441 / 868
A
v
1
G
~9°
tioo began
to be u-enerly;
a-nd in
the
y~ar l G 7~,
it
was
obferved tO be
2° 30'
'Y ;
alfo io the year t 683' it w>s
4° 30' \V; and (inee that time the variation Itill conti·
nU~5
at London
lO
incrc;¡fe wcflerly ; bm how far
il
wiH
go th" w.y. time aod obfery.tioos will probabJy b: the
.Ql1 l y
means
(O
dt[co\·cr .
Again,
al
París, in {be year
1640,
the v:ariation \Vas
!jQ
00'
E;
2nd in
the
year 1666, there was no variarían;
but io the ye...
168 1.
it was
2
0
30'
W. aod
IHII
eOOli·
Dues to go
wcClerly.
lo
filort,
from obCer-vations made in differcnt
pan s
of
the world, ir a-ppears,
thal
in different places (he varia·
tion dd'Fas both
as
to
jls qu an'tity
and denominatioo,
it
being eafl 'in one place, and wt:ll in another; the true
eaufe .od theory of whieh, for waot of a fuffieient numo
b<r
gf obfervatioo,. has oot as yet been fully explaioed.
Sc'a 9.
7 he M ET llo D ofk"ping a
JOURHAL
o/po;
ond
hIY1.U lo corre{] il,
by
/Ralillg
pr4p,r JZllfl'UJQllcrJ/or
Ihe
leeway, variation,
Oc_
t .
LE
[ · WA
y,is
lhe
ang-le-that the ....hom bline
1
\tpon
which
lhe
Ihip
(ndeavours
ea
f.úl,m:\kes with lhe rhomb Ole
~eally
faiJs upoo . T hi, is oceafiooed by the force of .he
"·ind or Curge of
the
fea,
",hen
fue lies ro the windward,
or is clofe hauled. whieh eQuf<s her to fall off and glide
lide·.ways f,om the point of the compafs !he capes al.
Thus let NESW (No.
3<.)
reFrefeot the eompafs; .aod
fuppofe a Ihip at C capes at. or
eode'-vour~
to fail upoo.
the rbomb
Ca;
but by the for<e of the wind, aod furge
of the fea. Ihe i, obliged to fall
aIf.
and make her way
g.ood upoo
the '~hoOlb
Ch;
then the aogle
IlCb
is the
Ice·
..vay ; aod if tJ.¡at angle be equal to ooe poioi. the !hip
is
raid to make one point lee way; and ir equal to two
points. the Ihip is fa id 'o make ewo pointS lee.way.
ce.
2 .
Thc
quaotity of this
angle
is very uncertain, becaufe
fome !hips. with the fame quantity of
f~il
• .aod with the
fame gale,
will
makc more lee-wa'Y than others;
ie
de–
pending mueh upoo the mould aod uim of the Ihip. aod
the quaotity of wat<r that Ihe draw,. The eommon al·
lowanecs ·that are generally made [or the l<e.way. are as
[ollow.
t.
I f a Ihip be clofe hauJed. has a\J her fails fer. the
water fmooth, and
a
modera te
gaJe or wind, !he is then
fuppofed tO make linJe or no lee.way.
2.
If it blow fa fre!h as to eaule the fmall f.ils be hand·
-cd,
it
is uCual to
allow
one point.
3 11
ir blow fa hard that the 'op fai l. mu!l be clofe
reefe, then the common allowance is two points {or lee–
way.
4 .
If one topofail .mull be handed. theo ,he Ihip is fup–
paCed to make betwecn two and three points lee v. ay.
5.
VI'heo both tOpofail. mu!l be h.aodtd. then tbe al·
lowance is about {our poiots {or lec-way.
6 .
lf
blows fo hard• .as to oeeafion the fore.eoerfe to
be haoded, the a\Jowance is bctween
5-1-
and 6 poinlS.
7.
W heo bo,h maio aod fore·eourfes mull be handed.
,hen
6
!"1T
6
r
points are eommooly a\Jowed for lee-way,
8. Whco the mizen i, handed. and the Ihip is u yiog a
hull. Ihe i, theoeommooly a\lowed about
7
poiolS (or lee–
way.
