ground line , and from the point I a Perpendicular is to be let fall upon the end of the line at K , first from the assigned point I , draw a line unto any part of the Base , which shall be the line IHM , then find the middle of the line IM , which is at H ; place therefore one foot of your Compasses in the point H , and extend the other unto I , with which distance draw the Arch INK upon the Center H , cutting the Base or ground-line in the point K , then draw the line KI , which line shall be the Perpendicular desired . CHAP. VI. A right Line being given , how to draw another parallel there unto at any distance required . LEt the line given be AB , unto which it is required to draw another right line CD which shall be parallel to the former line AB , and at the distance AC . First open your Compasses to the distance AC , then set one foot in the point A , with the other describe the Arch C ; again , place one foot in B , and with the other describe the Arch D ; Then draw the line CD , so that it may only touch the two Arches C and D , so shall the line CD , so drawn , be parallel to AB , and at the distance required . CHAP. VII . A right line being given , how to draw another parallel thereunto , which shall also pass through a point assigned . LEt AB be a line given , and the point assigned be C : and let it be required to draw another line parallel thereunto , which shall pass through the given point C. NOw I doubt not but you understand the way to let fal , or to raise any manner of Perpendicular line , either from , or upon any part of a line : as also to draw lines parallel one to another at any distance required , therefore now I intend to proceed unto the main point here aimed at , which is , to declare , and make known unto you the several operations performed by the plain Scale , which though it be in use with very few , yet it is most necessary for Sea-men , because all questions in Navigation are thereby easily and plainly wrought . And also all questions in Astronomy ( belonging unto the expert , and industrious Sea-men ) may both speedily and easily be wrought by the same Scale : in regard whereof I have declared in this little Book , that knowledge ( which God hath been pleased to bestow upon me ) concerning the necessary use and practice thereof ; hoping that you will as kindly accept it , as it is freely offered unto your courteous considerations . CHAP. VIII . Of the description of the Scale . The figure of the plane Scale . The second part of the Scale , is the single Chorde of a circle , or the Chord of 90 , and is divided into 90 unequal divisions , representing the 90 degrees of the Quadrant : and are numbred with 10 , 20 , 30 , 40 , &c. unto 90. This Ghord is in use to measure any part or Arch of a circle , not surmounting 90 degrees : The number of these degrees from 1 unto 60 is called the Radius of the Scale , upon which distance all circles are to be drawn , whereupon 60 of th●se Degrees are the Semidiameter of any Circle that is drawn upon that Radius . The third part of the Scale is divided into eight parts , representing the Points or Rumbes of the Mariners Compass ; which in all are 32 points : but upon the Scale there are only S reckoned , which is but one Quadrant or quarter of them , being to be reckoned from the Meridian of North and South both wayes , as you may see more plainly by this figure , representing the order of the points of the Compasse . It is usuall also to have another line placed upon your Scale , to she● you how many leagues make a degree of longitude in every latitude , concerning which you shall have directions in the 14 Chapter following . CHAP. IX . Knowing the course any ship hath made , and the leagues she hath sailed : to find how much she hath raised or depressed the Pole ; and likewise how much she is departed from her first Meridian . The Course is South-west and by South , the leagues sailed are 100 , the difference of the Latitude , and the distance of the Meridians is required . Now you must heedfully observe this point D , for this represents the place where your Ship is , and doth shew both the differencefo the latitude of the place you are in , and also your distance or departure from your first meridian . First for the latitude , you see the line DF , being paralel to the line AB , cuts the Meridian line AF in the point F : So that if you take the distance FA with your Compasses , and apply it to the scale of equal leagues , you shall find it is just 83 leagues , which counting 20 leagues to a degree , makes 4 degrees 9 min. and so much you have altered your latitude by the said course , which degrees and minutes being added to , or substracted from the latitude of the place you came from , according as your course requires , shews you alwaies the true latitude you are in . Likewise from this point D , take with your Compasses the distance DF , and you shall find it by your scale of equal leagues to be 56 leagues , and so much you are departed from your first Meridian to the West-ward ; which when you are near the Equinoctial , where the degrees of longitude are equal to the degrees of latitude , would shew the longitude , by taking 20 leagues for one degree , &c. so it would be two degrees , and 48 min. for your difference of longitude , from y●ur first Meridian AF. But in other places , you must first 〈◊〉 howmany leagues make a degree of longitude about that latitude where you are , and so turn your leagues of distance from the Meridian , into degrees and minutes of longitude , of which more hereafter , Chap. 14. I have been the larger in these two Propositions , because they are ●he first , for the better understanding of all the rest ; and because they are most necessary , for thereupon depends the knowledge of the true Traverse point , and the keeping of your dead reckoning . Now because this cannot alwaies be kept exactly , it is to be corrected by the observation of the latitude , according to this following proposition . CHAP. X. Knowi g the difference of latitude of two places , and the Rumb you have sailed upon , to find the leagues you have sailed , and the difference of Meridians . The Pole depressed four degrees and the Rumb South-West by South or the third from the Meridian , to find your true Traverse point , viz. how far you have sailed , and how much you are departed from your first Meridian . In the first figure DRaw the lines as in the former Chapter , so that AKF may represent the Meridian line , and ACD may represent the third Rumb from the meridian ; then because you have altered your latitude 4 degrees , which make 80 leagues , take 80 leagues with your Compasses out of your Scale , and set them upon the meridian line AF , from A to L : Then keeping the same distance of your Compasses , draw the line LM parallel to AB , ( or else you may erect LM perpendicular to the line AF , in the point L ) and mark where the said LM crosseth the Rumb line ACD , which is in the point M. This point M is the true Traverse point , the leagues sailed are shewed by the line AM , which being measured in the Scale , will be found to be 96 leagues and an half , and the departure from the Meridian is LM , which is 54 leagues . Now by this Proposition ( as I said ) you may correct your dead reckoning ; for suppose by the former proposition you reckon you had sailed 100 leagues upon the ●hird Rumb , then as you see there , you should have been at the point D , and have altered your latitude 83 leagues , and departed from your Meridian 56 leagues ; but now suppose that by a good observation of the latitude , you find that you have altered the latitude onely 80 leagues , from A to L , by drawing this line LM , which crosseth the Rumb or Ships way in M , you may conclude your true Traverse point to be at M , so that you have sailed only from A to M , which is 96 leagues ½ , and departed from your Meridian 54 leagues . So that as you are short of the latitude you reckoned for 3 leagues or 9 min. you are also short of your way you reckoned 3 leagues ½ , and two leagues less in your departure from the Meridian . And this you must account for your true reckoning , being thus corrected . CHAP. XI . By the difference of the latitudes of two places and the distance between their Meridians , to find the Rumb by which you must sail from the one place to the other , and how far it is from the one place to the other ? The difference of latitude between the two places is 4 deg . 9 min. and the distance between the two Meridians is 56 leagues , and it is required to find the Rumb from the one place to the other . IN the former figure draw the quadrant AKCB , then turn your four degrees 9 min. of latitude into leagues , it maketh 83 leagues , which you must place upon the meridian line from A to F. And from the point F draw the line FD parallel to the line AB . Then open your Compasses to the distance of the meridians which is 56 leagues , and set it on the line FD , from F to D. Then lay your Ruler by this mark D and the Centre A , and draw the line ACD . Then mark where this line cuts the quadrant , which is in the point C , and setting one foot of your Compasses in the point C , open the other to K , and keeping your Compasses at that distance CK , measure it upon your Scale , either in the line of Chords , or in the line of Rumbs , you sh ll find it to be in the one 33 deg . 45 min. and in the other just the third Rumb from the meridian . So that the Rumb from A 〈◊〉 D ●s South-west and by South , and the Rumb from D to A is the Rumb opposite thereunto , which is North-east and by North. Then for the distance between the two places in the Rumb , ●et one foot of your Compasses in the one place at A , and open the other to the other place at D , and the length of the line A D ineasured in the Scale of leagues , shews the distance between them to be just 100 leagues . These three ( or rather these six ) Propositions , ( for they are each of them double ) are the most usefull and necessary in the art of Navigation . By the first of these , knowing the point of the Compass you ●ail upon , and judging howmany leagues you have sailed thereon , you know and are able to give a reasonable account where you are , both in respect of latitude and longitude . By the second having a fair observation of the latitude at any time , you may more perfectly know where you are ; and thereby correct your former account . And by this third you may know how to direct your course from any place to your desired haven . So that in effect you need no more , but yet for your better instruction by variety of cases and examples , I shall proceed . CHAP. XII . The difference of Latitude and the lea●●es sailed being given , to find the distanee from the Meridian , and the Rumb you have sailed upon . Sailing 100 leagues between South and West , untill the Pole be depressed 4 deg . 9 min. the distance from the Meridian is demanded , and what Rumb you have sailed upon ? IN the first figure draw the Quadrant AKCB , as in the former Chapters , and then reduce your degrees of latitude into leagues , so 4 deg . 