Hevel «rs’sr ConfiellktioHsÿ maâefsf0 k unformed. Stars.
Lynx _ - The Lynx - - ” - - --le) -
Leo minor’ The little Lyon . ’v'-’i-..* 'JS
Aft^ron^ab’^teharaî.'1- - T h e Greyhounds . - " *3""
•Cerberus- 1 . Cerberus - f i>v< 'Vt1!» V . ’ ■ -■ 4 '
V u l | | S la and &r*fèr' ^ 5 » The 7 0 x. .1111 Goofe É £ * P 1 - ! - 35l<,
föeutuhi Soh ieflsi p Sobiel 1 Shield 1 - - - - 7
;Xacfert£ -jy. -Th eX iza ifd . , - W ft.lO. :
,-Cameihpäf dalis . eft-' The ChamelUpard^n , J-; N ’ r.’ . ’ n . B IB
Monoçeros " " t :. s The Unicorn - "*■. J ‘f * jj, - ■ Kj-,e ’ 31-
y^e-xtans, f The Sextant - | ' - - - 11 41 :
TteiSoiiftellations as far as the triangle, with Coma Berenices, are northern • tliofe, after Pifccs,' in the ancient
:«onfteliatton, ^re fouthern Befides »thefletters which a!£ prefixed-tothe-ftars, many%| thpiirhave names, asfyrtuj,
regtfus i _ cirSurus11 ii&yry*
, Oh th'e proper Motion of the fixed' Stars. *
1 7 2 . "jpfej: Maskeiosnb,’ in.the firfl: volume of-his
Qbfçrvtilidns, rëipârk ,< that many, - i f not all the fixed
liars, haÿe JroaüjnptioBR ainongft thémfdves,-caHed;tKeir1
prefer mptipn^ a From comparing his own obfervations-
-with thgfe o f preceding aftfonomerp, Èefirfl-determined
the proper motionsjof^rrar, cajlorÿprocyoïi, potliix, rigu-
lus, arBurus, and a aqaiU jiafttfwaids -he determined.the
proper motions o f 35 gars in right afeenfion: ■ Thefe aie
grvfn ijça catalogué o f the-jigjfè aUenfionsSrf gfi.princi-
. p a l liars; which hediusidetermined tq an extrenre'degree
o f àçcuraey, and which arçqow generally ufed as'fundamental
ftars, in orcjer to determine thé right afeerifiods
o f.allïfhe'other heavenly Bbd f e v ÎM.- M avf-r has de-
teriflïoedTfeprôpéFrSitionôrjô'îlars.
173- i f the-fun be in motion as.wèll as the liars, it
will alter their apparent motion- In whatever-direSion
our Jyftem may be fuppofed to move, it.is eafy. to fee.
what effe£t it will have on the apparent mo tjo ifd ftne *
liars. D r. H erschel finds,, th a t .if a point Jbe af-
fumed about the ^ 0 o f right afeenfion, and. the fun to”
move from it, i t wifi account for the proper motions in
right afeenfion . o f the, feven- ahhye-mentibned ftars o f
D r. M askei.xne:; and if, inftead -of ftrppofing the fun
to move in the-equatarj it Ihould afeend to. à point.nc.ar
to R herculis, it. will .account for -the obferved ohange o f
declination o f Jiriue andj arBurus ; -hé means-, in-relpefi
to direBioh. g p g e x t obferves, that this motion;o f the
fun will account for m a n y / f the proper motions ob -
fèrved-by M a'xer. A J f o f rius mi-arciiwus, being.thé
largeft, are therefore pr.obably the neareft, arid-hence,
they ought to. have the greateft- apparent motion-; and
fo we find, they have. Cajlor is a double ftar; now,’
how extraordinary-mnft fuch a.-concurrence -appear,■
that two - fuch flars; fiieuM both haveTHe fame ptopèr
motion ; for they are found to continue at the fame dif-
taSce from each other. This feems to point out the 1
common caufë, the jjjbtion ö f jcfqt.Sjföem: From argn-
tP?.nts_,of this kind, D r. S e r scäe i, thinks that the
folar fyfiein is ill motion, in the direiStion above-men-
tlpMdiJI I
- • On. thel 'fjo;diacal' Ligh t.! .
