EDD

328

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take the rays which emanate from the whisperer’s mouth(which we shall suppose to be a point) in a horizontal plane,then it is evident, that they will proceed to the right and tothe left, and each particle of sound, as we may call it, forwant of a more specific name, will cut off equal segments ofthe circle which forms the section of the wall; or, in otherwords, will pass along equal chords ; and there will be aninfinite number of such reflections ; each particle describingchords different from those described by another, and an inde-finite number of these will divide the semi-circumferenceinto parts all equal to each other, in the same system ofchords; therefore, all the describing particles of sound passing| along the equal chords, will meet upon the other extremity ofthe diameter opposite the whisperer, and thus form a loudwhispering noise. It is evident, that polished surfaces are thei most favourable for this purpose. Accordingly, all the| contrivance requisite in whispering-places is, that near thei person who whispers, there may be a smooth arched wall,either cylindric or cylindroidic ; though a body with circularsections will do, but not so well.

! The most considerable whispering place in England, isi the whispering gallery in the dome of St. Paul’s Cathedral ,London , where the ticking of a watch may be heard fromj side to side, and a very easy whisper be sent all round thedome. The famous whispering gallery in Gloucester Cathe-: dral, is no other than a gallery above the east end of the| choir, leading from one side thereof to the other. It consistsof five angles, and six sides, the middlemost of which is anaked window; yet two whisperers hear each other at thedistance of twenty-five yards.

ECHOMETRY, the art of constructing vaults to produceechoes.

ECPHORA, or Ecphoran (from etc, out, and ipepta, I bear,')the projecture, or distance between the extremity of a mem-ber, or moulding, and the naked of the column, or other partit projects from.

Some authors, however, account the ecphora, or projecture,from the axis of the column, and define it to be a right lineintercepted between the axis and the outermost surface of amember, or moulding. The word is used by Vitruvius , inChapter III. book iii., in the explanation of columns andI their ornaments. See Projecture.

' ECTYPE (from the Greek): ap^ervurov, denotes theoriginal, or model; evrvtcov, the copy or image, moulded orj struck in creux; and etcrvicov, the image in relievo, or ern-l bossed.

! EDDYSTONE LIGHTHOUSE, a celebrated building ' erected upon a cluster of very dangerous rocks, situated inI the English Channel , in latitude 50° 3^ N., and longitude

i 40° 21' W. These rocks are about fourteen miles from

j Plymouth Sound, and, lying nearly in the track of vessels| going up or down channel, have been the cause of many' shipwrecks. To guard against these disasters, it was deemednecessary to erect a light-house ; but to effect this in a com-plete and permanent manner, so as to resist storms and affordlight, -was a task of extreme difficulty.

! The Eddystone rocks are so peculiarly exposed to the' swell of the ocean from the south and west, that the heavy1 seas break upon them with uncontrolled fury. Sometimes,

| | after a storm, when the sea is apparently quite smooth, andi its surface unruffled by the slightest breeze, the ground-swell,

! or under-current, meets the slope of the rocks, and the sea[ beats tremendously upon them, and even rises above thelight-house, overtopping it for the moment, as with a canopyof frothy wave. Notwithstanding this awful swell, Mr.Henry Winstanley undertook, in the year 1696, to build alight-house on the principal rock, for the rest are under

water ; and in 1700 he completed it. So confide 11 heingenious mechanic of the stability of his edifi ce >^ n( j 0 uSdeclared his wish to be in it during the most ^^tiii* 1 *^’storm that could arise. This wish he unfortunate*/ <je'for he perished in it, during the dreadful storm 1 o 0 f »stroyed it, November 27, 1703.

Another ligM-^frocfc

different construction, was erected of wood, 011 ^

by Mr. John Rudyerd, in 1709 ; which beii>o c °. n ^. f iy <

• i r r _ ii • J __ , _ u.r the jn” It.

file-

fire in 1755, a third, of stone, was begun by the ^jiish®brated Mr. John Smeaton , April 2, 1757, aI \ a t t!l •.August 24, 1759, which has hitherto withstood ^ 0 (’ tlj 1 ^of the most violent storms. The following accou,building, taken from Mr. Smeaton ’s ‘ Narrative,^^^ 0^read with interest, as a noble instance of the b>°’

skill, science, and perseverance over obstacles oformidable character :— . jgscrip 110 .

Mr. Smeaton begins his account with a genera .. git®*of the Eddystone rocks , the course of the tides, v i 9 iH n ®tion, component matter, and the proper seasonthem. He then takes an ample view of M r * . )(T u®“ eedifice, to whom he ascribes great praise lor * 1! ^j joip 1 ^taken and achieved what had been generally , e ... aS ter, e.jticable ; and after deploring that gentleman s ( ** jjudy® 1 .^on to describe the second lighthouse, built by 1 ^ ^

as a most complete edifice of the kind, being g x ing 11 jjthe course of which he details the best methods 0 s®

chains, and securing timber-work to rocks, wgive in his own words. _ f aC e ji-

“ As nothing would stand upon the sloping ^jjjyerdrock without artificial means to stay it, Mr. j e yel ^e

ciously concluded, that if the rock were reduce t i ie n 11 ^

ings, the heavy bodies to be placed upon it, ' v °® e caS e, e ' )( ,yno tendency to slide ; and this would jj n cr te a to*though but imperfectly executed ; for the s* 1 r ”<iuC e< Vj pybeing taken away from those parts that ' velt j j-gtai 11 ® t l>elevel, the whole would be much more 8eoa \ e ^, a tioOthe iron bolts or branches, than if, for the 1 ^JinSwhole, they had depended entirely upon the 1 ^ pa 1manifestly appears to have been the case ,, g pri® ’ e iiof Mr. Winstanley . According to Mr. R U1 1 ^ ba'’ einclined surface of the rock was intended ^ ha ve u )dreduced to a set of regular steps, which w vV hol e t \ ,e

attended with the same good effect, as i* * fi -0 ®?. fii*

which

good effect, as it tb ® ljt y, ,have been reduced to one level ; but ."‘certaiM/ ^hardness of the rock, the shortness and u t h** 6 .,.,intervals in which this part of the work d ltJ

performed ; and the great tendency of t* 1 ® ^ordh 1 # !the rock is composed to rise in spawls, J idoinclined surface, when work ed upon by t00 ‘!’ 0 fthe ' ,1/

• this P; 11 ^ pope 1 '*®

sufficient force to make an impression ;that is, the stepping of the rock, had been

D e* r ,

performed, though in a degree that suffice • , je9) apP j l0 lc 3

“The holes made to receive the iron biJ t"'®,

have been drilled into the rock byjumpe ’ of* 1 Imh 0

extremity gU rt* c . rf .0

of about 2|- inches diameter ; the — . tll „ - w _-

holes forming the breadth for the branc *> h°* e „„ra te ®

the rock, were about . adirected so that-at their bottoms they s > 90 ii'*®

somewhat better than an inch more, t (pird 1 po*®?full 8^ inches. In the intermediate space, th(

bored between the two former ; and tbel |j inn jels, tbl y>y

were broken into one. liv snuare-faced p , :nC 1,e .

7 x

»wke "the Toles l °suffi ’ •

™eans he obtained , , ent J/ sm ooth and reguJm.wide, 7i bro-id ot * ° 63 !l dove-tail shape, being j - c n^deep; aldasi e t t0p ’, 8 } at ^ttom, and 15 andwas forged to fit u° u d a °f be made all alike, eve f ^

c ° fit respective hole. The nun* P ie