241

0 B S

0 B E

>nf(.|.j 0 r ’ t ' le oak from the central parts of Europe is alsoTlie ] ’ es Pecially in compactness and resistance of cleavage.(fi'OQj „ °ak of England, when cut down at a proper age,at otiee^ sevent y years,) is the best timber known, for8 pli I)t • su PP ort > n g a weight, resisting a strain, and nota cannon-shot; hence its value in ship-

' v at,

Bred

is the appellation given to those fertile spots,Mattered ^ s P r ' n S s a "d covered with verdure, which areHiey a a kout the great sandy deserts of Africa. In Arabic <.„. Cal ¥ wadys. The Arabic and the Greek name

be

Qi tn

the

_ 0 ..„, _. , B _ west of

sey ° r , Khargeh ; the little oasis, or Wall el Bahryeh,JS»n smi tiler ones, which are noticed under Egypt .

S ° ma y be considered as a great oasis of the Sahara .IICc otim '"I 0 bas described Fezzan ; Browne has given anS| lnll er 0 t *' e oasis of El Khargeh, and Cailliaud of the

°J'a. ~

^ appear to be depressions in the table-land of-rally a n S°ing from the Nile westward, the traveller gru-Pkti ae »ds till he arrives at the summit of an elevatedcontinues nearly level, or with slight undula-I ? totvar i Lonsi< era ble distance, and rises higher on advan-1 U ' 11 , and 8 tbe sout b. The oases are valleys sunk in thisSn ‘ a when you descend to one of them you find thev nll u . P a Ce or nloin

0tl| e di 8 t lj ®^Pb surrounded by steep hills of limestone att, 98 ' 8 >s sa^ 6 bom cultivated land. The low plain of the1° bl(! surf * 8tone or clay, and from this last the water risesp''d i 3 bin.]' 1 ' 26 ’. an d fertilizes the country; and as the table-^’P f , * er ' n tke latitude of Thebes than in that of Lower

ey p 0r plain of the oasis similar to a portion of the

We

^''Veved^ 87 rea, % imagine that the water of the oases'fined bv *i ° m some elevated point to the south, and being

is

gv^ ._ r ___ o

tbe ked of clay, rises to the surface wherever thep ^EHeTf- eiStratum ' s removed.

g at uid v , ’ (^ ro, n the Latin , obeliscas,) a quadrangular8 j p^y Blender and high; raised as an ornament ino*®! and l p Pl ac e, or to show some stone of enormous^‘ics. re< l u ently charged with inscriptions and hiero-> Eoi^i' ,

“r 0a f derives the word from the Greek, ®

«> B }:/Pind!e, or even a kind of long javelin 1 J ^*M»«an S cut their obelisks in torn^ 111 Ike Phoenician language, the word obelisk sy

The

Se n . ^Syptian

.... - - pnests called their obelisks the suns fin-

USe they - •

the

llOnV b ® C!

tj e on tne y sei ‘ved as styles, or gnomons, to mark the>t^ e *s wt 6 sround. The Arabs call them Pharaoh ’s'ra A ' 8 JjJ' !nce the Italians call them aguglia. See Cleoto 1 * e difr IH ' KS -

8o, he, o 0 e n re . nce between obelisks and pyramids, according

fit

ifi

tli n ^ 0l 'ttlp < l nS * Sts * n this, that the latter have large bases, and

. u »h

ner

Ca

i ,.o-* vj a ,.j. ei T sni; dl ones, compared witli their heiglitiri' 8 ' 58 aro - Un nia kes the difference to consist in this, that1 Pvr, . to biof

ttn,] '" 8 are t k

'K ^atnid ° ° e a P' ece > or consist of a single stone ;

. Ptonrf sev eral.

a y ' a all f 11 ? 113 the height and thickness are nearly the"es 5 f ’ S0l net‘ ebsb s ; that is, their height is nine, or nine and

Ulu 5 ^ di a uiiJCO Llicil lUlLMlcaa j anv-i mol*-

is never less than half, nor greatera H(] *’ 8 kinj U f tll8) that at bottom.

t'ty’ '7® are t i , monum c n t appears to have been very ancient;v fen - ®'Prin(C ' ’ Was first made use of to tran... u, Pal precepts of philosophy

In after-times they

ten times their thickness ; and their thick-

transmit to poste-■- Precepts of philosophy which were engra-‘ 111 hieroglyphic characters. ^ * ' '

3 Q

were used to immortalize the actions of heroes, and the me-mory of persons beloved.