; i 74' a pyramid of.fight-which,
foinel imes appears, fn the morning' .afujAipyehing,' before •
fun life, and/aftenfanifet. ' I t has. the fun for its balls,
and in- appearance .rufeuibles the aurora borealis. 'I t s
fides are not -ttraighfrjibutia littleUeüry di' relemblingva
lens fecn-cdgeoways. I t is .generally: Teeirin !0 6 £öh'ër
and March,- thé .twilight ' then-being Ihorteft. I t was '
obferved.by C as sini in ,1683, .a little before the vernal -
equinox,, im’lhe.'evenmgjiextending along the ecliptic
from the furC H e thinks tha t it had been obferved be-
fore ; for Mu.' J . "Cii i i.'iiE É^jiiila- book' 1 l :in
.6 6 1 , .gives aUaccóui t o f a,ph e*n imei on which-wlspró-
liably the fame. M . F at io de Du 11.l 1 e k/obferred it
foou .after C a s s in i . In 1.707, in A p r il 3, it was bli-
_ferred b.y Mr. D xkh m in EJex- I t appeared about a
■ quarter o f an hpm after fnn fet, and extended 150 ofioi-b
above the Fpriioii'. I t is'gehe'raHydfuppofed, that it is. .
matter which is thrown off from the fun, by its rota- j
tion about its; axis. .
1|||fl Th,e - true caufe the tidesfwas^ difeovered by
K e p ler. He fays that gravity is' a pjDwef'wJaipk is* öm-
t u a L b e t w - è e r i ; and that the earth and moon
wouldivmove*tdypard8 each other, arid -iKeet-at as'.'.
Jnucfo nearer, to the-ea>rth'éhan the moon, ii^the- moon is
lefs. than ^h©f.i:eRrth7 i f S | | | -motions in their orbits did^
nothinder thefii. Affd -h e. Further fhat the tidesT
'?rifé from the'gravity|oJ_the.waters:utowai-ds the moon.
S ir I» N ewton, 'From)\i8fjïjbeöïy o f Gravity, has ex-
plained th e ’general ,princijd'es upon which tli^pjbasno-
mena o f the tides depend, fro'm the unequal grayitation
©£.the digéirënt^garts-'of t h g ^ t h ithwards the fun and
möö’iï, 1 y?
| g g I f
1 1 176., I£rthe earth were entirely fluid, and at reft, by 4 tapt ’body more than another,,the figure muft neceflarily/
the mutual gravity o f its parts it muft form itfelf into a i be changed,
perfeot fphere, .But if orie^part-be attradeej. by ä dif-
M
m
‘ For let' A BDK be vf e f t ’ 'tó
■ perfedt- fphere, and let M b'p ^!diftanvt,bo’dy attra6tingv
i t ; then as the force ©f attradfion yaries inverfely"a& the
fquare o f’thêrdiftance, the ' nearer parts p f the earth .to"
M will be ^moie ^attraSied than ‘ 'fhqfe 'Further diftant!|
T h e parts at A will .therefore-he morenttradfed towards
-M than thofè^aÉl'he center 'C, and thofe at thé center
jnorèJhanJÜio^. a C Ö ;^ S h | ^ A 'jMw from C,*
an^’ C from 1) f and the effeft o f drawingsC'/.fro'm D is
tlÇ^fâme asNtóN©f>|rapip^^3- rappofith
direction. It- is .manifeft, therefore, that the jpar.ts at AM
all1 S ite
’others^ effeéls, the tides will" then be the lowefty and«
thefe are. called p H üifl'es.' | - Hence',’, there will he thtr:
hi^heff1 ti'd'es'at’néw and full moon, and low<sft when the r
moon is at fief firft and third'quartets.r- ,y
- 1 j*7 8. Thewater" will'1 e'ontinue 'to life for ’ sfo'me time :
after it has,paffedf the'mobn, as the effe£t o f the mçb'n î
will corÈtJnue thopgh in a fmalltr', d é g 'O ÿ .'^Ô ia t the ;
' water wifl 'ifpt'be the higheft at the time , when the;
moon■.ié ôrî the meridian/but it will fometimes happen,,
^o|ié,’dw.p£wi^i[,eé^BxifS}altpr,^èc9fmh^m fhe c^rcum-
ftances whicKffiha^^^^ÂHè motion-ofTlie^wateit.
