the Amplitude from the east or west counting from 90. Example May the tenth it is 33. 37. CHAP. V. Having the Suns Declination or day of the moneth to finde the Azimuth at any Altitude required for that day FIrst finde the Suns Declination by the first Proposition of the fourth Chapter then take that out of the particular Scale of Altitudes or scale to 62 degrees then whatsoever the Altitude shall happen to be count the same on the degrees from 60 toward the end of the Rule according to the second maner of counting in the third Proposition of the third Chapter and thereunto lay the thred then the Compasses set to the Declination carry one point along the line of hours on the same side of the thread the Declination is that is to say if the day of the moneth or Declination be on the right side the Aequinoctial then carry the Compasses on the right side but if the Declination be on the South side that is toward the end counting from the tenth of March or Aries or Libra then carry the Compasses along the line of hours and Azimuths on the left side of the thâ—ead as all winâ—er time it will be and having set the Compasses to the least distance to the thread it shâ—ll stay at the Suns true Azimuth from the South required counting as the figures are numbred or from East or West counting from 90. Example 1. On the tenth of Iuly I desire to finde the Suns Azimuth at any Altitude first on that day I finde the Suns Declination to be 20. 45 which number count from the beginning of the particular Scale of Altitudes toward 62 and that distance take between your Compasses then are they set for all that day then supposing the Suns height to be ten degrees lay the thread on 10 counted from 60 toward the left end then carrying the Compasses on the right side of the thread because it is summer or north declination on the line of Azimuths it shall shew 110. 40 the Azimuth from the south required but if you count from 90 it is but 20. 40. from the east or west point northward according to the time of the day either morning or evening Example 2. Again on the 14. of November or the 6. of Ianuary when the Sun hath the same declination south-ward and the same Altitude to work this you must lay the Rule down on something then lay the thread on the Altitude counted from 60 toward the end as before and carrying the Compasses on the south-side of the Aequinoctial along the Azimuth-line till the other point do but just touch the thâ—ead and it shall stay at 36. 45 the Azimuth from south required if it be morning it wants of coming to south if it be after-noon it is past the south Example 3. But if the Sun be in the Aequinoctial and have no declination then it is but laying the thread to the Altitude and in the line of Azimuths the thread shall shew the true Azimuth required As for instance at 00 degrees of altitude the Azimuth is 90 at 10 degrees it is 77. 15 at 20 degrees 62. 45 at 30 degrees high 43. 15 at 35 degrees high 28. 10 at 38 degrees 28 ' high it is just south as by practice may plainly appear But if the Suns altitude be above 45 then the degrees will go beyond the end of the Rule To supply this defect do thus Substract 45 out of the number you would have and double the remainder then lay the Rule down with some piece of the same thickness in a streight line with the moveable leg then take the distance from the tangent of the remainder doubled counted from 60 to the end of the Rule in the line next the edge to the Center lay that distance in the same streight line from the tangent doubled and that shall be the tangent of the Angle above 45 whereunto you must lay the thread for the finding the Azimuth when the Sun is above 45 degrees high CHAP. VI. To finde the hour of the Night by the Moon FIrst by the help of an Almanack get the true time of the New Moon then compute her true place at that time which is always the place of the Sun very nigh at the hour and minute of conjunction then compute how many days old the Moon is then by the line of Numbers say If 29 dayes 13 hours or on the line 29. 540 require 860 degrees or 12 signs what shall â—ny less number of days and part of a day require The answer will be The Moons true place at that age Having â—ound her true place then take her alâ—itude and lay the thred on the Moons place found and work as you did for the Sun and note what hour you finde then consider if it be New Moon the hour you finde is theÌ„true hour likewise in the Full but if it be before or after you must substract by the Line of Numbers thus If 29 days 540 parts require 24 hours what shall any number of days and parts require The answer is What you must take away from the Moons hour found to make the true hour of the Night which was required But for more plainness sake I will reduce these Operations to so many Propositions before I come to an Example PROP. 1. To finde the Moons Age. First it is most readily and exactly done by an Ephemerides such a one as you finde in Mr. Lilly's Almanâ—ck or as to her Age onely in any book or Sheet-Almanack but you may do it indifferently by the Epact thus by the Rules of the 152 page in the Appendix to the Carpenters Rule Adde the Epact the moneth and the day of the moneâ—h together and the sum if under 30 is the Moons age but if above consider if the moneth have 30 or 31 days then substract 29 or 30 out and the remainder is the Moons age in days Example August 2. 1660. Epact 28. Month 6. day 2. added makes 36. Now August or sixt moneth hath 31 days therefore 30 being taken away 6 days remains for the moons age required PROP. 2. To finde the Moons place By the Ephemerides aforesaid in Mr. Lilly's Almanack you have it ser down every day in the year but to finde it by the Rule do thus Count six days back from August 2. viz. to Iuly 27. there lay the thread and in the line of the Suns place you have the Moons place required being then near alike then in regard the Moon goes faster than the Sun that is to say in 29 days 13 hours 12 signs or 360 degrees in 3 days 1 sign 6 degr 34 min. 20 sec. in one day o signs 12 degr 11 min. 27 sec. in one hour 30 min. 29 sec. or half a minute adde the signs and degrees and minutes the Moon hath gone in so many days and hours if you know them together and the Sun shall be the Moons true place being added to what she had on
