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<DATE>2008-07-06</DATE>
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<NAME>Mona Logarbo</NAME>
<RESP>MURP</RESP>
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<ITEM>Proofed and reviewed as part of batch B080613.pdcc.</ITEM>
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<IDG S="marc" R="UM" ID="B02644">
<STC T="W">D1160A</STC>
<BIBNO T="oclc">52212020</BIBNO>
<VID>175649</VID>
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<TEXT LANG="eng">
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<DIV1 TYPE="text">
<PB REF="1" MS="y"><!-- PDF PAGE 19 -->
<HEAD><HI>The De&s;cription of the</HI> Horological Ring-Dyall, <HI>which &s;heweth the</HI> Hour <HI>of the Day in any part of the World.</HI></HEAD>
<P>_IT is projected our of two great Circles of the <HI>Sphaere,</HI> An <HI>Axis,</HI> and a little <HI>Ring</HI> to hang it by. The greater Circle is the <HI>Meridian;</HI> one quadrant or quar|ter of it is divided into 90. degrees, to &s;et it to the <HI>Latitude</HI> of the place where|in you are: On the other &s;ide of this <HI>Meridian,</HI> is a quadrant of <HI>Altitude,</HI> to take the heighth of the <HI>Sun,</HI> whereby you may find the <HI>Latitude.</HI></P>
<P>The le&s;&s;er Circle, is the <HI>Aequinoctial,</HI> divided into 24. equal parts or <HI>hours.</HI> with their halfs and quarters; which are numbred but from <HI>III.</HI> in the morn|ing, to <HI>IX.</HI> at night: the re&s;t of the hours are left out, being &s;eldom or never u&s;ed.</P>
<P>The <HI>Diameter,</HI> or broad <HI>Plate,</HI> hath a &s;lit in the middle; and upon one &s;ide are the Months and Dayes of the year graduated to every fifty Day. On the other &s;ide is the <HI>Declination</HI> of the <HI>Sun,</HI> from the <HI>Aequinoctial</HI> to every fifth Day, which is to be u&s;ed with the Quadrant of <HI>Alti|tude,</HI> to find the <HI>Latitude</HI> of the place. The little <HI>Ring</HI> is made to &s;lide along the Quadrant, with a &s;mall <HI>tooth</HI> to &s;et it to the <HI>Latitude;</HI> which if you know not, you may find it in this manner.</P>
<DIV2 N="1" TYPE="example">
<HEAD>1. <HI>EXAMPLE.</HI></HEAD>
<P>Suppo&s;e the <HI>Latitude</HI> were unknown to you, and you would find it out your &s;elf, admit on the 11th of <HI>June,</HI> you mu&s;t by the former Rule find the <HI>Declination</HI> of the <HI>Sun</HI> for that day, which will be 23. degrees and a half, or 30. minutes <HI>Northwards;</HI> then take the height of the <HI>Sun</HI> at 12. a clock, which near about <HI>London,</HI> will be 62. degrees; &s;ub&s;tract the <HI>Declination</HI> 23. de|grees 30. minutes, out of 62. gr. and the remainder will be 38. degrees 30. minutes, the height of the <HI>Aequinoctial;</HI> take this 38. gr. 30. from 90. degrees, the remainder will be 51. deg. 30. min. the <HI>Latitude</HI> at <HI>London.</HI></P>
<P>Now if you ob&s;erve in the Winter half-year, <HI>viz.</HI> from the 13th of <HI>September,</HI> to the 10th of <HI>March,</HI> then you mu&s;t add your two &s;ums together; and the &s;um taken out of 90. gr. will be the <HI>Latitude,</HI> as before.</P>
</DIV2>
<DIV2 N="2" TYPE="example">
<HEAD>2. <HI>EXAMPLE.</HI></HEAD>
<P>Admit the 10th of <HI>December,</HI> the <HI>Suns Declination</HI> will be 23. gr. 30. <HI>Southward,</HI> the <HI>Meridian Altitude</HI> 15. gr. add the&s;e two &s;ums together, which make 38. gr. 30. min. the height of the <HI>Ae|quinoctial;</HI> which being &s;ub&s;tracted from 90. gr. leaves 51. gr. 30. min. as before.</P>
<DIV3 TYPE="part">
<HEAD>How to find the Hour of the Day.</HEAD>
<P>You mu&s;t &s;et the <HI>tooth</HI> to the height of the <HI>Pole</HI> or <HI>Latitude,</HI> and the <HI>Hole</HI> in the <HI>Plate</HI> you mu&s;t &s;lide to the day of the Month; then draw out the <HI>Aequinoctial,</HI> or le&s;&s;er Circle, and as near as you can, gue&s;s at the hour, and turn the <HI>hole</HI> to it; then hold the In&s;trument by the little Ring, and move it, till the <HI>Sun</HI> &s;hine through the <HI>Hole</HI> upon the middle line in the <HI>Aequinoctial,</HI> that is the <HI>Hour</HI> of the Day: And the <HI>Meridian,</HI> as it hangeth, &s;he weth the true <HI>South</HI> and <HI>North</HI> parts of the <HI>World.</HI></P>
</DIV3>
<DIV3 TYPE="part">
<HEAD><HI>How to find the</HI> Elevation <HI>of the</HI> Pole, <HI>or</HI> Latitude <HI>of the Place.</HI></HEAD>
<P>Fir&s;t &s;et the <HI>Hole</HI> in the moving piece, to the day of the Month; then turn the other &s;ide, and again&s;t the hole you &s;hall find the <HI>Suns Decliration</HI> for that day. The &s;ame day you mu&s;t take the <HI>Meridian Altitude</HI> of the <HI>Sun,</HI> which will be at twelve a clock every day, and may be perform|ed by this <HI>In&s;trument</HI> thus: Put a <HI>Pin</HI> into the <HI>Hole,</HI> which you &s;hall find in the <HI>Greate&s;t Circle;</HI> then move the <HI>tooth</HI> to the beginning of the degrees in the le&s;&s;er Quadrant, and turn the <HI>pin</HI> next to the <HI>Sun:</HI> and that degree which is cut by the <HI>&s;hadow</HI> of the <HI>pin,</HI> is the height of the <HI>Sun.</HI></P>
<P>If the time of your ob&s;ervation be from the 10th of <HI>March,</HI> to the 13th of <HI>September,</HI> you mu&s;t &s;ub&s;tract the <HI>Declination</HI> out of the <HI>Altitude,</HI> and the remainder is the height of the <HI>Aequi|noctial;</HI> which number being taken out of 93. degrees, &s;heweth the Latitude of the place.</P>
</DIV3>
</DIV2>
<DIV2 TYPE="advert for mathematical instruments">
<P>Note that this Dyal, or any other In&s;trument for the Mathematicks, are made by <HI>Walter Hayes,</HI> at the Cro&s;s-daggers in <HI>Moor-Fields,</HI> next door to the Popes-head Tavern, <HI>London.</HI></P>
</DIV2>
</DIV1>
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