-3
Thoullh thefe rules are fueh as are ¡¡enerally made
A
T
1
-o
N.
ufe
0(.
yet finee ehe lee.w,y depeods rnocbt\;pon rbe nron14
ami trim of (he
fhip,
it is
evident that theycannot exaüly
fervo to overy Chip; and therefore the be!1 way is td Ilod
It
by obfcrv>tioo: Thu,. let ,he Ihip', wake be let by a eom·
pafs in ,he poop, and the oppofit< rum& is the "ue eourfe
made good by the Ihip; theo the dlfferenee betweco thil
and the courre given by the compafs in tb.: bitcaclc, is
the lee ..wa.y required . . If ,be lbip- be with," fight of
J.od; theo the Jee· \Vay may b.
exa~lly
fouod by ob–
.fer\'ing
a
POiOl
on
the:
land
which continues
tO
bear
lhe
fame way, and
~he
.dil\-anee between ·,he poiot of the
eompafs it lies
UPQO
and ·,he .poiot tbe !hip e"pes .,
will be Ihe lee. way. Thus fuppofe a lhip at
e,
i. J)"iag
up
NWb,
towards
A;
bu, ioltead of keepiog that eourle,
Ihe is earried 00 the NNE Jioe CH. and eonfequeody the
pOlnt
B
contioues to
be;u
the fame
w:¿y
from
the
(h,p:
Here it is evideot. tha! the an¡¡le ACD. or .he dilt"nee
betw,ea the
NbW
lioe that .he lhip capes at. aod the
NNE line thar the Ihip rea\ly fails upoo. will be tlt.
I':e.way.
4- H a.ing the .eourfe !leered. aod the lee.way, giveo;
we may from thenee fiod the true eourfe by the followin¡:
method.
viz .
L e' your faee be tu roed direétly to the
windward; aod .if tbe Ihip baye her larboard tacks
01\
board,
COUDt
the
lee·way
(rom the courre fieered towards
,he right haod; but if the !larboard taeb be
00
board.
then eouO! it from the eourfe !leered ,owards the Jeft
hand. Thus.
fuppof~
the wiod at oorth, and the Ihip lie.
up within
6
poinlS of the wiod, \Vith her larboard laek.
on board,
making
one point Jee": way; here it is
plain,
tha' the eourfe ,leered is ENE, aod the true eourfe
EbN; alfo fuppofe the wiod i, at NNW, and the !hip
lies
up within 6{- poinls of
the
wind
w~th
her llarboarJ
tack on ·
bo.ud, making
11-
poine Jee-wi\Y, ir ¡s evident
that the true courCe,
in
this careo
¡s WS\V.
) . We have Ihewed , io the hll feétioo, how
'o
60d
t'he
val ¡ation
o{
lhe
COmpleS;
and .from
what
has beeo
fa id there, we have this general rule (or fiodiog the Ihip's
true eourfe, haviog .the eourfe Reered aod the v\,iatioo
given,
viz.
Let your face be turned rawards the pointof
the eompafs upoo w"hieh the Ihip i, !leered ; and i( Ihe
variarion be eaflerly, cou'!t lhe quanlity ofü {rom lhe
eourfe !leered toward, the righ. haod"; but if we!lerly,
towards ,he leCt hand; and the eourfe thu, found is
the true eourfe !leered . Thus. fuppofe the eourfe !leered
is
NbE.
aod the v","iatÍoo one poiot eaHerly; tbea the
true eourfe !leered will be NNE: Alfo fuppofe the eourfe
!lecred is
NEbE,
and .he variarioo ooe poiot IYe!lerly;
then in this eafe. the uue eourte will be NE ¡ aod fa of
o1hers.
He~ce.
by knowiog the lee·way vanation. aod
eou~fe
llecred, we may from tbc:nce fiDd the f'hip··s true courre;
bUI ir rhere be a curreoe under foor. then that mur! be
tried. and proper allowaDces made {or it, as has been
f'hown in the Cetlion concerning
CUrr~nIJ,
{rom thence
[O
fiod the uue eourfe.
6.
After making 'all the proper allo'..,aoces (or fiod ing
the f'hip's true courfe, and mak.ing as jufi: an eflimate of
l"e
diílance as \Ve can; yet by reafon of the many acci–
d, nts that attend a Ihip io a day"s runoing. fueh as diffc–
reo, rates of failing belweeo the times o( heaving the lag,
the