degrees on the other side of the Rule and lay off 15 30 and 45 for every whole hour or every 3 degrees and 45 minutes for every quarter from D and E toward F and G for 7 8 9 and for 3 4 and 5 a clock hour points Lastly set C D or B E in the Tangent of 45 and lay the same points of 15 30 45 both wayes from B or 12 for 10 11 and 1 2 and to all those points draw lines for the true hour-lines required for laying down the Stiles height if you take the latitudes complement out of the Tangent-line as the Sector stood to prick the noon hours and set it on the line D F or E G from D or E downwards from D to H it will shew you where to draw C H for the Stile then to those lines set figures and plant the Dial Horizontal and the Stile perpendicular and right north and south and it shall shew when the sun shineth the true hour of the day Note well the figure following CHAP. XII To draw a Vertical Direct South or North Dyal FIrst draw a perpendicular line for 12 a clock then in that line at the upper end in the south plain and at the lower end in a north plain appoint a place for the center through which point cross it at right angles A Horizontall Diall A South Diall for 6 and 6 as you did in the Horizontal Plain as the lines A B and C D on each side 12 make two parallels as in the Horizontal then take A D the parallel and fit it in the sine of the latitudes complement and take out the sine of 90 and 90 and lay it in the parallels from D and C to E and F and draw the line E F then make D E and B E tangents of 45 and lay down the hours as you did in the horizontal and you shall have points whereby to draw the hour lines For the north you must turn the hours both ways for 4 5 8 and 7 in the morning and 4 5 7 and 8 at night the height of the stile must be the tangent of the complement of the of the latitude when the sector is set to lay off the hours from D as here it is laid down from C to G and draw the line A G for the stile For illustration sake note the figure CHAP. XII To draw an erect East or West Dial. FIrst by the fifth Proposition of the second Chapter draw a horizontal line as the line A B at the upper part of the plaine Then at one third part of the line A B from A the right end if it be an East plaine or from B the left end if it be a West Plain appoint the center C from which point C draw the Semicircle A E D and fit that radius in the sine of 30 degrees which in the Chords is 60 degrees then take out the sine of half the latitude and lay it from A to E and draw the line C E for six in the morning on the East or the contrary way for the West Then lay the sine of half the complement of the latitude from D to F and draw the line C F for the contingent or equinoctial line to which line you must draw another line parallel as far An East Diall A West diall assunder as the plaine will give leave then take the neerest distance from A to the six a clock line or more or less as you best fancy and fit it in the tangent of 45 degrees and prick down all the houres and quarters on both the equinoctial lines both ways from six and they shall be points whereby to draw the hoor lines by but for the two houres of 10 and 11 there is a lesser tangent beginning at 45 and proceeding to 75 which use thus fit the space from six to three in the little tangent of 45 and then and then lay of 60 in the little tangents from 6. to 10 and the tangent of 75 from 6 to 11 and the respective quarters also if you please so have you all the hourâ—s in the East or west Diall the distance from six to nine or from six to three in the West is the height of the stile in the East and West Diall and must stand in the six a clock line and parallel to the plaine CHAP. XIII To finde the declination of any Plain FOr the finding of the declination of a Plain the most usual and easie way is by a magnetical needle fitted according to Mr. Failes way in the index of a Declinatory or in a square box with the 90 degrees of a quadrant on the two sides or by a needle fitted on the index of a quadrant after all which ways you may have them at the Sign of the Sphere and Sun-Dial in the Minories made by Iohn Brown But the work may be very readily and exactly performed by the rule either by the Sun or needle in this manner following of which two ways that by the Sun is always the best and most exact and artificial and the other not to be used if I may advise but when the other failes by the Suns not shining or as a proof or confirmation of the other And first by the needle because the easiest For this purpose you must have a needle well touched with the Loadstone of about three or four inches long and fitted into a box somewhat broader then one of the legs of the sector with a lid to open and shut and on the inside of the lid may be drawn a South erect Dial and a wire to set the lid upright and a thread to be the Gnomon or stile to that Dial it will not be a miss also to extend the lines on the Horizontal part for the same thread is a stile for that also Also on the bottom let there be a rabbit or grove made to fit the leg of the rule or sector so as being pressed into it it may not fall off from the rule if your hand should shake or you cease to hold it there This being so fitted the uses follow in their order Put your box and needle on that leg of the rule that will be most fit for your purpose and also the north end of the needle toward the wall if it be a south wall and the contrary if a north as the playing of the needle will direct you better then the way how in a thousand words then open or close the Rule till the needle play right over the north and south-line in the bottom of the Box then the complement of the Angle that the Sector standeth at which may always be under 90 degrees is the declination of the Plain But if it happen to stand at any Angle above 90 then the quantity thereof above 90 is the declination of the wall To finde the quantity of the Angle the Sector stands at may be done two ways first by protraction by laying down the