9 min. make 83 leagues , which you must take with your Compasses out of your Scale of leagues , and set them off in this Meridian line from A to F. Then from the point F draw the line FD , parallel to the line AB , which you may do with the foresaid distance of your Compasses . Then open your Compasses unto your distance failed , which is 100 leagues , and setting one foot of your Compasses in the point A , with the other draw the little Arch HG , cutting the line FD in the point D. So the line FD measured in the Scale of leagues , shall shew you the distance from the M ridian , which is 56 leagues , and if you draw the line ACD , it i● the Rumb line upon which you have sailed , and the Arch KC 〈◊〉 ed in the Scale of Rumbs , shews it to be the third Rumb from the Meridian , or South-west by South . CHAP. XIII . To find the distance of any Island from you , that you may discern at two stati n● , knowing the po●ut of the Compasse , the Island beareth unto each of the stations . Suppose , being at Sea you discover an Island bearing North-east off you , which place let it be your first station , and then sailing seven leagues full North you observe the Island to bear full East off you , which let be the second station ; the aemand is to find the distance of the said Island from both the said stations ? IN the second figure , or demonstration , let A be the first Station , and upon the Center A draw the Quadrant ABDE ; Then in regard you found the Island to bear North-East from you , take 4 of your 8 points of the Compass our of the Scale , and place them upon your Quadrant from B to D , then from the Center A by the point D , draw the line ADF , representing the visuall line passing between your sight and the Island , being at the first station A. Then seeng when y●● had sailed 7 leagues North , you observed the Island to bear full East off you , set off the said 7 leagues from A to C , ( reckoning every 10 leag● s of your Scale to be but on● ) and from this point C , which is the second station , draw the line C F parallel to AE , and it will cut the line ADF in the point F : So shall the point F , be the place of the Island desired , and the distance AF , is the distance of the Island from the first station , viz. 9 leagues 90 parts or almost 10 leagues : Likewise the distance from C , to F , is the distance of the Island from the second station , which is just seven leagues . And by this manner of work , you may find the ▪ distance of any Island or head land from you , or you may take the distances of as many places as you will or can see at any two such stations , and by the crossing of their visuall lines , find their position and distances each from other . CHAP. XIV . To find how many leagues , miles , and parts do make one degree of longitude in every latitude . Note , All this while we have been sailing according to the Rules of the plain Chart , which supposith the degrees of longitude to be equal to the degrees of latitude , in all latitudes , but that is very false and erroneous ; it being true onely in places near the Equinoctiall , where every degree of longitude contains 20 leagues , as the degrees of latitude do ; But in places neer the Poles it alt●rs very much , so that in the latitude of 60 degrees , 10 leagues make a degree of longitude : and in other latitudes the degrees of longitude alter , as in this little Table , which shews at what degree and minute of latitude , any nnmber of leagues make a degree of longitude , by which you may divide a Line upon your Scale for your ready use . Leagues in one Degree . 20 00 d 00 m 19 18 11 18 25 50 17 31 47 16 36 52 15 41 25 14 45 34 13 49 27 12 53 08 11 56 38 10 60 d 00 m 9 63 15 8 66 25 7 69 31 6 72 32 5 75 31 4 78 28 3 81 22 2 84 16 1 87 08 Now to return to the Question , and shew you by demonstration how to find how many leagues , miles , and parts , make a degree of longitude in any degree of latitude ? The larger you make your Quadrant , the more exact will the work be , and shew the leagues and miles more exactly , which you may make into a Table , as this following . A Table shewing how many leagues , miles , and hundred parts of a mile make one degree of longitude in any latitude . Latitude Leagues Miles Parts Difference   Latitude Leagues Miles Parts Diffe ence   Latitude Leagues Miles Parts Diff●rence 0 20 0 0 —   30 17 0 96 —   60 10 0 0 — 1 19 2 99 1   31 17 0 43 53   61 9 2 09 91 2 19 2 96 3   32 16 2 88 55   62 9 1 17 92 3 19 2 92 4   33 16 2 32 56   63 9 0 24 93 4 19 2 85 7   34 16 1 74 58   64 8 2 30 94 5 19 2 77 8   35 16 1 15 59   65 8 1 36 94 6 19 2 67 10   36 16 0 54 61   66 8 0 40 96 7 19 2 55 12   37 15 2 92 62   67 7 2 44 96 8 19 2 42 13   38 15 2 28 64   68 7 1 47 97 9 19 2 26 16   39 15 1 63 65   69 7 0 50 97 10 19 2 09 17   40 15 0 96 67   70 6 2 52 98 11 19 1 90 19   41 15 0 28 68   71 6 1 53 99 12 19 1 69 21   42 14 2 59 69   72 6 0 54 99 13 19 1 46 23   43 14 1 88 71   73 5 2 54 100 14 19 1 22 24   44 14 1 16 72   74 5 1 54 100 15 19 0 96 26   45 14 0 43 73   75 5 0 53 101 16 19 0 68 28   46 13 2 68 75   76 4 2 52 101 17 19 0 38 30   47 13 1 92 76   77 4 1 50 102 18 19 0 06 32   48 13 1 15 77   78 4 0 48 102 19 18 2 73 33   49 13 0 36 79   79 3 2 45 103 20 18 2 38 35   50 12 2 57 79   80 3 1 42 103 21 18 2 1 37   51 12 1 76 81   81 3 0 38 104 22 18 1 63 38   52 12 0 94 82   82 2 2 35 103 23 18 1 23 40   53 12 0 11 83   83 2 1 31 104 24 18 0 81 42   54 11 2 27 84   84 2 0 27 104 25 18 0 38 43   55 11 1 41 86   85 1 2 23 104 26 17 2 93 45   56 11 0 55 86   86 1 1 18 105 27 17 2 46 47   57 10 2 68 87   87 1 0 14 104 28 17 1 98 48   58 10 1 80 88   88 0 2 09 105 29 17 1 48 50   59 10 0 90 90   89 0 1 05 104 30 17 0 96 52   60 10 0 0 90   90 0 0 0 105 CHAP. XV. The difference of latitude , and the Rumb or distance sailed being known , to find the distance of the Meridians , and thereby to find the degrees and minutes of the difference of longitude in any latitude . Sailing from the North parallel of 56 degrees and 5 min. latitude , 100 leagues upon the third Rumb from the Meridian ▪ viz. South-west and by South untill I find the Pole is depressed 4 deg . 9 m. and the Meridional distance 56 leagues ; the longitude is desired thereby ? I● the first figure Now to reduce this 56 leagues into degrees of longitude , you must consider from what latitude you have sailed , and to what latitude you are come , viz. from latitude 56 d. 5 m. to 4 deg . 9 min. lesse , which is 51 d. 56 m. and take the middle latitude ( or somewhat more ) between the two places , which in this example falls out to be 54d . 01 m. Then by the Table in the former Chapter , find out howmany leagues and miles in the said middle latitude make one degree of longitude , and you shall find in that Table , that in the latitude of 54 d. there is but 11 leagues , and 2 miles , and 27 parts in one degree of longitude ; Therefore open your Compasses upon your Scale of leagues , to this 11 leagues , 2 miles , 27 parts , and keeping your Compasses at that distance , set one foot of them at 56 leagues in your Scale of leagues , or in the line DF in the figure , ( or upon the like line in your Chart at any time ) either at F or D , and measure howmany times you find that distance either to the end of your Scale coming backward , or in the line DF , for so many degrees is the difference o● longitude , and if any odde part remain , you may proportion i● by your eye , judging it to be a quarter , a third , an half , or any part more or lesse of a degree , which you may either reckon by parts , or 15 , 20 , 30 &c. minutes , Thus this line DF being 56 leagues , opening your Compasses to 11 leagues 2 miles 27 parts , you will find this distance in it , 4 times and 3 quarters ; so that the difference of longitude is 4 deg . 45 min. Or you may reduce it into miles and work by the rule of proportion , so you shall find As 11 leagues , 2 miles , 27 parts , that is 35 miles 27 parts . 35,27 To one degree of longitude in the latitude of 54 d. 01,00 So is 56 leagues , or 168 miles . 168,00 To 4 degrees , 76 parts . 04 76 But if your Scale be large , the other way with your Compasses will give you the degrees and parts of longitude as exactly as you need for most uses . Also if the latitude fall not out in equal parts , you may find out for your odde minutes by proportion , for which purpose I have set the differences between each degree in the Table . So that as one hundred parts or 60 minutes being one degree , to the difference in the Table between the two next degrees ; So the odde hundred parts or minutes of latitude , to the parts and minutes proportional to be allowed . CHAP. XVI . Sailing from the South latitude of 60 degrees , 51 min. and from longitude 25 degrees , 24 min. 99 leagues , upon a South-west course : the latitude and longitude of the second place is demanded . IN the second demonstration , draw the Quadrant ABCDE , as is formerly taught , then in regard you sail South-west , take 4 points of the Compasse from your Scale , and place them from B unto D , then by the point D draw the line ADF , then place your ninety nine leagues upon the line ADF , from A unto F , so shall F be the place of your Ship. Then from F draw the line FC parallel unto AE , cutting the line ABC in C , so shall the distance CA be the leagues you have run South , which is seventy leagues , or 3 deg . 30 minutes , which being added to the latitude from whence you dearted , makes 64 deg . and 21 minutes for the latitude of the second place : then take the distance CF , and apply it unto the line of equal parts , and you shall find it likewise 70 leagues : Then finding the middle latitude 62 degrees 36 minutes in the Table , Chap. 14. you shall find that 9 leagues and 0 miles , and 61 parts , do alter a degree of longitude in that latitude . Then opening the feet of your Compasses to 9 leagues 0 miles 61 parts , in the Scale of equall leagues , and keeping the Compasses at that distance , see howmany times that distance is in the line CF , which is seven times and somewhat above an half , the true difference of longitude being 7 deg . 