PIL

297

PIL

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Pr° Ve(1 ’ j^ 1 ' Wocks, of however

large dimensions. It wasexperiment, that if a screw with a broad spiralJ°taiy " w “ fixed upon a spindle, and forcibly propelled byi Ce Wo n° n to a certa * n depth into the ground, an enormousfi'ut tl le u a fie required to abstract it by direct tension, andl fie ^ 0Vfer employed must be sufficient to drag up a massdie su,.p ,n a frustum of a cone reversed, the base being?9u»l t 0 ,, ace ef the ground, and the section of the apex beingOtaao le dimeter of the screw. The extent of the resist-

tli,

Ve rti

dftass

soil

. ^fst of course depend upon the natural tenacity of'"eat f even in this reasoning it must be evident that a0r ° lce "'as calculated upon, but as practically thatth e hi never occurred, the angle of tension and the curveof 3 Was f y - cabl « again gave the moorings greater power.

•lie.se n ° Un .d to be correct in practice, and the applicationsfttiade °°! In g® became very extensive. An arrangementf ® r tli e Su w iti> the port of Newcastle-on-Tyne , by which,th'* 'i'yne ^ ^2,500, the right of fixing the moorings in

at ’ * n tl'p^r £' ven ; and Mr. Brookes, the engineer, showed

4

""a?,

"“ge ‘otlowing year, whilst in the neighbouring porto ^Pi000 ; ^ done to the shipping to the extent of nearlytti ln ? to ’ a j u 'T was sustained in the Tyne, entirely°®ting s _ tlle sound holding of Mitchell's screw-pile

N. 5^% occurred to Mr. Mitchell, that the sameho be pro 9lstance to downward pressure might be used,p^tisea, b ea g° se d to apply it for the foundations of light-^ r Poses j(. '° ns > and other structures, which for maritimegfit be desirable to place upon sand and mud(' ldac e a le hitherto it had been considered impracticableS', il stl 'Uctif fi eitnanen t edifices. In the year 1838, a planat re of this nature for a lighthouse on the Maplinjj* af >on 0 p atouth of the Thames, was laid before the cor-5 •' dain es yl? Trinity House, supported by the opinion ofj n v alker, their engineer. The 9 iron piles,t>i'o° 1 ' l * in glv A ‘. ame ter, with screws 4 feet in diameter, werehef a 6r pi'e Cau , r . IVen 22 feet deep into the mud, and, with*** any en 'fi 0 ’ the y were allowed to stand for two years,^alt' lbse Qup 1 i 6 Was Placed upon them. The lighthouse1'li 6 ^ er ten v!« constructed, and, as was testified by Mr.

.^an (q? a ? s after, had stood perfectly until that time,an,} beino- j . P*l' n g ‘ n this instance was octagonal,j” ficiven in each of the angles of the octagon,a a 'a th e ; r n . t,e centre, making in all 9 piles, which were' P aces in 9 consecutive days, being screwed to

of

of Stl,~

SL ^ . in the bank. The piles were madet,le foot. Cas t-i r ° n ’ 5 '

- 11-011

inches in diameter, and 26 feet long,

screw, 4 feet in diameter, screwed to

1,1 tlnh ot fier jm, .tf p, la >'b 0Ul . * ta °use was erected to point out the entrancel'h e a f‘ t ain 0 Fleetwood on Wyre ; and under the advice* b °Ut S ^ 0t fix4r ham ’ K-N-, the screw-piles were adopted.8c, 'e\v l ' v ° mi] ° n Was the point of a bank of loose sandbio l). 8 3 f ee ? S • t^'oru the shore. Screw-iron piles, with

> and . ln fi'ameter, were forced about 16 feet intoC, 1, "-ere "P0 n them timbers • ' - 1

CS w! fixe fi> to carry the

"’er e them timber-supports, 48 feet in vertical

xed, to carry the house and lantern. This3 corn pie

prove the value of that description of

-^ ) ” '

o-u ,, — "pun them timber

%*****-' , Va ... a ud the few

..Mrs ni' ua completed in six raon 1 ’

