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. XII.

Sailing from the South Longitude of 60 degrees, 51 minutes, and from Latitude 25 degrees, 24 min. 99 Leagues, upon a South-west course: the Lati∣tude and Longitude of the second place is deman∣ded.

IN the second Demonstration, draw the Quadrant A B C D E, as is formerly taught: then in regard you sail South-west, take foure points of the Compasse from your Scale, & place them from B, unto D, then by the point D, draw the line A D F, then place your ninety nine Leagues up∣on the Line A D F, from A, unto F, so shall E, be the place of your Ship. Then from F, draw the Line F C, parallell unto A E, cutting the line A B C, in C, so let the distance C A, be Leagues that you have run South, which is 70 Leagues. or 3 deg. 30 min. which being added to the latitude from whence you depar∣ted, makes sixty foure degrees and twenty one mi∣nutes for the Latitude of the second place: then take the distance C F, and apply it unto the Line of equall parts, and you shall finde it likewise seventy Leagues: then opening your Compasses unto the middle Lati∣tude 62 degrees, 36 minutes in the Line of Cordes, and apply it unto the first Line of Longitudes, you shall finde that nine leagues and 0 miles, and 38 se∣conds, doe alter a degree of longitude, then placing one foot of your Compasses in the second line of lon∣gitudes,

at 9 leagues and thirty eight seconds, and ex∣tend the other to one, then keeping the distance of the Compasses, set one foot in the seventy leagues of the same line, and the other foot will extend unto 7 degrees 37 min. which being substracted from the longitude from whence you departed, leaves seven∣teen degrees, and forty seven minutes for the Longi∣tude of the second place.