36 m. which being substracted from the longitude from whence you departed , leaves 17 degrees and 48 minutes for the longitudeof the second place . CHAP. XVII . A Ship sayling from the North Parallel of fifty degrees , having an hundred leagues to sail South-west , and by West , by the way is enforced by contrary winds to sail upon several points of the Compasse , first sailing thirty leagues upon a direct course , then West North-west twenty leagues , then South sixty leagues , the question is to find the latitude of the second place , how far it is to the place whereuuto you are bound , the distance of the Rumb that is betwixt them , the distance that you are from your first Meridian , and thereby the difference of longitude . IN the third demonstration , draw the line AD , and from the point A , raise the perpendicular AB , then open your Compass unto the Radius of your Scale , and place one foot thereof in the center A. and with the other draw the Quadrant BCD , then take three points of the compasse & place them upon the Quadrant from D. unto C , then from the Center A , by the point C , draw the line ACL , 100 Leagues in length , which is the true course you are to saile , Then in regard you sayled thirtie leagues direct , take thirtie leagues from your Scale of equall parts , and place them upon the line AEC , it extends from A unto E : then in regard you turned your Course , West , Northwest , from the Center E , draw the Line EG parallell unto A. D. and again from the center E draw the line EH perpendicular to EG , and parallell to AB , then witn the distance of the Radius , set one foot of your compasses in the center E , and with the other draw the Quadrant GMH , and in regard you sayled West , Northwest , which is two points from the West Northward , take from your Scale two points of the Compass , and place them upon the Quadrant GMH , from G unto M , then from the center E unto the point M , draw the line EFM , then take 20 Leagues with your Compasses from the Scale of equall parts , and place them upon the line EFM , from E unto F , then is your Ship in the point F. Lastly , in regard you run South 60 Leagues from F , draw a Line Parallell unto the Meridian AB , which is the line FI , then take from your Scale of equall parts sixtie Leagues , and place them from F , unto I , then is your Ship in the point I : then last of all is to be found how far it is to the place where unto you were bound , the distance of the Rumb that is betwixt you , the degrees and minutes you have raised the Pole , the distance of departure from the first Meridian , and thereby t●e difference of Longitude : and that you may so doe , first draw the line OIK , Perpendicular unto the line IF in the point I , and with your Compasses opened unto the distance of the Radius , set one foot of your Compasses in the Center I , and with the other draw the Quadrant KNF , then in regard your ship is in the point I , and the place whereunto you are bound is the point L , therefore from I , thorow the point L draw the line ILN , cutting the Arch KNF , in the point N , therefore let IL , be the Leagues you have unto the place whereunto you are bound , which is fortie one Leagues and a halfe , and the Rumb the distance KN , which is West , and by North , and three degrees unto the Northward , so likewise is the line AO , the number of Leagues you have run due South , which is sixtie eight Leagues and one mile , or three degrees and twenty five minutes , which being taken from fiftie degrees , the parallell from which you departed , leaves fortie six degrees and thirtie five minutes for the Parallel you are in . Last of all , shall the line IO , be the Leagues that you have departed your first Meridian , which are fortie two leagues and one mile , Then take the middle latitude which is fortie eight degrees seventeen minutes and in the Table chap. 14 you shall find that thirteen Leagues 0. mile , 92 parts , do answer unto a degree of Longitude in that Parallell ; then setting one foot of your Compasses in thirteen Leagues , and ninety two parts , extending the other to the beginning of the Scale , keeping the Compasses at that distance , turn them over the line I O , and you shall find it contains that distance three times and almost a quarter , So the difference of longitude is three degrees eleven minutes . CHAP. XVIII . Two Ships departing from one Parallel , and Port , the one in sayling eight Leagues betwixt the North , and the West , hath raised the Pole two degrees , the other in sailing a hundred Leagues betwixt the North , and West , hath raised the Pole four degrees , I demand by what Rhumbs the said Ships have sailed , and the Rhumb and distance that is betwixt them ? IN the fourth Demonstration , draw the Quadrant ABCDE , then in regard the first Ship hath raised the Pole two degrees , which is fortie leagues , take fortie Leagues off your Scale , and applie them unto the Meridian line AGL , from A unto G : then from the point G , draw the line GF , parallel unto AB , then opening your compasses unto 80 Leagues , set one foot in the Center A , with the other make a marke in the line GF , which will be at F , so shall F be the place of the first ship ; the second Ship hath raised the Pole four degrees , which is 80 Leagues , therefore place 80 leagues upon the Meridian line AGL , from A unto L , and from the point L draw the line LM , parallel unto GHF , then open your Compasses unto the distance of a hundred leagues , which are the Leagues the second ship did run , and set the foot of your Compasses in the Center A , and with the other make a mark in the line LM , which will be at M , then draw the line MA , which is the course of the second Ship , and the line FA , is the course of the first ship , then from F let a Perpendicular fall , being Perpendicular to the line GF , which is the line FK , then opening your Compasses unto the Radius of your Scale , set one foot in the Center F , and with the other draw the Quadrant HIK , likewise from F , the place of the first Ship , draw a line by the point M , the place of the second , cutting the Quadrant KHI , in I , so let IK , be the course that is betwixt them , that is , if you will saile from the first ship unto the second , you must saile North and by East , and one and fortie minutes to the Eastward , likewise let F M , be the distance that is betwixt them , which in this Demonstration is fortie Leagues , two miles , so shall BC , be the course of the first ship from the West Northward , wh ch here is found to be thirtie degrees and one minut from the West Northward , or Northwest by West , and three degrees and fortie four minutes to the west ward . Lastly the Arch ED , is in the distance of the course that the second Ship made from the North Westward , which is found by this Demonstration to be Northwest and by North , and three degrees five minutes to the Westward . CHAP. X●X . Two Ships departing from one Parallell and Port in the Parallell of 47 deg . 56 min. the first in sayling 80 leag . betwixt the North and West , hath raised the Pole two degrees , I demand by what course the second ship must runne , and how much she shall alter in her first Meridian or longitude , to bring her selfe 40. leagues and two miles North and by East , and 41. minutes to the Eastward of the first ship ? IN the fourth Demonstration draw the Quadrant ABCDE , then multiplie your two degrees you have altered your latitude by twentie and it maketh fourtie Leagues ; which fourtie Leagues set upon the line AEL , from A unto G , then from the point G draw the line GF , parallel unto AB , then open your Compasses unto the distance of 80 Leagues , which are the Leagues your first ship did runne , and place one foot of your Compasses in the Center A , and with the other make a marke in the line GF , which will be at the point F , then from the Center A unto the point F draw the line AF , representing the distance of the Course of the first Ship 80 leagues : Then from F let fall a Perpendicular FK , and upon the Center F , with the Radius of the Scale draw the Arch HIK , Then in regard you must bring the second ship North and by East , and 41 minutes Eastward of the first ship , take 11 degrees 56 minutes from your Scale of Chords , and place them from Kunto I , upon the quadrant KIH . Then from F draw the line IF , and upon the line , FI , place the distance that you must bring the second ship from the first ( which is fourty leagues and two miles ) from F unto M. So is M the place of your second ship . Then from M draw the line ML parallel unto FG , cutting the line AGL in L , then draw the line MA , cutting the Quadrant BDE in D. So shall the Arch DE be the course that the second ship must run , to bring her self fourty leagues and two miles North and by East , and 41 minutes East of the first ship . Then to know what you have altered the latitude , first take the distance LA and apply it unto the Scale of equall parts , and you shall find it to be 80 leagues , which is just 4 degrees , which you have altered your latitude , or Poles elevation : which 4 degrees added unto the latitude you depar ed from , it makes 51 degrees 56 min. for the latitude that your second Ship is in , then take the distance LM and apply it to the Scale , it gives 60 leagues ; then open your Compasses unto the distance of the middle latitude , which is 40 deg . 5● min. of the Chord , and apply it unto the Table of longitudes , and it gives 12 leagues , and 2 miles , and 62 parts , to alter one degree of longitude in that Parallel : Then set one foot of your Compasses in 12 leagues 2 miles , and 62 parts , and open the other to the beginning of the line , and with that distance measure the line L M , being 60 leagues , and you shall find that it is contained there in four times and two thirds , so the longitude is 4 degrees 40 minutes . CHAP. XXI . Of the Ebbing and Flowing of the Sea , aud of the Tides , and how to find them in all places . A generall Table for the Tides in all places . The Moons age . Hours and minutes to be added . Hours and minutes to be added .   The Moons age . Hours and minutes to be added : Hours and minutes to be added : Daies . Degrees : Minutes :   Daies . Degrees : Minutes : 1 0 48   16 0 48 2 1 36   17 1 36 3 2 24   18 2 24 4 3 21   19 3 12 5 4 0   20 4 0 6 4 48   21 4 48 7 5 36   22 5 36 8 6 24   23 6 24 9 7 12   24 7 12 10 8 0   25 8 0 11 8 48   26 8 48 12 9 36   27 9 36 13 10 24   28 10 24 14 11 12   29 11 12 15 0 0   30 0 0 The use of the Table of the Tides . FIrst it is to be understood , that by the swift motion of the first Mover , the Moon and all the rest of the Stars and Planets , are turned about the World in four and twenty hours , upon which swift motion of the Moon , the daily motions of the Sea , do depend , which motion of the Sea falleth not out alwaies at one hour , the reason thereof is , because of the swift motion of the Moon in regard she goeth almost thirteen degrees in four and twenty hours , and the Sun moveth scarce one degree , which gives every day twelve degrees , that the Moon cometh slower to any point in the Heaven than the Sun : which twelve degrees makes fourty eight minutes of time for the difference of every full Sea , according unto the middle motion of the Moon , which difference is here set down in this Table for every day of the Moons age . Therefore if you would know the full Sea at any place in the World , first you must know at what hour it is full Sea at the new or full Moon ; which hours and minutes keep in mind , then seek the age of the Moon as is before taught , and with the number of her age enter this Table , under the Title of the Moons age , and having found her age in the Table , against it you shall find the hours and