I'Ue, has required

>^"?h of P iVm S was u.Me? r tlm h^ad

> lt Ve much on the subject under

m 4 * that U 53 n0t neC6S8a 7

among builders, a word sometimes used for aav. '■

Ifftl ^ \V\\[, . w .

bavV 8tan ding behind a column to bear upL i t _ n g a round base and capital, as a pillar lias.4 G

the

PILLAR (from the Italian piliere, or French pillier) akind of irregular column, round and insulate ; but deviatingfrom the proportions of a just column.

Pillars are always either too massive or too slender forregular architecture. In effect, pillars are not restrained toany rules ; their parts and proportions are arbitrary. Such,for instance, are the pillars which support Gothic vaults, andother buildings, &c.

A square pillar is a massive work, called also pier, orpiedroit, serving to support arches, &c.

A butting-pillar is a hutment* or body of masonry, raisedto prop, or sustain, the thrust of a vault, arch, or otherwork.

It seems not impossible for stone to be cast into the shapeof pillars. We find mention made in the PhilosophicalTransactions (No. 481, p. 328, in note,) of two pillars ofstone at Fontevraud, in France , each about 60 feet high, allof one solid piece, which are said to have been run. Pillarsof stone were anciently erected as sepulchral monuments,near the highways; and also in memory of some victory.We find traces of this custom in Cornwall and Wales , wherethese pillars are often found, and called meinigwir, a stonefor play, perhaps in memory of funeral games ; and sometimesllech, that is, tabula saxea.

Pompey ’s pillar is a famous monument of antiquity, con-structed of red granite, and situated on a rock, about a milewithout the walls of Alexandria, in Egypt . By the mensu-ration of Edward Wortley Montagu , Esq., the capital of thepillar, which is Corinthian, with palm-leaves, and notindented, is 9 feet 7 inches high ; the shaft 66 feet l£ inch ;the base 5 feet 9f inches ; the pedestal 10 feet 5-g- inches ;the height from the ground 92 feet : though Dr. Pococke,by the shadow, determined the whole height to be 114 feet;and its diameter 9 feet and an inch. It is perfectly wellpolished, and only a little shivered on the eastern side.Nothing can equal the majesty of this monument: seen froma distance, it overtops the town, and serves as a signal forvessels. Approaching it near, it produces, says Savary, anastonishment mixed with awe. One can never be tired withadmiring the beauty of the capital, the length of the shaft,nor the extraordinary simplicity of the pedestal. This pro-digious mass stands, as on a pivot, on a reversed obelisk ; andwas erected, as many have supposed, either by Pompey , or tohis honour. But as no mention is made of it by Strabo ,Diodorus Siculus, or any other ancient writers, Mr. Montagu concludes that it was not known before the time of Vespasian ,and that it was erected to his honour. In proof of thisopinion, he found within the circumference of the pillar amedal of Vespasian , in fine order.

Savary, on the authority of Abu’lfeda, who calls it “ thepillar of Severus, ” ascribes it to this emperor ; alleging, thathe visited Egypt, gave a senate to Alexandria , and deservedwell of its inhabitants. Accordingly, it is said that thiscolumn was a mark of their gratitude. The Greek inscrip-tion, half effaced, which is visible on the west side when thesun shines upon it, was legible, without doubt, in the time ofAbu’lfeda, and preserved the name of Severus . Nor is thisthe only monument erected to him by the gratitude of theAlexandrians. In the midst of the ruins of Antinoe , builtby Adrian, is seen a magnificent pillar, the inscription onwhich is still remaining, dedicated to Alexander Severus .

Denon has given a drawing of this pillar, with the markeddimensions of its various parts : he makes its whole height afraction more than 92 feet; and the height of the shaft,which is of a single piece, 63 feet l T 3 jj inch. It acquired,as this author says, the name of Pompey ’s pillar in the lothcentury. A monument, as he supposes, had been raised by