The mariners magazine, or, Sturmy's mathematical and practical arts containing the description and use of the scale of scales, it being a mathematical ruler, that resolves most mathematical conclusions, and likewise the making and use of the crostaff, quadrant, and the quadrat, nocturnals, and other most useful instruments for all artists and navigators : the art of navigation, resolved geometrically, instrumentally, and by calculation, and by that late excellent invention of logarithms, in the three principal kinds of sailing : with new tables of the longitude and latitude of the most eminent places ... : together with a discourse of the practick part of navigation ..., a new way of surveying land ..., the art of gauging all sorts of vessels ..., the art of dialling by a gnomical scale ... : whereunto is annexed, an abridgment of the penalties and forfeitures, by acts of parliaments appointed, relating to the customs and navigation : also a compendium of fortification, both geometrically and instrumentally / by Capt. Samuel Sturmy.

[ V] To finde what Sign the Moon is in, by which is gathered, what the Moon differeth from the Sun.

MUltiply the Age of the Moon by 4. divide the Augment or Sum by 10, the Quotient sheweth the Sign the Moon differeth from the Sun; the Remain multiplied by 4, giveth the Degrees to be added. As for Example,—The Moon 22 days old, I demand what she differeth from the Sun? 〈 math 〉〈 math 〉 Multiply 22 by 4, and the Product is 88. That divide by 10, and in the Quotient is 8, and 8 remaineth upon the Division: That multi∣plied by 4, is 32; from which take 30, the number of Degrees in a Sign, and add the 8 Signs in the Quotient, it makes 9 Signs. The odd 2, multiplied by 4, make 8 Degrees; to which add the Sun's Motion from his entrance into the Sign ♎ which was the 14 day, to the 21, make 7 days or Degrees to be added, to the 8 Degrees make 9 Signs 15; which counted after this manner, from ♎, saying, ♏ 1, ♐ 2, ♑ 3, ♒ 4, ♓ 5, ♈ 6, ♉ 7, ♊ 8, ♋ 9 Sign, and the odd 15 Degrees is 15 Degrees of Cancer. So the Question is answered, That the Moon is 9 Signs 15 Degrees from the Sun at 22 days old; which note, She differeth but 4 Degrees from her true Motion by the Tables, which is near enough for the Mariner to answer any Man.