firft day o f the n ext' year % a Monday, agamft .which A i
{lands, G willfiandagainft th ? fii-ft:Srifi.day, aridtfiere-
-fo're- againft. every "Sunday in tha t'jear. ïiFor^Mïl fame
reafon, the firft day of the - npxt year îs Tuefdày, and-
feeing marked w i A , F g U ft and .âgâifift ‘every Sunday
in the yeal^ and. fo on. * Therefore'.the Sunday
letter's will come- on in an inverted ©îder,' A , G , F , E,_
D> C , B., >in the fucceffive«years'; ~h@n©||thefc are called
dominicél letters/ • This would-be thê^cafe; if tlîWèwer#
-$ n p‘i' Igrijp- -■ y ear " ok years, -of- '366- days ; .when - this hap-?
yensywe additional day:thns taken is-marked5 with the
fame letter,- which riece-ffarily throws-the Sunday letter
ôriëléteër back for the red o f the year. Hence, in,leap
yéAM&ëte fere two dominical letters, the firft takes placé-
before -February' 29,' the fécond after. A s therefore t li| '
regular- change o f the } Sunday letter which would fee '
completed,- in 7 years, is .thus interrupted every four
years, the- Whole change will be completed in>ÿX '4>^hr
-yeafs.^But -this will be fometimes -interrupted, be-
caufedevery threecentenary years out- o f ‘ four, are not
leap years, a T he year o f our Sa^iour^s 'bfrth' was the
9th o f this 'cyëlé^f.theréfore; t-o find‘the ypar o f this
pycle, add nine to^the .given year, and'divide the fum b y
28-, and the quotient« {hows the number o f cycles1 elapf-
e:d -fmee his- birth) -and the remainder is the cycle for
ihë-'yêâr ; i f nothing remains,"the; cycle is 28.
*£33. T he cycle of the moon,t fometimes'-called the Me-
ionic cycle from the inventor Metón, is j®period ó f 19
years, in- which times,- the cö^unélïbns, oppôfitïotis, àlfd
all dthér'afpeéls ó£the moón-, teturn óri thefàmèdays'of
the month as they did c i9 yean! before, but about \\
hour'^ fpqner. T h e anéients formed’ this cycle thus-,:
Taking any year for the cycle, they obférved all the
days bn'wMçh the new moon happened; through thè'j
t year, and againft each fuch day'they placed the number
H| in the fécondé- year o f the-cycle they did the
fame, placing the number 2 ; and proceeded in like-
mariner through the cycle o f 19'years. This being done
for one cycle, the famé numbers w ere .fitted to the -ca’J
léndar to (how ' the new moons in every future cycle}
aridfon aécourit ó f their great ufe, they were written in
góldy. and thénee c a l l golden numbers. Bnt the difference
o f ■ about i f hour in 19 yearâ iricregfes tó a whole
day fn about-"31 2 years, fo that;this cycle'ca'n only hold
fo r that time s 'fo r "as the rièw arid full moons'aiiMcfs '
pate a day in that time, the golden numbers 'óught tö
ÿ é placed’ one 'day earlier in the calendar for the next
312 v years'. I t was thought proper, however, to make
t'lis correction at the end o f whole centuries ; accordingly
they put the new moon forward one day at the' end
©revery 300 years, for feveri times foccefiEivëly, which
makes 2100, yéars î and to account for the odd i"£\
years, they'deferred putting the moon forward to the
erid o f 400 years, making the period o f $ X 3 12F—
iyob 'years., T he golden number were properly placed
b y the eponcii -of Nïcé, A . T ): 335 ; the anticipation,
which has been neglected ever fincé, is now become al-
móft'5 days, and therefore all the goldetmumbers might
now to be placed 5 days higher in the calendar for the
7 •
oidjltle, than they were a t fche-abdve-tnéntroned^öuncil5.'.