minutes which are to be added unto the time that the Moon maketh full Sea in any place , and the whole number of hours and minutes is the time that the Moon maketh full Sea in that place upon the day desired . As for example , I desire to know the full Sea at London Bridge upon the 13 of July 1624. the age of the Moon being found as before , is eight daies , then in the Table I find eight daies , and against it 6 hours , and 24 minutes , which being added unto 3 hours , the full Sea upon the change day gives 9 a clock 24 minutes for the time at the full Sea upon the 13 day of July 1624. THE SEA-MANS GLASSE . The Second Book . VVherein is declared the Definition of the Sphear , a Description of the six great Circles , and also of the four lesser Circles , last of all , certain Questions Astronomicall , performed by the said Scale . CHAP. I. Of a Sphear , and the Circles thereof . The figure of the plaine Scale . A Sphear according to the Description of Theodosius , is a certain solid Sup● ficies , in whose middle is a Point , from which all lines drawn unto the Circumference are equall ; which Poi●● is called the Center of the Sphear , by which C●●●er a right Line being drawn , and excending himself on either side unto that part of the Circumference whereupon the Sphear is turned , is called Axis Spherae , or the Axle-tree of the World. A Sphear accidentally is divided into two parts , that is to say , in Sphaeram rectam & Sphaeram obliquam . Sphaera recta , or a right Sphear , is onely unto those that dwell under the Equinoctiall , Quibus neuter Polorum magis altero elevatur : that is , to whom neither of the Poles of the World are seen , but lie hid in the Horizon . Sphaera obliqua , or an oblique Sphear , is unto those that inhabit on either side of the Equinoctial , unto whom one of the Poles is ever seen , and the other hid under the Horizon . The Circles whereupon the Sphear is composed are divided into two sorts : that is to say , in Circulos majores & minores . Circuli majores , or the greater Circles , are those that divide the Sphear into two equall parts : and they are in number six , viz. the Equinoctial , the middle of the Zodiack , or the Ecliptique line , the two Colures , the Meridian , and the Horizon . Minores vero Circuli , or the lesser Circles , are such as divide the Sphear into two parts , unequally , and they are four in number ; as the Tropick of Cancer , the Tropick of Capricorn , the Circle Artike and the Circle Antartike . CHAP. II. Of the six greater Circles . I. THE Equinoctial is a Circle that crosseth the Poles of the World at right Angles , and divideth the Sphear into two equall parts , and is called the Equinoctial , because when the Sun cometh unto it , ( which is twice in the year , viz. In principio Arietis , & Librae , that is , in March and September ) the daies and nights are equal thoroughout the whole World , whereupon it is called Equator diei & noctis , the equall proportioner of the day and night artificiall : and in the figure is described by the line CAE . II. The Meridian is a great Circle passing thorow the Poles of the World , and the Poles of the Horizon , or Zenith point over our heads ; and is so called , because that in any time of the year , or in any place of the World , when the Sun ( by the motion of the Heavens ) cometh unto that Circle , it is noon , or twelve of the Clock . And it is to be understood , that all Towns and places that lie East and VVest one of another , have every one a severall Meridian : but all places that lie North and South one of another , have one and the same meridian . This Circle is declared in the figure following by the Circle BCDE . IV. The two Colures , Colurus Solstitiorum , or the Summer Colure , is a Circle passing by the Poles of the World , and by the Poles of the Ecliptick , and by the head of Cancer and Capricorn , whereupon , the first scruple of Cancer , where the Colure crosseth the Ecliptick Line , is called Punctus solstitiae aestivalis , or the point of the Summer Solstice : to which place when the Sun cometh , he can approach no nearer unto our Zenith , but returneth unto the Equator again . Arcus vero Coluri , The Ark of the Colure contained betwixt the Summer Solstice and the Equator , is called the greatest declination of the Sun , which Ptolomy found to be 23 degrees , 31 minutes : but by the observation of Copernicus it was found to vary , for ●e found the declination sometimes to be 23 degrees 52 minutes , and in the processe of time to be but 23 degrees 28 minutes . And in these our daies ( by the observation of Ticho de Brahe , and that late famous Mathematician , Mr. Edward Right ) it is found distant from the Equinoctiall 23 degrees , 31 minutes , 30 seconds . V. The other Colure passeth by the Poles of the World , & by the first point of Aries and Libra , whereupon it is called Colurus distinguens Equinoxia . These two Colures do crosse each other at right Angles in the Poles of the world , whereupon these , verses were made . Haec duo Solstitia faciunt Cancer Capricornus , Sed noctes aequant Aries & Libra diebus . CHAP. III. Of the four lesser Circles . THe Sun having ascended unto his highest Solstitial Point doth describe a Circle , which is the nearest that he can approach unto the North Pole , whereupon it is called Circulus Solstitii aestivalis , the Circle of the Summer Solstice , or the Tropick of Cancer , and is noted in the figure before , by the line H Y I. The Sun also approaching unto the first scruple of Capricornus , or the Winter Solstice , describeth another Circle , which is the utmost bounds that the Sun can depart from the Equinoctiall Line towards the Antartike Pole , whereupon it is called Circulus solstitii hyemalis , sive Tropicus hyemalis , vel Capricorni : the Circle of the Winter Solstice , the VVinter Tropick , or the Tropick of Capricorn , and is described in the figure by the line GXF. So much as the Ecliptick declineth from the Equinoctiall , so much doth the Poles of the Ecliptick decline from the Poles of the VVorld , whereupon the Pole of the Ecliptick , which is by the North Pole of the VVorld , describeth a certain Circle as it passeth about the Pole of the VVorld , being just so far from the Pole as the Tropick of Cancer is from the Equator , and it is the third of the lesser Circles , and is called Circulus Arcticus , or the Circle of the North Pole , and is described in the Diagram , in the second Chapter by the line PO. The fourth and last of the lesser Circles is described in like manner , by the other Pole of the Ecliptick , about the South Pole of the world , and therefore called Circulus Antarcticus , the Antarctick Circle , or the Circle of the Antarctick or South Pole , and is demonstrated in the former figure , by the line NM . CHAP. IV. Definitions of some peculiar terms fit to be known by such as intend to practice the Art of Navigation or Astronomy . THe Zenith is an imaginary point in the Heavens over our heads , making right Angles with the Horizon , as the Equinoctiall maketh with the Pole. The Nadir is a prick in the heavens under our feet , making right Angles with the Horizon under the earth , as the Zenith doth above , and therefore is opposite unto the Zenith . The declination of the Sun is the Ark of a Circle contained betwixt the place of the Sun in the Ecliptick , and the Equinoctiall , making right Angles with the Equinoctiall . But the declination of a Star is the Ark of a Circle let fall from the Center of a Star , perpendicularly unto the Equinoctiall . The Latitude is the Ark of a Circle contained betwixt the Center of any Star , and the Ecliptick Line , making right Angles with the Ecliptick , and counted either Northward , or Southward , according to the scituation of the Star , whether it be nearer unto the North or South Pole of the Ecliptick . The Latitude of a Town or Countrey , is the height of the Pole above the Horizon , or the distance betwixt the Zenith and the Equinoctiall . The Longitude of a Star is that part of the Ecliptick which is contained betwixt the Stars place in the Ecliptick , and the beginning of Aries , counting them from Aries according to the succession or order of the signes . The Longitude of a Town or Countrey are the number of degrees , which are contained in the Equinoctiall , betwixt the Meridian that passeth over the Isles of Azores , ( from whence the beginning of longitude is accounted ) East wards , and the Meridian that passeth over the Town or Country desired . The Altitude of the Sun or Star is the Arch of a Circle , contained betwixt the Center of the Sun , or any Star , and the Horizon . The Amplitude is that part of the Horizon which is betwixt the true East or West points , and the point of the Compasse that the Sun or any Star doth rise or set upon . Azimuth's are Circles , which meet together in the Zenith , and crosse the Horizon at right Angles , and serve to find the point of the Compasse , which the Sun is upon at any hour of the day , or the Azimuth of the Sun or Star , is a part of the Horizon contained betwixt the true East or West point , and that Azimuth which passeth by the Center of the same Star to the Horizon . The right ascension of a Star is that part of the Equinoctiall that riseth or setteth with the Star , in a right Sphere : or in an oblique Sphere , it is that portion of the Equinoctiall , contained betwixt the beginning of Aries , and that place of the Equinoctiall , which passeth by the Meridian with the Center of the Star. The oblique ascension is a part of the Equinoctiall , contained betwixt the beginning of Aries , and that part of the Equinoctiall that riseth with the Center of a Star , in an oblique Sphere . The difference ascensionall , is the difference betwixt the right and oblique ascension : or it is the number of degrees contained betwixt that place of the Equinoctiall that riseth with the Center of a Star , and that place of the Equinoctiall that cometh unto the Meridian , with the Center of the same Star. Almicanterahs are Circles drawn parallel unto the Horizon , one over another , untill you come unto the Zenith : these are Circles that do measure the elevation of the Pole , or height of the Sun , Moon , or Stars above the Horizon , which is called the Almicanter of the Sun , Moon , or Star : the Ark of the Sun or Stars Almicanter , is a portion of an Azimuth contained betwixt that Almicanter which passeth thorow the Center of the Star , and the Horizon . QUESTIONS ASTRONOMICAL , performed by the plain Scale . CHAP. V. The true place of the Sun being given , to find his declination . The Sun being in the head of Taurus , his declination is desired . BY the seventh Demonstration , draw the line AD , then upon the Center A raise the Perpendicular AB , then opening your Compasses to the Radius of your Scale , place one foot in the Center A , and with the other draw the Quadrant BCD , then opening your Compasses unto the greatest declination of the Sun , place it upon the Quadrant , from D unto K , then from the point K draw the line KH , parallel to DA , cutting the line AB in H , then with the distance AH draw the small Quadrant GEH , and in regard the Sun is in the head of Taurus , which is 30 degrees from the beginning of Aries , let AD be the Equator , and D the beginning of Aries , DC 30 degrees , or longitude of the Sun , then from the point C draw the line CA , cutting the Quadrant GEH in E , then from E draw the line EI parallel to AD , cutting the Quadrant BCD in I , so shall the Arch ID be the declination of the Sun desired , which in this demonstration is found to be eleven degrees , and thirty one minutes . CHAP. VI. The declination of the Sun , and quarter of the Ecliptick that he possesseth , being given , it is desired to find his true place . The Declination is 10 deg . 