The first obelisk we know of was that raised by Rameses ,king of Egypt , in the time of the Trojan war. It was 40cubits high, and, according to Herodotus , employed 20,000men in building. Pliius, another king of Egypt , raised oneof 45 cubits ; and Ptolemy Philadelphus another, of 88 cubits,in memory of Arsinoe. See Porphyry.

Augustus erected an obelisk at Rome , in the Campus Mar-tius, which served to marl# the hours on an horizontal dial,drawn on the pavement.

F. Kircher reckons up fourteen obelisks, celebrated abovethe rest, viz., that of Alexandria, that of the Barberins, thoseof Constantinople , of the Mons Esquilinus, of the CampusFlaminius, of Florence, of Heliopolis , of Ludovisio, of St.Mahut, of the Medici, of the Vatican , of Mount Ctelius, andthat of Pamphylia .

One of the uses of obelisks among the ancients was, tofind the meridian altitudes of the sun at different times ofthe year. Hence they served instead of very large gnomons.One of the obelisks now standing at Rome , that of St. John’sLateran, is in height 108 English feet, without the pedestal ;and the other obelisk, brought to Rome by Augustus , buriedunder the Campus Martius, wants but little of the sameheight. Pliny gives a description of this gnomon, lib. xxxvi.sect. 15. From him it appears, that there was laid down,from the foot of the obelisk northward, a level pavement ofstone, equal in breadth to the breadth of the obelisk itself,and equal in length to its shadow at noon, upon the shortestday; that is to say, that its length was to the height of theobelisk, almost as 22 to 10, and that under this pavement,there were properly let in parallel rulers of brass, whosedistance from the point, directly under the apex of the obelisk,were respectively equal to the length of the shadow thereofat noon, on the several days of the year, as the same lengthsdecreased from the shortest day to the longest, and againincreased from the longest day to the shortest. Vide Phil.Trans. No. 482, art. 5, vol. xliv. p. 365 ; where we also findsome remarks by Mr. Folkes on Hardouin ’s Amendment of aPassage in Pliny’s Natural History, lib . ii. sect. 74, about thelength of the shadows of gnomons in different latitudes.

OBLIQUE LINE. When one straight line stands uponanother, and makes unequal angles therewith, the angles aresaid to be oblique, the one being greater than a right-angle,and the other less. Hence a line is only oblique, as it relatesto another line : without this distinction, the word would bedestitute of meaning.

Oblique Angle, one that is greater or less than a rightangle.

Oblique-angled Triangle, one that has no right angle.

Oblique Arches, are those which conduct high roadsacross a river, canal, open drain, &c.,in an oblique direction.—Oblique arches are otherwise called skew bridges. SeeBridge Arch.

OBLONG (from the Latin oblongus) a rectangle of unequaldimensions.

OBSERVATORY, or Observatorium , a place destinedfor observing the heavenly bodies ; or a building usually inform of a tower, raised on some eminence, and covered witha terrace for making astronomical observations. The morecelebrated observatories are, 1. The Greenwich Observatory,or Royal Observatory of England, was built in 1676, bvorder of Charles II. at the solicitation of Sir Jonas Moore and Sir Christopher Wren , and furnished with the mostaccurate instruments by the same, particularly a noble sextantof seven feet radius, with telescopic sights. The province ofobserving was first committed to Flamsteed, a man who