Qr 6 days lower for theiffewJlile. <- B u t becaufe the lunar
cycle o f r 9 yearè 'fometimes tncludes ^ and fometimes c .
lèap' yeèrs, 'it ris impdfitble'to-Have a ;cörre6t table^of i l l •
the numbers,' u>nlefs"i4 -he extended, to 4 X 19 * or‘7.6 years.1
A n d fn this fcafé it; méft ;be; idapted to thei qld^JHkyht-t
ckufe in every^ cehtetia’iy "year not«, divifihle b y 4?’ tlie^ré-
gular cotfrfe oft^the^leap year i s l i r i t e - r r u p t e d -
Jlile:- T he -ycarolfokir Saviour’s birth vya's- the firft year ■
of&he lunar c irc lk f' hen'rife,^to?firidVfc any time; t’he^oyclè a
S fori* the year; add bW-tbtfiie given y dar) r is t , and I
-divide 'thefum by 19, and-the quotient ié thfeinumber o f 1*
cydléè'firi'èei^e the Remainder ijo'
thëy>Gygle‘;for t h é or tlfe golden number, ■ arid 1
’ if' nothing remain, 1 9 , the evele/ .
' 234.-'The'^-7^? is -in d%^afetfie |
gfofik^lóFthè year/ u L e t a new moon happen on- J anu -;
ié nothing. • .Novv - as ii 2 /
lunations are completed in 354 days, it is plain that the ;
epa£t, or moon’ s ag"e,{ Would be ’ 11 at the beginning-* o f
the- fecond year ; 22 at tfie^ beginning o f the third^year;;.
an d ‘33. at the-begirininig&plf^t'he fourth : but aö oné luna-:
■ tion -is never' more than days, the cpa£t mull always *
be lefs than ,30; thereforefobtraiding 3x*>-fr0di: thete^«
remains 3 for the epa6l for the fourth yeaj-. A u d byprO-^
^céëdfng thösFör * 1 ears, thfe^a^s ^wilh ftaöd ^hhs"; »efe
i r , 235:3? i'7if>28] ^4,«. 15,^
' 2t>,“ 57, 18, o j ; in ' the''nine^éerith' yëarf ^Ire -difference .
amounts to 29 days,-and th e r e fo r em o n thw h ic h is fo b -.
traded mu ft' confift^nly o f 2 9 days, in-©rd,er"t'ha't the-ep'ad^
may begin- agalri', las it mu ft, the new« foqonïfatüriglöny
January ill. Th§f#fepads fbeing placed againft' tMe^-
day s 4 o f thé months ini;the calendar, lonlW-foch^fhemeW^
moons fall in eaefoyèarf anfi^ver'-t-he fa-me'-lphtp0fe: as the •
g ’old^n numbers^ Bu'tTt is'liab’foto b’ë interrupted every Jiö'«
years| for the fam^ teaforis -the mbbri'havfo^ the^'ahtici^
pat Id a5 Whöle^day^ aöd^héréfofb %h^t'h'e firft year,, o f the
cycle, the moon would • b'e on'e-day" old' on the firft of,
January ; therefore thl' epkd: 5^ould-be increafed, ’by« 1,
and-^ftand thus:n j \ i\ 23, 4, &c. p-Blip this arrange-^
merit would- bè‘ iritètöüpted1 by the bmimon o ^ h e leap
year, every-three centuries «out o f '4 ;«'fë^thefe years^
being a day M s th?an b y the accétliJt; the new
moons wbuld 'happen a day later, arid jfieMforilmakêi'
epact!r lefs. - -The-radonVage here fujjporqdV«the
mean new1 irio'Ori/ that is, the ne,w moon-that would hap-«
pen, i f the moon‘iïtóvfedl,umform'Iy with its meari v-elock*
t y ; blit as the m^oB?s|^©jtion^is variable-, the true new-
moon happens at a different' tim^iand may fometimes
differ a' d ay,. thslt^ 1S5' bnê” mriy_fri|Hin ©rieday, and the
other in the rule there-*
fore by which-We find !Éaftery »that feftival isï riöt^ always
found to' agree with the*' %rrie deduced^:/fom' themew1