31 min. the first quarter that he possesseth , is betwixt the head of Aries and Cancer . FIrst , by the seventh Demonstration , draw the Quadrant ABCD , as is taught in the former Chapter , then set the greatest declination of the Sun upon the Chord from D unto K , which is 23 deg . and 31 min. then from K draw the line KH parallel unto the Equator DA , cutting the line BA in the point H. So shall HA be the sign of the Suns greatest declination , then with the distance AH draw the Quadrant GEH , then from D upon the Quadrant DBC set the declination of the Sun , which is 11 degrees 31 minutes from D unto I , then draw the line IE parallel unto AD , cutting the Quadrant GEH in E. Then from the Center A by the point E , draw the line AEC , cutting the Quadrant BCD in C. So shall the Ark CD be the distance of the sun from the head of Aries , which is here found to be just 30 degrees , which is in the beginning of Taurus . CHAP. VII . By the elevation of the Pole , and declination of the sun , to find the amplitude of the sun , or his distance of rising , or setting from the true East or West point . The elevation of the Pole is 51 deg . 32 min. the declination of the sun is 14 deg . 52 min. North. BY the eight Demonstration , first draw the line BD , then upon the Center A draw the Circle BCDE , then from A raise the Perpendicular CAE , then is your Circle divided into four equall parts : then suppose the elevation of the Pole to be 51 degrees , 32 minutes , which must be placed upon the Circle , from D unto F , then from the point F , by the Center A , draw the line FAG , representing the Pole of the World , F being the North Pole , and G the South Pole , then substract 51 deg . 32 min. from 90 deg . and the remainder is the height of the Equinoctiall , which is 38 deg . 28 min. which must be placed upon the Circle from the Horizon B , unto the point I , then from I , by the Center A , draw the line IAH , representing the Equinoctiall Circle . Then from I unto M set the declination of the Sun , being here supposed 14 deg . 52 minutes North , then from the point M draw the line , or Parallel of declination MTN , parallel unto the Equator I A H , cutting the Horizon BD in T , then from T raise the perpendicular TV , cutting the Circle BCDE in V , so shall the distance CV be the true amplitude of the sun desired , which here is found to be 24 deg , 21 minutes North. CHAP. VIII . By the Amplitude of the Sun , to find the variation of the Compasse . HAving found the Amplitude of the Sun by the last Chapter , first observe with a Compasse , or rather with a Semicircle , upon what degree and minute the Sun riseth or setteth , beginning to reckon from the East or West , and ending at the North or South at 90 degrees : and when you have diligently observed the Magneticall rising or setting , by the Semicircle , or by some other like fitting Instrument : and also the true Amplitude found , as is declared in the last Chapter , the difference of these two Amplitudes , is the variation of the Compasse : But when the Sun riseth upon the same Degree of the Compasse , as is found by the Scale , the variation is nothing , but the Needle pointeth directly unto the Poles of the World , which by M. Mulinux was affirmed to be at the Westernmost part of S. Michaels , one of the Islands of the Azores , from whence he will have the Longitude reckoned . Secondly , when the Sun is in the Equinoctial Circle , where he hat● no Amplitude , look what distance the Compasse maketh the Sun to rise from the East or West of the Compasse , the same distance is the Compasses variation , from the North or South . Thirdly , if the Sun rise more to the South of the Compasse , or setteth more to the North of the Compasse , than is shewed by the Scale , the difference betwixt the Amplitude given by the Scale , and the Amplitude given by the Needle , is the variation of the Compasse from the North Westward . Fourthly , if the Compasse sheweth the Sun to rise more Northward , or set more Southward , than is shewed by the Scale , the difference is the variation of the Compasse , from the North Eastward . Fifthly , if the Scale shew the Amplitude of the Sun rising Southerly , and the Compasse shew it to be Northerly , adde both the Amplitudes together , and they shew you the variation Westernly . CHAP. IX . The place of the sun being given , to find his declination , by a whole Circle . The suns place is the tenth degree of Taurus . ACcording unto the eighth Demonstration , first draw the Circle BCDE , then draw the Horizon BAD , and then the Equinoctial IAH , as is before taught : and then the Tropick of Cancer KL , twenty three degrees and a half from the Equinoctial : then draw the Tropick of Capricorn PO , of like distance from the Equinoctial , and after from K to O draw the Ecliptick line KAO. And when you have thus laid down the Sphere , suppose the Sun to be in the tenth degree of Taurus , at which time his declination is desired . And in regard the Sun is more near unto the Tropical point Cancer , than unto Capricorn ; first find how many degrees he is from the Tropick of Cancer , and you shall find him to be 50 degrees ; therefore take with your Compasses 50 degrees from the Chord , and apply it from the Tropical point Cancer at K , unto V , upon one side , and unto P on the other side : then draw the Line VP , cutting the Ecliptick KO in the point R , then from R draw the Line MRN parallel unto the Equinoctial IAH , and cutting the Quadrant BC in the point M. So shall the arke MI be the declination of the Sun desired , which being applyed unto your Scale , gives you 14 deg . and 52 minutes . CHAP. X. The elevation of the Pole , and declination of the sun given , to find his height in the vertical Circle . The Pole is elevated 51 degrees 32 minutes , the declination of the sun is 14 degrees 52 minutes North , his height in the Verticall Circle is found as followeth . FIrst , according unto the former Chapter , draw the Circle BCDE , then the Horizon BAD , and after the verticall line CAE , then the Axis of the World FG , and likewise the Equator IAH , this being done , place the declination of the Sun 14 degrees 52 minutes , upon the Circle from I unto M , and also from H unto N , then draw the line MN , cutting the line CAE in S , then from S draw the line SVV , parallel unto the Horizon BAD , cutting the Meridian Circle BCDE in VV : so shall the distance DVV be the height of the Sun in the vertical Circle , for the time demanded , which by this proposition is found to be 19 degrees and 8 minutes . CHAP. XI . The elevation of the Pole , and the Amplitude of the sun , being given , to find the declination . The elevation of the Pole is 51 degrees 32 minutes , the suns amplitude is 24 degrees 21 minutes , the declination is found as followeth . FIrst , as in the eight demonstration , upon the Center A , draw the Circle BCDE , then draw the Line BAD , representing the Horizon : dividing the circle into two equall parts then draw the Line CAE , perpendicular to BAD , representing the East and VVest points of the Compasse , then placing the elevation of the Pole 51 degrees and 32 minutes , from D unto F , from F , by the center A ▪ draw the Line FAG , which let be the Pole or Axletree of the world , then from B unto I , and from D unto H , set the complement of the Poles elevation : which shall represent the Equinoctiall , in regard it maketh right Angles with the Pole of the world , in the center A. Then from C unto V place the amplitude of the Sun , which is 24 degrees and 21 minutes : then from V let fall the perpendicular VT , cutting the Horizon BAD in the point T , then from the point T , draw the Line MTN parallel unto the Equinoctiall IAH , and cutting the Circle BCDE in the points , M and N , so shall the distance , M , or HN , be the declination of the Sun , which was desired : which being applied unto your Scale , gives you fourteen degrees and fifty two minutes . CHAP. XII . The elevation of the Pole , the declination of the Sun , and hour of the day being given ▪ to find the Almicanter . The elevation of the Pole is thirty degrees , the declination of the Sun is twenty degrees North , the hour is nine in the morning , at which time the Almicanter is found , as followeth . BY the ninth demonstration , first upon the Center A , draw the Circle BCDE , then draw the line BD for the Horizon , then place your Poles elevation , which is thirty degrees , upon the Circle from D unto R , then from R by the center A , draw the Line RAS , representing the Axis of the World , then from B unto F place the complement of the Poles elevation , which is ●0 degrees , and from the point F , by the Center A , draw the line FAH , representing the Equinoctial line , and then set the declination of the Sun from F unto L ▪ and from L draw the Line LPO parallel unto the Equator FAH , cutting the Axis of the World in the point P , then set one foot of your Compasses in the point P , and extend the other either unto L or unto O , and with the same distance of your Compasses , upon the Center P , draw the circle LNOQ , which is called the hour circle : so shall L be the point of twelve a clock at noon , N the place of six a clock after noon , O the place of twelve a clock or midnight , and Q the place of six a clock in the morning : Every one of the four quarters must be divided into six equall parts , or hours , making the whole Circle to contain twenty four parts , representing the twenty four hours of the day and night , then in regard the hour of the day was nine of the clock , which is three hours before noon , take three of those twenty four hours , and place them upon the circle LNOQ , from the Meridian point L unto K , the nine a clock point in the morning , and unto M the point of three a clock after noon , then draw the line MK , cutting the parallel of the Sun LO in the point I , then from I draw the line IG parallel unto the Horizon BAD , which shall cut the Meridian Circle BCDE in the point G , so shall the distance of G and B be the Almicanter the Sun , which was desired , which in this demonstration is found to be fourty eight degrees and