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.

CHAP. V. A Table for the Division of the Artificial Rhomb, or Points, Halfs, and Quarters on the Travis-Scale.

Points.	Nor. South.	Deg. Min.	Sine parts	Tang Rhomb.	Tang. qu.p
	N. b. E. 1	2 48	688		689
	S. b. E. 2	5 37	990		992
	S. b. W. 3	8 26	1166	1	1177
1	N. b. W. 4	11 15	1290	7	1298
	N. N. E.	14 3	1385		1398
	S. S. E.	16 52	1462		1481
	S. S. W.	19 41	1527	2	1553
2	N. N. W.	22 30	1582	6	1617
	N. E. b. N.	25 18	1630		1673
	S. E. b. S.	28 7	1673		1727
	S. W. b. S	30 56	1710	3	1777
3	N. W. b. N.	33 45	1744	5	1824
	N. E.	36 33	1774		1870
	S. E.	39 22	1802		1914
	N. W.	42 11	1827	4	1957
4	S. W.	45 00	1849	4	2000
	N. E. b. E.	47 48	1869
	S. E. b. E.	50 37	1890
	S. W. b. W.	53 26	1904
5	N. W. b. W.	56 15	1919
	E. N. E.	59 03	1933
	E. S. E.	61 52	1945
	W. S. W.	64 41	1956
6	W. N. W	67 30	1965
	E. b. N.	70 18	1973
	E. b. S.	73 7	1989
	W. b. S.	75 56	1986
7	W. b. N.	78 45	1991
	East & West.	81 33	1995
	84 22	1997
	87 11	1999
	90 00	2000

THe Use of this Tabe is easily understood: The first Co∣lumn is the Number of Points in one quarter of the Compass, and the second their Names in the whole; The third the Degrees answering to each quarter of a Point in the Quadrant; The fourth the Sines and Equal Parts answering thereunto; The fifth the Tangent-Rhombs; The sixth the Tangent-parts answering to each Quarter and Point to 45 Degrees ½, which is sufficient.

The Description of the Travis-Scale.

The making of this Scale is all one in a man∣ner as you made the former; only the Line of Sines is there but once made, and here the Parts answering each Quarter are twice put down, or in two Lines marked with N. S. which stands for to shew the Line to be Northing, Southing; and E. W. signifies Easting and Westing. The first is the Sine, the second is the Complement that any Point or Quar∣ter maketh an Angle with the Meridian. The Line marked with T. is the Tangent-Rhomb and Quar∣ters, and the first Line is a Line of Numbers, which you have been already shewn to make.

[illustration] geometrical diagram

The Traverse Scale.

One Example I will give the Learner, notwith∣standing it is so easie; for some there are that will not understand, though they see it often done; yet (to my knowledge) are Mates to good Ships.

EXAMPLE.

Suppose you was to set the first and seventh Rhomb or Artificial Point on the Scale, which is 11 Degrees 15 Minutes, the Equal Parts answering thereunto is 1290; therefore take 129 of your Scale of Equal Parts, and lay it from the beginning upwards, and you have by that distance the first and seventh Rhomb of your Scale.

In like manner do for any other of the Points and Quarters by these Numbers, until you have fi∣nished the Scale; and when you have done, you have an Instrument the most easie, ready, and necessary that I know of, for the working of Travises, and correcting your dead Reckoning, which shall be shewn in the Part of Sailing by the Plain Chard, in the Fourth Book. On the back side of this Scale you may set a Line of Chords and Equal Parts, and Points, for the ready protraction of Angles.