Navigation. 
other throughout her course by one point laying down a traverse course on paper, 
of tlie compass, being governed throughout Having drawn t!ie meridian and parallel of 
her passage by that line only. This is dif. latitude (or east and west line) in a circle 
ferent from what is called traverse sailing, representing the horizon of the place, mark 
winch arises from adverse winds, or some- in the circumference the place of the wind 
times from currents, and obliges a vessel to that is, the point from which it blows ; draw 
change her course occasionally; especially your rhumb passing through the place bound 
where the vicinity of land renders it neces- to, and lay thereon the distance of that 
sary to steer at times differently; lest the place from the centre; on each side of the 
current, wliigh generally changes from one wind lay off in the circumference those 
side or direction to another, should set her points, or degrees, that shew how near the 
against the shore. When the wind is dia- wind the vessel can lie, and draw their 
metrically, or obliquely against a ship’s rhumbs. Now the first course will be one 
direct course, she must make traverses, i. e. of these rhumbs, according to the tack the 
zig zags, which is effected by laying her 
head as close to the wind as may allow her 
sails to be filled when close hauled ; (see 
Plate XI. Miscel. fig. 12.) in which A is 
the place of departure, B the point of desti- 
nation, from which the wind blows direct, 
and A 6, he, c B, &c. tbe course the ship 
must steer to arrive at B. Square rigged 
ships generally can lay within six points of 
the wind ; but sloops, &c. commonly lay up 
within four points and a half. When work- 
ing in this manner it is called “ beating,” or 
“ plying to windward:” when the wand 
blows straight upon the side of the vessel, 
it is said to be “ on the beam ;” when be- 
tween her side and stern, it is called “ a 
quartering wind,” or “on her quarter;” 
when direct astern, or near it, she is said to 
be “ before the wind,” or to “ sail large.” 
When the wind from being fair becomes 
suddenly foul, it is said to “ take her 
aback.” 
In traverse sailing the vessel’s head is 
usually turned up “ into the wind” when 
she is “ put about.’’ This is called “ tack- 
ing ;” but if, instead of “ throwing her up” 
in that manner, she is allowed to go round 
from the wind until it comes or is met by 
her on the other side, it is called “ wearing.” 
When she has the wind on her starboard, 
or right bow, she is said to “ have her star- 
board tacks aboard,” and vice vei’sa when 
the larboard, or left, bow is to the wind. 
To know how close a ship will lay to the 
wind, observe the course she goes on each 
tack, say north on one, and south-west on 
the other; divide in the middle, and her 
course will appear to be west-north-west. 
But allowance must be made for lee way, 
which is the loss made by the impression 
made on the vessel as she is working to 
windward ; when the wind presses her from 
the direct line of her course, and occasions 
her to “ drift to leeward.” See Leeway. 
The following is the established rule for 
VOL. IV. 
ship first sails upon; when she goes on the 
other tack, it will be at such an angle as 
may correspond with her ability to lay near 
the wind ; but, in general, for square-rigged 
vessels the angle should be twelve points, 
(i. e. six for the distance on each tack, as 
shewn in fig. 12.) But where the wind is 
not directly adverse, it would be improper 
to make the tacks towards both rhumbs of 
equal duration or length. Therefore that 
tack should be longest which lays nearest 
the intended course ; the other (i. e. “ the 
board”) should be short, so that the vessel 
should not go too far from the intention, 
but adhere as much as may be practicable 
to the rhumb of her course, as shewn in 
fig. 13, in which the arrow shews the wind’s 
locality at three points east of the destina- 
tion B. 
To resolve a traverse, is to reduce and 
bring several courses into one ; the courses 
are known by the compass, the distance by 
the log: while the dead-reckoning they 
produce is corrected by daily observation 
of the sun and other planets whenever op- 
portunity offers. 
In constructing figures relating to a ship’s 
course, let the top of the paper always re- 
present the north: your meridian is des- 
cribed perpendicular thereto, and your 
chart may either be in squares, for degrees, 
or live or ten degrees, or it may be divided 
according to the projected tables now in 
common use (see Longitude), and which 
is by far tbe best, as it shews the real dis- 
tances and bearings, according to the actual 
positions of places, as proved by observa- 
tion. In that table the letters D. L. imply 
the degree of latitude, measured from the 
equator, either northwards or southwards ■ 
in the columns of miles corresponding there- 
to, you will see how many miles, of sixty to 
a degree, called geographical miles, are 
contained in each degree of longitude under 
such latitudes. Thus, if I would know how 
Rr 