eighteen minutes . CHAP. XIII The elevation of the Pole , the Almicanter , and declination of the Sunne , being given , to finde the houre of the day . The elevation of the Pole is thirty degrees , the declination of the Sun , is twentie degrees , the Almicanter of the Sun , is fortie eight degrees , and eighteene minutes , the houre of the day is found as followeth . FIrst , as in the ninth demonstration , upon the Center A , draw the Circle BCDE , then draw the Diameter BD , representing the Horizon , then from D unto R , set 30 degrees , the elevation of the Pole , then from R unto the point A , draw the line RAS , representing the Pole of the World , then draw the line FAH , crossing the Pole in A , at right Angles , cutting the Meridian circle in F , then from F , set twenty degrees , the declination of ●he Sun unto L , and then from the point L , draw the line LPO , representing the parallell of the Sun , and cutting the Pole of the World in P , then placing one foot of your Compasses in P , extend the other unto L , with which distance of your Compasses , draw the hour Circle LNOQ , then from the Horizon at B , place the Suns Almicanter : ( which is fortie eight degrees , and eighteen minutes ▪ ) upon the Quadrant BGL , from B unto G , then from the point G , draw the line G● parallel unto the Horizon BAD , cutting the Line LO , in I , then from the point I , draw the line KIM , parallell to the Pole of the World QAN , cutting the Circle LNO , in M , then let LN , be divided into six houres , whereof LM , are there : whereupon I conclude , that is is three houres from noon , that is , at nine a clock in the morning , or three in the after noon . CHAP. XIV . The Latitude of the place , the Declination of the Sun , and the Altitude of the Sun being given , to finde the Hour of the day : By a n●w way differing from that in the former Chapter .   deg . min.   deg . m The Suns Altitude is 48 18       The Lat●ude of the place is 30 00 its Comple . 60 00 The Suns declination is 20 00 N. 70 00       Sum 130 00       difference 10 00 The Complement of any arch lesse then 90 degrees , is so much as the arch wants of 90 degrees , as the Complement of 20 degrees is 70 degrees , &c. FIrst , finde the sum and difference of the Complement of the Suns declination , and the Complement of the Latitude , as above is done , where the sum is 130 deg . and the difference 10 deg . Then your Compasses being opened to the Radius of your line of Chords : describe the Semicircle ABC , and divide it into two Quadrants by the perpendic●lar BD , then out of your line of Chords ; take 48 deg . 18 min. the Suns Altitude , and set it from B to E , and draw E F parallel to B D : Then from your line of Chords take 130 deg . the sum , and set it from A to G , ( or its Complement to 180 deg . which is 50 deg . from C to G ) and draw the line GH also parallel to BD. Again , out of your line of Chords , take 10 deg . ( which is the difference ) and set that distance from A to K , and draw K L parallel to EF or BD. This done , take with your Compasses the distance from F to H , and seting one foot in A , with the other describe the Arch MP , likewise take the distance from F to L , and seting one foot in C , with the other describe the arch NQ . Lastly draw the streight line PQ ▪ which only touching the two former arkes will cut the line AC in O , Upon the point O , therefore , erect the perpendicular OR , cutting the Semicircle in R , so will CR being measured upon your line of Chords , give you the degrees of the Sun from the South part of the Meridian , which here you will finde to be 45 degrees , which make 3 hours , allowing 15 degrees for an hour , for 15 degrees make one hour , and one degree makes 4 minuts of an hour , so that it is either 9 of the clock in the morning , or 3 in the afternoon . CHAP. XV. The Almicanter , or height of the Sun being given , to finde the length of the right shadow . The Almicanter is 45 degrees . ACcording unto the tenth Diagram , draw the line AF , and upon the center A , raise the perpendicular AC , then upon the center A , draw the Quadrant CDF , then suppose the height of your Gnomon , or substance yelding shadow be the Line , AB , which is to be divided into 12 equall parts , which Gnomon , I have here made just 12 degrees of the equall Leagues of the Scale , then from B , to the top of the Gnomon draw the Line BE , parallel unto AF , then set the Almicanter which is fortie five degrees from F , unto D , and from the point D , draw the Line DA , cutting the Line BE in the point G , so shall BG , be the length of the right shadow desired , which here is found to be fourteen degrees and eighteen minutes , which is but just the length of your Gnomon , and 2 / 12 and ⅓ of a twelfe over : Note that the right shadow , is the shadow of any poste , staffe , or steeple , that standeth at right Angles with the Horizon , the one end thereof respecting the Zenith of the place , and the other the Naedir . CHAP. XVI . The Almicanter , or height of the Sun being given , to finde the length of the contrary shaddow . The Almicanter given is 70 deg . BY the verse or contrary shadow , is understood the length of any shadow , that is made by a staffe or Gnomon , standing against any perpendicular wall , in such a manner that it may l●e parallel unto the Horizon , the length of the contrary shadow , doth increase as the Sun riseth in height , whereas contrariwise the right shadow doth increase in length , as the Sun doth increase in height : the way to finde the verse shadow is as followeth . First , draw your Quadrant as is taught in the last Chapter , wherein let AB , be the length of the Gnomon , likewise from B , draw the line BE , parallel unto AF , as before , then set your Almicanter from C upon the Quadrant which is given to be seventie degrees and it will extend from C unto H , then from the point H draw the line HA , cutting the line BE , in the point K , so shall KB , be the length of the contrary shadow , which here is found to be thirtie four degrees and eight minutes , or twice so long as your Gnomon , and ●0 / ●2 about ½ part of a twelfth more . CHAP. XVII . The latitude of the place , the Almicanter , and declination of the Sun being given , to find the Azimuth . The latitude of the place is fiftie one degrees , thirtie minutes , the declination of the Sun twenty degrees North , the Almicanter thirtie eight degrees thirtie minutes , the true Azimuth of the Sun is desired . FIrst as in the eleventh Demonstration upon the Center A , draw the Circle BCDE , then draw the Diameter BAD ▪ and from D unto F , set the Elevation of the Pole , which is one and fiftie degrees , and thirtie minutes , whose complement is eight and thirtie degrees and thirtie minutes , which must be placed from B unto H , then from H , draw the line HAL , representing the Equinoctial line , and from F , draw the line FAG , representing the Pole of the World , then from H unto P , and from I unto Q , set the declination of the Sun , which is twentie degrees , and by those two points draw the line PQ , for the Parallel of the Suns declination ; then upon the Circle from B unto H ▪ set the Suns Almicanter , thirtie eight degrees , and thirtie minutes , then from H , draw the line HR ▪ parallel unto the Horizon cutting the Suns parallel POQ in O , then draw the Line TVAE Perpendicular unto the line BAD , in the Center A , and cutting the line HVR , in V , then seting one foot of your Compasses in the point V , extend the other unto R , and with the same distance draw the Semicircle HLR , then draw the Concentricke Circle upon the Radius of the Scale MTN , and where the Line POQ , and the line MON do meet in the point V , raise the Perpendicular OL , cutting the Semicircle HLR in L , then lay the Scale from the Center A to the point L , and draw the line LK , cutting the Semicircle MTN , in K , so shall M K , be the true distance of the Sun from the East , or West point Southward , or the Suns true Azimuth , which is here found to be seventie two degrees , and fortie minutes from the South part of the Meridian . CHAP. XVIII . The Latitde of the place , the Declination of the Sun , and the Altitude of the Sun being given to finde the Azimuth : By a new way differing from that in the former Chapter .   deg . min. S. deg . m. The Suns Declination is 20 00       The Latitude of the place is 51 30 its Comple . 38 30 The Suns Altitude is 12 00   78 00       Sum 116         difference 39 30 HAving found the sum and the difference of the complement of the Suns Altitude , and the complement of the Latitude as above is expressed where you finde the Sum of them to be 116 deg . 30 min. and their difference 39 deg . 30 min. Secondly , take 116 deg . 30 min. the sum out of your line of Chords , and set it from C to G , and draw the line GK parallell D to B , Thirdly take 39 deg . 30 min. the difference , out of your line of Chords , and set it from C to H , and draw the line HL parallell also to BD. Fourthly Take in your compasses the distance from F to K , and setting one foot in A , with the other describe the arch S. Fifthly , Take the distance from F , to L , and setting one foot in C , with the other describe the arch R. Sixthly , Lay a rular , that it may only touch these two arches , S , and R , and by it draw a line as SR , cutting the line AC in N. Lastly , upon the point N , erect the perpendicular NM , then the distance AM , measured upon your Line of Chords , is the Azimuth from the South part of the Meridian , which in this example will be found to be 34 deg . MC the Azimuth from the North 146 deg . And MD , the Azimuth from the East or West , 56 deg . CHAP. XIX , The place of the Sun being given , to find the right ascension , Suppose the Sun be in the twentieth degree of Taurus , his right ascention is found as followeth . FIrst , as in the 12 demostrastion , draw the line BAF , for the Pole of the World , the ● upon the Center A draw the Circle BCDE , then from the Center A , raise the Perpendicular CAE , for the Equator , then place your greatest declination from C unto Q , and from E unto P , then daw the line QAP , which doth represent the Eclipticke line , then in regard the Sunne is in the twentieth degree of Taurus , which is forty degrees , from the head of Cancer , which forty degrees , place from Q unto L , and unto K , then draw the line KL , cuting the Eclipticke in I , then from the point I draw the line HI , parallel unto CAE , cuting the Pole of the World in O then set one foot of your Compasses in O , and extend the other unto G , with which distance draw the Semicircle HDG , then opening your Compasses unto the Radius of the Scale , and upon the Center O , likewise draw the Circle HNFG , then draw the line IM , parallel unto AOD , cutting the Semicircle HMDG , in M , then lay your Scale from the Center O , unto the point M , and draw the Line NM , cutting the Concentricke Circle in N , so shall the distance NF , be the right