Speculum nauticum a looking glasse for sea-men : wherein they may behold a small instrument called the plain scale whereby all questions nautical and propositions astronomical are very easily and demonstratively wrought ... / by Iohn Aspley.

CHAP. XIV.

The Almicanter, or height of the Sun being given to finde the length of the contrary shadow.

BY the verse or contrary sha∣dow, is understood the length of any shadow, that is made by a Staffe or Gnomon stand∣ing against any perpendicular wall, in such a manner that it may lie parallell unto the Ho∣rizon, the length of the con∣trary shadow, doth increase as the Sunne riseth in height: whereas contrariwise

[illustration]

dem: 10:

the right shadow doth decrease in length, as the Sun doth increase in height: the way to find the verse shadow is as followeth. First, draw your Quadrant as is taught in the last Chapter wherin let A, B, be the length of the Gnomon, likewise from B, draw the line B E, paral∣lell unto A F, as before, then set your Almicanter from C, upon the Quadrant which is given to be 70 degrees, and it will extend from C, unto H, then from the point H, draw the line H A, cutting the line B E, in the point K, so shall K B, be the length of the contrary shadow, which here is found to be 34 degrees and 8 min. or twice so long as your Gnomon, and 10/12 and about ½ part of a twelfth more.