' J 1:79. S ir I. N ewton ' has fliown th a t:tfifer‘‘e flçÆ o f f
tKemppm tó raife the'tides,. increafes as the cufih; o f the/
dlftande ä'efereäfes ;, hence, when4the moon is1 at its leaft.
diftâieeÿth^r elfe6t v^ll' hè.the greateft. The feine is*,
true in rëipè^ t'ó‘!the ftp.. " / '
‘ I i ' t ó .T h e tides ai e greateft when thc^attraFtxngjD’odv^,
fun.3of,; m tlje 111
pants o i f E A which'rare nearer 'to [ M than C is, will be
drawn from Q j, ^ d n ’ll the parts* o f are
further from M than, C is, will j bex left b y 6’, or may be
fuppoléd sto^fe-pawn- f r a ' ihxthe.'öp^o'fife'. dir.edt-ion
Thus, the wa-Çr|^illÇnfe "higher at A and Z), and being
drawnfïxóm<ÊCB^ hètN way^;:|ï^:mmft-- f t j l at\S';anl.
^ , andf 'fchê^eart'h will^ pjife; on T^e'elliptical form,
and'make fhigK ' tide at,’ ’m^and r,.piv 'oppoïite, fides, at
the fame time; and^tliere^will'be low ti'4'e a t pi &n<f ,jv at
the ^limeJ^t|m t V q ppppfit’N, poJ^sC whichlaremgc^V
fr.è'np>hë h ig h ji’d ^ the fun
oj: n^oMF ; but from its* • nearriefs <
to ^ f iè^ ë^ ^ ^™ lï^ ^ ^ f^ e rp h ^ .th a t of, iM ffin !
cpnfider ',ïnerefoF^th<^m^^^p. ;pH|(cma1|yi-ƒuling the
tiüeâj!^' A s tné'e^rtQ turrfs afioufitsfakispnoe everyday,
eyeiy^.par^pfithe earth wfll ®öm^^nc^|p?the mpçjîrima^
day^ an® fljq oppofite^o’the moon, 'am^therefore there
willm^^yqf mgh'-fides every day,* watef|wlli’'fall
to its loweft, twice in ,a> day^ O^ i y t ó r p ' rat^ly> nhe*.two •
tra'é^^^^^jn * about 2pi. tlie'i
jçob'n^S mMromi®|®^rhitF^ls 'tnat.'iptèml; ^roin^fie;
time+the^^^n -leaves the meridian till flie returns’ to
the n<qxttóii>.';vN
x^ 7 in;'.^^^£lion^(or|
in oppofitionr to each o*fheK,^fiçy w-ill 'Both tend to raife
the-waters at the fame places,"and therefore the -tides.'
wifi then ;||f;|he'
hut when the fum and moon ui’^'ÿoSffift'^each otlier,
the fun will tend tq lâ ëp r è^ which the tfiodn
tends- to^ raife, and therefore fhey ' oppoiihg? each
,For let, fo?' inftànçe, thp^mqqnjie'" in the. equator -
19 ;täfjß*
tide,’’and" C aiä tide ; then the ■
axis.pf the/ èart’K^ê^ng^htéfèpefgfM|cplar to. the plane'-
u d C À ^ a fpeaâtor at ^ o r^ ^ ^ |eJ e. it f is high tide,
.^îll^ÈpFh.è' e a rth!^ rotation',' be'-'carried^^td f-’ or. Z ? ,.
where it i s S g 'tide^'/a^id therefore .tfi^iflerence between
of,
thé water at high and low iidei Now fupçdfeiZÔ^