ascention , which is here found tobe two and fortie degrees , seven and twentieminutes . CHAP. XX. The elevation of the Pole , and declination of the Sunne given , to finde the difference of the ascensions . The Poles elevation is 51 degrees , 32 minutes , the declination of the Sun is 21. degrees . FIrst , as in the 13th . demonstration , draw the Line BAK , representing the Horizon , then upon the Center A , draw the Circle BCDEF , Then from K unto D , set the elevation of the Pole which is 51 degrees , and thirty two minutes : then from the point D , by the Center A , draw the Line DAF , representing the Pole of the World , then from B unto C , set the Complement of the Poles elevation which is thirty eight degrees , and 28 minutes : then from C by the center A , draw the line CAE , representing the Equinoctiall Line ; then from C unto G ▪ and likewise from E unto H , for the declination of the Sunne , which is 21 degrees , then from G unto H , draw the parallel of the Sunnes declination , cutting the Pole of the world in L , and he Horizon in I , then set one foote of your Compasses in the point L , and extend the other unto G , then with that distance of your Compasses draw the Semicircle GMNH , then opening your Compasses unto the Radius of your Scale , upon the same Center draw the Concentricke Circle , GXOH , then from I , where the declination of the Sunne doth cut the Horizon , draw the Line IN , parallell unto the Pole of the World AM , cutting the Circle GMH in N , then lay your Ruler from the point I unto the point N , and so draw the line NO , cutting the Concentricke Circle GXOH , in O , so shall the distance of O and X , be the difference of the ascentions , which is here found to bee eight and twentie degrees , and foure and fiftie minutes . CHAP. XXI . The right ascention of the Sun or of a Star being given , together with the difference of their ascention , to finde the oblique ascention or descention . The Sun is in the 4th . degree of Sagitarius , his right ascention is 242 degrees , or 16 hours 8 minutes , the difference of ascention is 1 houre 53 min. or 28 deg . 28 min. the oblique ascention or desce●tion is required . THe right ascention of any point of the Heavens being known , the difference of the ascention is either to bee added thereunto , or else to bee substracted from it , according as the Starre is situate in the Northern or Southerne Signes : As for example , if the Sunne be in any of these sixe Signes , Aries , Taurus , Gemini , Cancer , Leo , or Virgo , then the difference of the ascentions is to bee substracted from the right ascention , and the remainder is the oblique ascention . Suppose therefore the Sunne to be in the fourth degree of Gemini , where the right ascention is found to be foure houres , and 8 minutes , or 62 degrees , and the difference of ascention where the Pole is elevated 51 degrees , is found to be one houre 53 minutes , otherwise 28 degrees 50 minutes , which being taken from the right ascention , leaves two houres and 16 minutes , or 33 degrees and 42 minutes , which is the oblique ascention of the Sunne in the fourth degree of Gemini . But if the Sun be upon the South side of the Equinoctiall , either in Libra , Scorpio , Sagitarius Capricornus , Aquarius , or Pisces , then the difference of the ascentions is to bee added unto the right ascention , and the Product will be the oblique ascention . Suppose the fourth degree of Sagitarius is given , for which Sign and degree the oblique ascention of the Sun is desired , his right ascension being then found to be 242 degrees , or 16 hours 8. min. the difference of the ascensions is one hour , 53 minutes , or 28 degrees , 18 minutes : which being added unto the right ascension , makes 18 hours , and one minute ; or in degrees 270 degrees , and 18. minutes : which is the oblique ascention of the Sunne , when he is in the fourth degree of Sagitarius . And if you would finde the oblique descention , you must adde the difference of the ascentions unto the right ascention , when the Sunne is in these six Signes . Aries , Taurus , Gemini , Cancer , Leo , Virgo : and contrariwise , when the Su●n is in the other six Signes , you mnst substract the difference from the right ascention , and you shall have the oblike descention of the Sun or any Starre , whose right ascention and difference of ascentions is knowne . But it is to be understood , that this manner of operation , doth serve no longer than you are upon the North side of the Equinoctiall . For if the South Pole be elevated , the worke is contrary : for so long as the Sunne is in any of the Northerne Signes , the difference of the ascentions is to be added unto the right ascention , to find the oblique ascention . And contrariwise , substracted to finde the oblique descention . Likewise if the Sunne or Star be in the South●rn Signes , then is the difference of ascentions , substracted from the right ascention , to finde the oblique ascention , and added , to finde the oblique descention . The end of the Second Book . THE SEA-MANS GLASSE : The Third Book . Shewing how by the Plain-Scale , to delineate Houre-lines upon all kinde of Upright Plains , either Direct or Declining , in any Latitude . The figure of the plaine Scale . CHAP. I How to draw hour lines upon an Horizontal Plain , in any Latitude . VVith the Radius of your line of Chords , upon E as a Center , describe the Circle ABCD , and crosse it with he diameters AB , and CD . This done , out of the line of Chords take the complement of the Latitude of your place ( which we here suppose to be London , whose latitude is 51 deg . 30 m. and its complement 38. deg . 30 m. ) which set from B to G , from G to N , and from D to M ; then lay a ruler from A to G , and it will cut the line CD in H , and from A to N it will cut C D in O , and from A to M it will cut the same line in F. This done , upon O ( as a center ) place one foot of your compasses , and extend the other foot to F , and with this distance describe an arch of a circle , which ( if the rest of your worke be true ) will fall just in the points A and B , and so constitute the arch AFB , representing the Equinoctiall Circle , and so we shall hereafter call it . Having drawn the Equinoctiall AFB , divide the Semicircle ADB , into 12 equall parts in the points *** , &c. Then laying a ruler to the Center E , and every one of these marks *** &c. it will divide the Equinoctiall circle into 12 unequall parts in the points ●●●● &c. Again , Lay a ruler to H , and every of these unequall parts ●●●● , &c. it will cut the semicircle ADB in the points 7 , 8 , 9 , 10 , 11 , 12 , 1 , 2 , 3 , 4 , 5 and 6. Lastly , If you lay a ruler on the center E , and from thence draw right lines to the severall points 7 , 8 , 9 , 10 , &c. they shall be 12 of the true houre-lines belonging to an horizontall diall for the latitude of 51 degrees , 30 minutes . But for the houres before 6 in the morning , and after 6 at night , do thus ; draw the hour liues of 4 and 5 in the evening , quite through the center E , and they shall be the hours of 4 and 5 in the morning ; also , 7 and 8 in the morning drawn through the center , shall give the hours of 7 and 8 at night , as in the figure . CHAP : II. Concerning direct South Dials . A Direct South diall is no other then an horizontall diall , the makeing whereof is before described , the difference consisting only in the numbring of the houres , and in the placing of it , the one being to be fixed on a poste or the like , and the other to be fixed to a Wall which exactly beholds the South , I say here is no other difference : for   degrees   degrees An Horizontall Diall for the Latitude of 10 Will be a direct South Dial in the Latitude of 80 20 70 30 60 40 50 50 40 60 30 70 20 80 10 And the like in any other Latitude , as 15 , 16 , 33 , &c. CHAP. III. Of driect North dialls . A Direct North diall , is the same with a direct South diall ; for , i● you take a South diall and turn it upside down , causing the Sc●le or cock to point upwards , as the Cock of the South doth down wards ; and leaving out the hours neer the Meridian , in these Northern Latitudes ; as the hours of 9 , 10 , 11 , and 12 at night , and 1 , 2 and 3 in the morning , all which time the Sunne is under the Horizon . I say a South diall so disposed , and fixed against a direct North Wall , shall give you the true houre of the day . CHAP. IV. How to draw the houre lines on a direct East or West plain . This done , upon the point G , with the radius of your Chord , descirbe an occult arch of a Circle H I , and set thereon 15 degrees fr om H to I , then from G , through I , draw the line G K , cutting N Min K , On K , as a center , with the radius of your Chord , describe the quadrant K S T , which divide into 6 equall parts in the points ●●●● , through which points and K , draw the lines , K● , K● , &c. cutting the Equinoctiall EB in **** &c. Through these points *** , &c. draw right lines quiet through your plain perpendicular to the equinoctial , which will be parallel to your lines of VI , and XI , and will be the true hours of VII , VIII , IX , and X , then the like distances of VII and VIII , set above VI , on the other side , and drawn parallel thereto , shall be the true hours of IIII. and V. and thus have you all the hours of an East dial truly drawn , which is from Four in the morning , till Eleven at noon , and is the same with a West diall only naming the hours contrary : for , in the East diall 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , in the morning , are in the West diall 8 , 7 , 6 , 5 , 4 , 3 , 2 , 1 , h in the evening . The Stile of either of these dials , is a t in plate of brasse , made directly of the breadth of the distance between the hours of VI , and IX , and must be placed directly perpendicular upon the line of VI , and so is your diall finished . CHAP. V. Of upright declining Plains . BEfore we come to draw the houre lines upon a declining plain , two things are first to be discovered , viz. First . The height of the pole above the plain , which is the height of the Cock or Stile . Secondly , The deflexion , or distance of the substile from the Meridian or line of Twelve a Clock . 1. To finde the height of the Pole above a declining Plain . VVIth the tadius of your line of Chords , upon A , as a center , describe the Quadrant AB C , then your Latitude being 51 deg . 30 min. take it out of your line of Chords , and set it from B to F , and draw the line ED parallel to AB , cutting the line AC in D , then with the distance DE , on the center A , describe the Quadrant GHR . Then supposing your plain to decline 30 deg . set 30 deg . from B to F , in the Quadrant BEC , and draw the line FA cutting the Quadrant GHR in H , through which point H , draw the line SHN parallel to CA , and cutting the Quadrant BE C in N , so shall the arch CN be the height of the Pole above the plain , and in this example contains 32 deg . 