moon, as put down in our Vlmanacsj’ fo r théfe^thê tirrie
Of the trite néw: iriooil is put d ow n ; whereas, in r thé;
rule for finding Eafter, the mean neW rftooft« istrifod. In*
the correction o f theBritilh calendarj we ufe the “golden1
numbers,' ommitting the epaCts; and havé placed the
golden numbers,. not againft the days o f the new moon,
hut
i t
but o f full moori) an<l asfa| flss^aspj
. fb£^@j_af-montha, Mar^b..an®&pKu,Sm,-foiidcr .to find
' 2$y. T h e indillion\i3^f^^cl% o f i^ 'y e aH , arid was
' ufed by the .Romans- for indicating th© times o f certain
payments,*-.made by the,fu|3jeQ;% tp. was
eftablifiied b y N ^ i .N a y r i j e,in the.year
confined; fo i^ j^ r s y p ^ n l^ f i a ^ o ^ f ib ^ i t was
ipftituted,, are, pot
g'iyerilye^^, * lapi^div^de- th^^gi^^der, fey what remains
is the indidion for the given year ; and if nothing
remain,■ the indidlion is 15. V|
^ 3 .3 ^ J h e Cycl^o^^^e^GdM.sd the fyoqyjian Period,
i^fche pro.pq^^of,tneA/<«'?and chiefs o f 28
years= 5 3 2 yham* ' H the ntew:^©^aMiSn^a)i^
Upon, this circle, as 'in arV 33^3,, Eqjlmlda^
ways
follpws March 21. ^ B ut on account o f that aptieipatioiic
before the alteration-ofi the ftile^the EccUfradical Eajl&r
kagpened, within this century, a week different from the:
true- Eajler. But this ds^'n'ow.ijemiedied'in. the
Prayer-Book, b y making the tafele, which ufed to find
ju jler fo r ever,, o f np' longer pfe than the
237. T he Eafter is March^^.arid.thehtejl i i
April 25 ; fo^ ifo/zkr Sunday is alvvays tke firijj^mday
mqon,; which happen^. Up©n prv n^i|tf^afoer,
March 2 ift.t Wifhin thefe _tlimits there are/35 days,,
and the number belonging to each is called the
q f diti^ign. ; B
.. d f i , M a p s . . t
.23 B. A map is- l-ltc repteftrltsMon cfr^fiOTP^Sface o f
tb s earth upon a plane j abd tbdfe are1 ‘ejflierr general
or particular. A general ojap, is a map o f iho w*h^e
earth, ^nd^this is 'reprefented iif two -circles- tpuchitig-
ea§h otlier, reprefentmg two heipifptterfcs-.of tjie dirSi,
tbe'ih'ouftdaries o f which are meridians. A partitular'
map; isa-map-of dhly apart tef the (pifae'e o f'tlK eattb^as'
ofrpn'to f the quarters o f the world, or o f any particular
country;. T he laying clawjf- bT.tHefc tnhps is, called projection,
o f whkih there are* fo-end1. Icmtls.', s
2'39, In map , three principal things an required!
1 ft. T o lhow the latitude and-lqngiiude- o f places ; and
this', is. dofteby dvaw-iug a certain number of'meridiansj -
and parallels, o f latitude. 2d. T he fecond requifite i s , '
to ethibit, as nearly as you e^n,' the ihape pf- all flip -
countries, for it cannot be done-aeCTrStely by any pro-
jeitiori, on acequnt o f its being made on a plane, when
the .earth is- globular. 3d. The third' is, to ihow
the bearings pf'lplaees from each other> and tlleir distances;
the former ean be done in one projeftidn, tu t
the lattercauhot;,;
- t ip . ■ Tho-projection o f maps is made accorch'tg to the 7
rules-of perfpe£tive. - 7 f t he eyeS^^irppofed to view the
earth from an-infiiiiti diffiance, the appearance' reprefent-.
