140

n Propoſitions in Diallinn- i 9So by having the Elevation G H, you may find D R the Declination.If an uprisht Plane(here) decline 20 fr. the Styles Elevation vill be

VI. 70 find the Defftectlon,& e.

Ount che Declination ftom B to 8: The Thred there laid gives E Kthe Deflexion. aI So by having F K the Deflexion, you may find BS the Planes De-dclination. f a 3If a Plane declining 20 gr. the Deflexion is 15 gr. 13.

VII. 20 lind the Dlference F Longitude,& c.

1. 7 1 1 Elevation from F to K: ES is the Difference of Lon-gitude. f 52. Count the Deflexion from G to H: C Riis tie Difference of Lon-gitude. iJ By the contrary Works, having the Difference of Longitude, youmay find the Elevation and Deflexion.A Plane declining 20 gr. hath 25 fr. difference of Longitude.

VIII. 75 nale an Horixontal Dial.

1. P Ount the Hour from E to S; che Thred laid at 8 gives E K. Thencount G H equal to EK; the Thred at K laid gives D R, theſpace of that Hour from 12. 52. Count the Hour from C to R, and by help of the Thred you ſhallhave GH. Then count E K equal to& H; the Thred laid at R, givesBos for the ſpace of that Hour from 12. a3. With a pair of Compaſſes take the Hour from C to Rand ſet ĩt fromB to S: BS is the Space or Angle of that Hour from 12.4. Take with your Compaſſes the Hour frem E to S, and ſet it from5 R: So the number D R ſhews how many Degrees that Hour muſt berom 1.2. 5By all theſe ways(here at London) the third Hour will be found about38 fr. from 12. The reſt will be in like manner found according to theirrue quantities,. 3

IX. 29