It;
ifr
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334
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there the 8th of September, was informed by Mr. Jessop,that the preceding evening, there being a very strong tide,and no wind, a West-Indiaman, homeward bound, and aman-of-war’s tender, were in great danger of driving uponthe north-east rock ; but that he timely perceiving theirdanger, though they themselves were not aware of it, orderedout the seamen and hands, who towed them off.
“ On this visit, I staid two days ; for as the working com-pany had begun to take down the upper part of the rock, itwas necessary to concert, and put in practice, the propermeans of doing that, without damage to what was destinedto remain. I have already mentioned my resolution of notusing gunpowder ; yet it was necessary, for the sake of dis-patch, to employ some means more expeditious than the slowway of crumbling off the matter by the blunt points ofpicks. It has been already noticed, that the laminae com-posing the rock were parallel to the inclined surface : and itwas very probable that the chasm into which Mr. Winstan-ley’s chain had been so fast jambed, that it never could bedisengaged, extended farther into the rock than the visibledisunion of the parts : this made me resolve to try a methodsometimes used in this country, for the division of hardstones, called the hey and feather, in order to cross-cut thisupper stratum of the rock. The construction and operationof the key and feather is as follows :—A right line is markedupon the surface of the rock or stone to be cut, in the direc-tion in which it is intended to be divided. Holes are thendrilled by a jumper, at the distance of six or eight inches,and about one inch and a quarter in diameter, to the depthof about eight or nine inches ; the distances, however, ofthe holes, and their diameters, as well as their depth, are toto be greater or less, according to the strength of the stone,in the estimation of the artist directing the work. Theabove dimensions were what we used on this occasion.The key is a long tapering wedge, of somewhat less breadththan the diameter of the holes, and so as to go easily intothem ; the length being three or four inches more than thedepth of the holes. The feathers are pieces of iron, also ofa wedge-like shape ; the side to be applied to the key beingflat, but the other side a segment of a circle, answerable tothat of the holes; so that the two flat sides of two feathersbeing applied to the two flat sides of the key, and the thickend of the feathers to the thin end of the key, they all toge-ther compose a cylindric, or rather oval kind of body; whichin this position of parts is too big to go into the holes by atleast one-eighth of an inch; that is, in the direction of adiameter passing through the three parts; but, in the otherdirection, is no broader than to go with ease into the holes.A key and a pair of feathers is made use of in each hole ;and the feathers being first dropped in, with the thick endsdownward, the keys are then entered between them ; theflat sides of all the keys and the feathers being set parallel tothat line in which the holes are disposed : the keys are thendriven by a sledge-hammer, proceeding from one to another,and being forced gradually, as in splitting of moor-stone, thestrongest stones are unable to resist their joint effort; and thestone is split according to the direction of the original line,as effectually, and much more regularly and certainly, thancould be done with gunpowder, and without any concussionof the parts. Had our rock been entirely solid, this way ofworking might not have been applicable, on account of thecrack’s going too deep; but here, when it arrived at the jointwhere the chain was lodged, the split part became entirelydisengaged from the rest ; and in this way we were enabledto bring off the quantity of several cubic feet at a time : andthus the chain was released, after a confinement of abovefifty years. The impossibility of disengaging it before now
appeared very evident; for the pressure had ^ eeI ? S f t f,e li^ 9the rock’s closing upon it, as before suggested, tha ^ c oH>'in their intersections were pressed into each ott> e > j, 0 lt-pletely as if they had been made of lead ; though^ s 0 f adiron composing the chain,- had been at least five-eig
the
roc 1
e»t
The l°' vl nlo'vew
inch in diameter.
“ On Thursday, the 16th, I again went off toand found the work in the following situation. ,
new step (the most difficult to work upon, because * r0 ugb'with its dovetails quite completed. The second s r.^ 9 tePbedded, and all its dovetails scappelled out. I he, A^ed , aI1(being the lowest in Mr. Iiudyerd’s work) smooth- e g tnt e 'all the dovetails roughed out. The fourth in the aI1 dtl> eThe fifth rough-bedded, and dovetails scappelled ° U (r j ie< J <$'sixth smooth-bedded, and all the dovetails /nf’thSLastly, the top of the rock, the greatest part in d-f eawhereof had been previously taken down by the *ther method, as low as it could be done with P l °,? ce of * 1now to be reduced to a level with the upper sur ^ fora 1sixth step ; the top of that step heing necessa* 1 7 r9 e; 9part of the bed for the seventh, or first regula 1 r octhat what now remained, was to bring the top a ppe* re g ’to a regular floor by picks : and from what now me
(as all the upper parts, that had been damaged by ,were cut off,) the new building was likely to rest Wbasis even more solid than the former had done. „ tb eOn Thursday, the 30th, I traced the outlines up C|
upper part of the rock for the border of the seventh c be
all within which was to be sunk to the level of the W P forsixth, and all without to be left standing, as a b° r . a riddefence of the ground-joint of the work with the roc* th emeasuring the height of the top step above the be? ^ldfirst, I found it to be eight feet four inches; i 0 we si
now be the difference of level between the wester
tlle new building, and the east or highest. , 0a cOI he setting in of the equinoctial winds preven on ^farther progress in the work for this season ; 0 der» te ’tth of November, the weather being somewhat ^ten 9 *Mr. Smeaton went off in the Eddystone boat, witn rot*and the carpenter, to mould off the dovetails fvon \L upP erwhen he found “ four or five of the dovetails m * IIia n/step wanting some amendment, that would enap’°T_ t p;t(men at each, for about four or five hours. The ^ re j Jl t-of the top of the rock was now brought to a rreg . „ do''*!but some part of the north-east side wanted bu n o gn de“_'to a level.” And here the operations for the, y®‘ , g j-oc »for, on the 15th of the month, the workmen leit halthaving been able to make only thirty-eight hourssince the 2nd of October.
d ^
the next wortfi]!^!^ 163 tfl ® interval between m® r . .his mason’s vuv? t/’ 801 ? ' VItfl describing the regal j
the followi^^ 3126 f ‘he stones!
“From tht i " ma y he useful to the reader. n tol
maxim, that on S ' mwg 1 “/ways laid it down ns a f an ‘j t j,er t0
suit our purDnvpa C / ou l lt °f the precariousness of ' y . t j,;nk
it has alre ^ ’ C a "d without its being favourable, ^
' ’ - *■ ^
^ UUVi UllUOUV - . f\(T
ady sufficiently appeared, that noM^n
l be 1
trorkJSTa
npon tlieEddystoug \ “ ,,
the rock, bv " We cou id save one .
always prove wee ^ in our work-yard, tf ' ve ,y-
thing oimb, . ‘ purchase ; and that therein c0l dd
tend to the mm’ 6 * ° ne ^ wa 7 of preparation, whi‘. a l,l j
certainty in fi ' n f,. 0ur wor h together with ex P e '! lce ;f °r thi/p urpose U . t,mate falng of it in its proper pj ^
and heavy pieces of .I™ 8 nec . essar 7 t0 make use Lstone, were lib i . sf ° ne M > in such a situation as jtbo 11^nningZ ca P a We of heing managed *