‘ ed upon a plane is called an 0rthrrgraphrf Ipfojrdti-STi.
this cafe, the parts ato'nt’the middle are very well repre-
fented, but the ' . , i afe very much contradled..
‘ i So n . ir
But the method generally made ufe. o f b y geographers
for maps,, is the ƒ creograpAir, where the eye is fuppofed
the earth, and looking at the op-
is alfo a projedtion called
globular, in which meridians, equidiftant upon the fur-
face o f the earth, are reprefented by equidiftant circles in
the map. There is alfo another projection, ufed b y navigators,
called ftferatfor’s, in which, both the meridians
‘ and parallels o f latitude are réprèfetfted by ftraight lines.*
Thefe are cafted^/oi c& r if, wherein are exhibited fome
part .of'tBmféa^tvith the (bores that bonhö' i t t h e inlands
are generally omitted, as being o f no ufe to: the
failpr; but the parts near the (hore are carefully laid
down, with marks.Cgnifyilig roaks, fands, or flats, and
figures etepfdffrngiki^Mlitdingl, or depths o f the water.
The accurate method o f .conftrufling.all kinds o f maps,
may be feenin the TrèntileiqfAftronomy before referredto.
‘ 241. When we are to delineate a map o f a jpfiaUpart
o f the earth, i f 'it b.e near the equator the meridians and;
patafldsjqf latitude ^ a y 'b « feprfefenteci by éqtffdiftant
lines. I f at'fbWs'^fl^rice ft-oih thé '-éqüafopi-tËe
mètw^is< rfiiflï then1 tfc tfiade? to converge _a ifttl|, and
t h e . ' r f d f e w .H h t 'p d u retedê (^öm'Ihë’ ?qviatdrJ«"
;244. When a map M made of'a Defy fmall dj/biS, as b f
a^county*, bh whatever part o f the parth it «1, the me-
, i^»sMd‘,|iataW|’b^faArffeïinay'be' répteumted by,
é^A^öntslaTallelfljp^s.'j*
- t f^ . ’ rAffrle which cuts all the meridians, at the fame
called a,rhumlf iiue ; as long therefore as a (hip
fails. upaflftheTattie .rhunrb, it fails upon the fame (point
tile proje&ioii o f the difcpdians*
is v y iiiifeles, jhfen ÖreiVhjimblliiè' is a*curve; but when
the meridians- are reprefented b y ftraight and parallel
lints, the rhdmb becomes a ftraight line, it being the
property o f a ftraight line tet cut parallel ftraight lines in
'tfo f im e a b ljW iƒ --
t 244. fianCQ great ufe o f Tt/erraror’ siChartjyduch is
cohftrufted .upon this principle. Upon the earth’ s fu r-.
fate; the degrees o f latitude are all equal, but the
degrees o f longitude decreafe: as you approach the poles,-
as we have explained in art. 10.. Now in this projection,
the 'Meridians being equidiftairt '.fnaight Ifuc’!5> the de-
grees ó f longitude muftbe every, where equal; in order,
therefore to preferve the proper proportion between the
degrees 'o f longitude and latitude, the ‘degrees o f lati-
tude are increafed in a proper proportion ; the degrees
o f latitude therefore increafe as yyp gó, Crorh the CQua-
tor to the pole. Now in failing from one place' to another,
théi'!(horteft Why iVtp'faif upon a great circle,
but that is a thing which is imprafficable, there being '
nothing to direft you in fuch a courfe Navigators
therefore,' when they have to go from one place A to
‘ ahöthérT^.flïld %(oh ^yhat rhumb they -muft fail, that is,
upon whaf point o f thé cómpafs they mufttgo, lo as to
coraefto' B, and by; their (leering compafs they can! tell
iwlten they fail on thé fame point. Now on Mercator's,
'pi.oiccaoTi',' 1 f '.ybuVd'raay a ftraight line from A to B , it
gives you the rhumb required ; for in thefe maps,' there
is ;a point alfuined, and from it there- are drawn 32
- k. ' ; ftraight '