37 min. 2. To finde the Deflexion , or the distance of the Substile from the Meridian . Out of this figure , take the distance HS , and set it in the line DE , from D to K ; through which point K , draw the line AKL , cutting the Quad ant BC in L ; so shall the arch CL be the distance of the Substile from the Meridian : and in thls Example will be found to be 21 degrees 42 minutes . CHAP. VI. How to draw the Houre-lines upon an upright Plain declining from the Meridian towards the East or West . VVE will here take for Example a South erect plain , declining Eastward 30 deg . Having ( by the Fifth Chapter of this Book ) found the Defl●xion of such a plain to be 21 deg . 42 min. And the height of ●he ●●ile ( by the same Chapter ) to be 32 deg . 37 min. we may proceed to draw the Diall in manner following . With the radius of your line of Chords , on the Center C , describe the Circle XNSW ; and in it , draw SN through the Center C , for the Meridian , or line of 12. Then the deflexion being found to be 21 deg . 42 min. set that from N to E , and draw the line ●C through the center to G ▪ This line representeth the Substilar line of your Diall , upon which line the Stile or Co●k must stand ▪ Also , out from your line of Chords take 32 deg . 37 min. the height of the S●ile , and set that distance from E to H , and draw the line CH for the Stile of your Diall ; so shall the Triangle ECH , be the true pattern for the Cock of your Diall . The Substilar line EG being 〈◊〉 ●●aw the line XW through the center C , and perpendicular to EG . This done , take the distance EH , ( which is equall to the Stiles height ) and set that distance from A to B , and from W to D. Likewise , take the distance from W to B , and set it from B to I. These three points I , B and D , being found in the circumference of the Circle XNSW , lay a ruler from X to I and it will cut the substilar line EC being extended in the point G , which is the center upon which the equinoctiall Circle must be described . Again , a ruler laid from X to B , will cut the substilar line in F , and a ruler laid from X to D , will cut the substilar in O. Now , if you set one foot of your Compasses in G , and extend the other to X or W , you may describe the Equinoctial circle XOW , which ( if you have not erred in your former worke ) will passe exactly through the point O in the substilar line before found . In the next place , if you lay a Ruler from F to N , it will cut the Equinoctiall circle in P , and a ruler laid from C to P , will cut the Diall circle in V. These things being performed , the next thing is to draw the hour lines , which will be easily effected if you 〈◊〉 the former directions . First , from the point V last found , begin to divide your houre circle into 24 equall parts ( or only one halfe of it into 12 parts ) which you may do by taking 15 deg . out of your line of Chords and set that distance on both sides of V at the marks ⚹ ⚹ ⚹ &c. so many times as the plain is capable of hours . This done , If you lay a ruler on the center C , and every of these points **** &c. you shall divide the equinoctiall Circle into 12 unequall parts in the points ●●●● &c. Now a ruler laid from F to every of these unequall points ●●●● , &c. will divide the houre circle into 12 other unequall parts marked with 4. 5. 6. 7. 8. ▪ 9. 10. 11. 12. 1. on the one side of V , and with 2. 3 ▪ ●n the other side of V. Lastly , a ruler laid from C to the severall points 4. 5. 6. 7. 8. 9. 10. 11. 12. 1. 2. 3. and lines drawn by the side thereof they shall be the true houre lines belonging to such a declining plain of 30 deg . in the Latitude of 51 deg . 30 min. But if you desire more hours then 12 , the equinoctiall may be divided into more unequall parts , being continued beyond X and W , and if you will , quite round the whole Circle , but that is needlesse without you would make 4 Dialls in the makeing of one as you may easily do . For , The hours that are on the West side of the Meridian of a South East diall , being drawn through the Center , will make a North West diall of the same declination . And the hours on the east side of the Meridian of a South West diall ; being drawn through the center , will produce a North East diall of the same declination . And Again , the reall houre lines of a South East diall being drawn on the other side of the paper , and the hours named by their Complements to 12 , that is , 10 for 2 , 9 for 3 , 8 for 4 , &c. will make a South West diall of the same declination . CHAP. VII . How to place any upright diall truly . ALL upright dialls , in what oblique latitude soever have the Meridian perpendicular to the horizon , wherefore to set your diall exact , hang a line with a plummet at the end thereof , and with a nail fixed in the line of 12 towards the top thereof , to hang the plummet upon , apply the diall to the place where it is to be fixed , so that the line and plummet may hang just down upon the line of 12 , neither inclining on one side or the other , the diall thus fixed if the declination were truly taken , and the dial rightly made , by the former directions , shall at all times ( the Sun shining upon it ) give you the true hour of the day . CHAP. VIII . How to insert the halve and Quarters of hours in all dialls . THe halves and quarters of hours are drawn in all plaines by the same rules , and the like reason , that the hours are inserted . Therefore take notice that if you would insert the halfe hours into any diall , you must divide your Equinoctiall Circle into 24 equall parts instead of 12 , and if you would insert the quarters , then you must divide it into 48 parts , and then proceed in all respect , as you did for the whole hours . CHAP. IX . How to finde the declinatioon of any upright Wall. THe declination of a plain is an arch of the horizon comprehended between the pole of the plains horizontall line , and the meridian of the place . To finde this declination , two observations must be made , the Sun shining , and both at one instant of time ( as neer as may be . ) The first is the horizontall distance of the Sun from the pole of the plain . The second is the Suns Altitude . First , to finde the horizontall distance . Apply the side of a Quadrant to your plain , holding it ( as neer as may be ) horizontall , that is to say , levell , Then holding up a thrid and plummet , which must hang at full liberty , so that the shadow of the thrid may passe directly through the center of the Quadrant , then diligently note ● through what degree of the Quadrant the shadow passed , and count those degrees from the side of your Quadrant which is perpendi●cular to the plain , for those degrees are the Horizontall distance . Secondly , At the same instant , take the Suns a●●itude , these two being heedfully taken , will help you to the plains declination by th rules following . By the 17 or 18 Chapters of the Second Book find the Suns Azimuth . Then observe whether the Sun be between the pole of the plains horizontall line and the North or South points , or not . If the Sun be between them , adde the Azimuth and horizontall distance together , and the sum of them is the declination of the plain . If the Sun be not between them , substract the lesser of them from the greater , and the difference shall be the declination of the plain . These rules sh●w you the quantity of your plains declination . But , CHAP. X. Shewing how to know whether your plain declin from the Meridian towards either the East or West . YOu must take notice in your observation , that if the Meridian point fall between the Azimuth and the pole of the plains horizontall line , then doth the plain decline to the Coast contrary to that wherein the Sun is , that is to say , if the Sun be to the Eastward of the Meridian , the plain declines to the Westward , But if the Meridian point be not between the forementioned distance and the pole of the plain , then doth the plain decline to the same Coast in which the Sun was at the time of observation . CHAP. XI . Concerning Polar Dials . A Polar diall is made in all respects as an East or West Diall is made , onely the line of 6 a clock in the East or West Diall , is 12 a clock in the Polar Diall , the houre of 7 is 1 , of 8 is 2 , of 9 is ● , of 10 is 4 , and of 11 is 5. Also the houre of 5 in the East or West Diall , is 11 in the Polar , of 4 is 10 , of 3 is 9 , of 2 8 , of ● is 7 , &c. The Cock of this Diall is a plate of Iron or Brasse made of the breadth between 12 and 3 a cloock , and set perpendicular upon the line of 12 , as in the East or West Diall it is upon the line of 6. In these Dialls the Equinoctiall line is to lie parallel to the Horizon , and not to be elevated according to the complement of the Latitude of the place , as in the East or West Diall it is . CHAP. XII . Concerning Equinoctiall Dialls . AN Equinoctiall Diall is of all other Dialls , the most easie to make , for if you describe a Circle , and divide it into 24 equall parts , and draw lines from the center through eve●● one of those equall parts , the lines so drawn shall be the true houre lines . For the Stile of these Dialls , it is no other but a streight Wyre of any length set perpendicular in the Center of the Circle , whose shadow shall give the true houre of the Day . CHAP. XIII . Of such Plains as decline very far from the East or West towards the Meridian as 75 , 80 , or 85 , deg ▪ above which plains the Pole hath small Elevation . SUch plains as decline above 60 degrees the houre lines will come very close together , so that if they be ▪ not extended very far from the center , there will be no sensible distance between hour and hour ▪ To remedie this inconvenience , there are severall wayes , I will instance only in one which is familiar and easie , and that is this . When 〈◊〉 have 〈…〉 your diall on a large sheet of paper , fix it on some large Table or smooth Floor of a Room , if the Diall you are to make be very large , as 5 , 6 , or 7 ▪ foot square , then by the side of a long Rular laid to the Center and every hour line , as also to the Stile and Substile , draw lines to the full extent of the Table or Flour , and you shall finde them to be of a competent largnesse . Then according to the bignesse of your plain , cut off the houres . Stile and Substile , leaving the center quite ou● , and yout work is finis●ed . CHAP : XIIII Concerning Declining Reclining and Inclining Dials . VVE should now shew the manner of drawing houre lines upon declining reclining and inclining plains , of which there are severall varieties , and many cautions , which in this place and at this time , would be too many to ennumerate : but if this which hath been already delivered concerning Upright decliners shall be kindly accepted , it shall animate me to do the like for all other plains whatsoever . FINIS . ADVERTISEMENT . NOte , that this Scale and all other Instruments for the Mathematicks , are made by Walter Hayes , at the Crosse dagers in Moore , Fields next doore to the Popes head Tavern , London .