OPA 
OOSTBOURG, in Geography, a town of France, in 
the department of the Scheldt, and chief place of a canton, 
in the diftri€& of L’Eclufe. The place contains 793, a 
the canton 4903 oo on a territory of 110 kilio- 
metres, in feven comm 
OOSTERADE, a own =” the duchy of Holftein; 
feven miles E.N.E. of Itz 
O IA, in en See Cun 
OSTERDYK 
STERHOUT, in Geography, a town “OF Brabant ; ; 
fix miles N.E. of Breda. 
OOS 
S.W. of Bois le Duc. 
ERZEELE, a town of France, in the depart ¢ 
of the Scheldt, and chief plac e of a canton, in the 
dittriG of Ghent. The place contains 2740, and the canton 
19,436 inhabitants, on a territory of 110 kiliometres, in 19 
commu 
nes. 
OOST. ROOSBECKE, a town of ee 
la 
in the de- 
e 
€ can- 
OOTAGA MIS, Upper, a town of America, on the 
river Ocifconfin, about 40 miles from the Miffifi 
at. 42° 42, ong. QI The Lower Ootagamis lies 
at the conflux of the two forementioned rivers. 
OOT town of Hindooftan, in 
ecu a 
Myfore ; nine miles S. f Wombinellore. 
OOTAMALLY, a town a Hindootltan, in Coimbetore ; 
30 miles S.S.E. of Coimbet 
OOTATORE, a town of Hindootay in the Carnatic ; 
2 miles N.W. of Tanjore. N. lat. 11° 24. E. long. 
8 58! 
“ OOTAWAS. See OTTAWAS 
WOODY, eile of pmncoonay in Coim- 
betore ; feven miles N. cf Dar 
oO MPALIA wn oo Hindooftan, in the 
country of Dindigul ; e ‘niles 'S. S.W. of Dindigul. 
IAMPALIAM, Valley of, a territory of Hindooftan, 
enclofed between the branches ofthe Gauts, on the weftern 
fide of the penin{ula, and extending 14 or 15 miles between 
the termination of the northern Gauts and the commence- 
ment of the fouthern ones from Paniany to Coimbetore, be- 
fore it opens finally into the low country on the Malabar 
aft. As it is = —— that pie which navigate this 
coaft during con, com 
ftronger Nr in hie nel eighbour irhood ar Paniany 
where, major Rennell, is of opinion, that this opening in - 
Gauts is a very fufficient caufe for fuch an effe€t; an 
the lower part of the Coimbetore country partakes of ie 
rainy or §.W. monfoon of the Malabar coalt, this may be 
referred to the fame caufe. 
ORL, a town of Japan, in the ifland of Niphon. 
N. lat. 34° 26’. E. long. 136° ‘, 
OOTS oT a sho of Hindooftan, i in Myfore; 30 
mi'es E. of Ret 
OP PACITY, in n° Philofa phy, a quality of bodies which 
renders them opaque; that is, impervious to the rays of 
light 
fts1 thie, 3 is at 
raight, or direétly before 
cr not pervious every way. 
But this doétrine is deficient: for” though it muft be 
allowed, that, to have a body tranfparent, its pores muit 
be ftraight, or rather cpen every way; yet how it fhould 
TERWYCK, a town of Brabant; feven miles g 
OPA 
happen, that ba only glafs and diamonds, but even wate, 
whofe parts a hed Pall tha ees have all their pores 
Open and aor ery way; an fame time, the 
fineft paper or the ree | gold cise fhould exclude the light, 
‘or want of fuch pores, is inconceivable. So that another 
Now all bodies have vaftly 
Qe. fo much rarer than 
vaculty as see ity. 
orty times as muc 
e bodies are opaque, does 
he c aufe, therefore, why 
he w 
of light in their paffage 
fractions and reflections, till, falling at leh on fome 
folid part, they become quite extinct, and are utterly ab- 
rbed. 
aa ee paper, lc &e. are opaque; while glafs, 
diam are pe For in ee? confines or joining 
of parts ake in deity, ach as thofe of glafs, water, dia- 
m mong t ves, ee arifes no refraction er 
celle Gliss, - reafon of t ce equal attraction every wa 
that, fuch of the rays of light as enter the firft furface, oe 
ftraight through the body, excepting fuch as are loft and ab- 
forbed, by firiking on folid paris; but in the bordering of 
parts s unequal j in deniity, fuch as thofe of wood and paper, 
the cont rary; t ae “fabftanc 8» by 
em a ng their poret, or ee en tee parts, ae be 
seueie very 0 Thus falts, or wet paper, or oculus 
mundi, by ete en by fcraping; glafs, by pulverifing, 
or flaw ing ; ; and water itfelf, by being beat into bubbles or 
froth ; are rendered opaque. 
Indeed, to render bodies opaque, and coloured, their in- 
terftices mutt not be lefs than of fome determinate fize; for 
nutely divided, as when 
a become perfe&tly tranfparent. 
RENC 
OPAH, or KinG-FIsH, in mech : Ry ieee of fith 
common on the coaft of Guinea; it is {mooth-fkinned, with- 
r 
See TRANSPA- 
a 3 
ifes below its neck, and 
alfo on each fide, behind the gills, a fins and a pair of fins 
a little before the vent under its beily ; from behind the vent 
runs one fin within a little cf the tails and the tail-fin is 
large 