distance in the degrees shall shew the Suns Azimuth required 6. But in winter you must do thus By the second Proposition of the ninth Chapter finde the Suns Amplitude for that day then take the altitude from the general Scale of altitudes and putting one point in colatitude lay the thread to the neerest distance then the neerest distance from the latitude must be added to the Suns Amplitude this distance so added must be set from the coaltitude and the thread laid to the highest distance and in the line of degrees it gives the Azimuth from south counting from the end of the rule or from the East or West counting from the head or 90 degrees Example At 15 degrees of declination and 10 altitude latitude 51. 32. the Azimuth is 49. 20. from the South or 40 degrees and 40 ' from East or West CHAP. X. To finde all the necessary quesita for any erect declining Sun-dial both particularly and general by the lines on the Dial side also by numbers sines and tangents artificial being Logarithms on a Rule 1. First a particular for the Substile COunt the plains declination on â—he Azimuth scale from 90 toward the end and thereunto lay the thread in the line of degrees it shews the distance of the substile from 12. Example At 10 degrees declination I find 7. 51. for the substile 2. For the height of the stile above the substile Take the Plaines Declination from 90 in the Azimuth line but counted from the South end between your compasses and measure it in the particular scale of altitudes and it shall give the height of the stile required Example At 30 declination is 32. 35. 3. For the inclination of Meridians Count the substile on the particuler scale of Altitudes and take that distance between your compasses measure this distance on the Azimuth line from 90 toward the end and counting that way it sheweth the inclination of Meridians required Example At 15 the substile the inclination of Meridians will be found to be 24. 36. 4. To finde the Angle of 6 from 12. Take the plaines declination from the particular scale of altitudes and lay it from 90 on the Azimuth scale and to the Compasses point lay the thread then on the line of degrees you have the complement of 6 from 12 counting from 60 toward the end Note this Rule as this line is drawn doth not give this Angle exactly neither will it be worth the while to delineate another line for this purpose But if it be required it may be done but I rather prefer this help the greatest error is about the space of 45 minutes of the first degree in the particular scale of altitudes so that if you conceive those 45 minutes to be divided as the particular scale of altitudes is like a natural sine and if your declination be 30 then take half the space of the 45 minutes less and that shall be the true distance to lay on the Azimuth line from 90 whereunto to lay the thread Example A plaine declining 30 degrees the angle will be found to be 32. 21. whose complement 57. 49. is the angle required 5. To perform the same generally by the general scale of altitudes and first for the stile Lay the thred to the complement of the latitude counted in the degrees from the head toward the end then the nightest distance from the complement of the plaines declination to the thread taken and measured on the general scale from the center shall be the stiles height required 6. To finde the inclination of Meridians Take the plaines declination from the general scale and fit it in the complement of the stiles elevation and lay the thread to the neerest distance and on the degrees it sheweth the inclination of Meridians required 7. For the substile Count in the inclination of Meridians on the degrees from 90 and thereto lay the thread then take the least distance from the latitudes complement to the thread set one foot of that distance in 90 and lay the thread to the neerest distance and in the degrees it shall shew the substile from 12 required 8. For the angle of 6 from 12. Take the side of the square or the measure of the parallel from 12 and fit it in the cosine of the latitude and lay the thread to the nighest distance then take out the nearest distance from the sine of the latitude to the thread then fit that over in the sine of 90 and to the nearest distance lay the thread then take the nearest distance from the sine of the plains declination to the thread and it shall reach on the parallel line or side of the square from the Horizon to 6 a clock line required Four Canons to work the same by the artificial sines tangents Inclination of Meridians As the Sine of the latitude To the Sine of 90 So the Tangent of the Declination To the Tangent of inclination of Meridians Stiles Elevation As the Sine of 90 To the Cosine of the Declination So the Cosine of the latitude To the Sine of the Stiles elevation Substile from 12. As the Sine of 90 To the Sine of the Declination So the Cotangent of Latitude To Tangent of the Substile from 12 For 6 and 12. As the Coâ—tangent of the Latitude To the Sine of 90 So is the sine of Declination To the Cotangent of 6 from 12. For the hours As the Sine of 90 To the Sine of the Stiles height So the Tangent of the hour from the proper Meridian To the Tangent of the hour from the Substile The way to work these Canons on the Sines and Tangents is generally thus As first for the inclination of Meridians set one point in the Sine of the latitude open the other to the Sine of 90 that extent applied the same way from the Tangent of the Plains declination will reach to the Tangent of the inclination of Meridians required CHAP. XI To draw a Horizontal Dyal to any latitude FIrst draw a streight line for 12 as the line A B then make a point in that line for a Center as at C then through the Center C raise a perpendicular to A B for the two six a clock hour-lines as the line D E then draw two occult lines parallel to A B as large as the Plain will give leave as D E and E G then fit C D in the Sine of the Latitude in the general Scale and lay the thread to the nighest distance then take the nearest distance from 90 to the thread and set it from D and E in the two occult lines to F and G and draw the line F and G parallel to the two sixes or make use of the Sines on the other side thus Fit A D or C D in the Sine of the latitude and take out the Sine of 90 and lay it as before from D and E then fit D F or E G in the Tangent of 45