EDD

342

EDD

between, tended to open the joint, so that it might alwaysremain leaky, in a greater or a less degree ; for we know ofno degree of separation of parts, however minute, shortof absolute contact, which will stop or prevent the percola-tion of water. For this purpose I conceived, that if flatstones were introduced into each upright joint, so as to belodged partly in one stone, and partly in its neighbour,(much upon the same idea that Dutch laths were formerlyintroduced into the joints of chamber floors, to hinder thepassage of wet,) the. water might be prevented from makingits way through the upright joints of the walls.

“The manner in which it was executed was as follows:(see Plate IV. Figure 6.) At each end of each stone,answerable to the middle between the inside of the wall andthe outside, was sunk a groove, two inches and a half wideand three deep, running from the top to the bottom: when,therefore, two contiguous pieces of stone were put togetherin their places, the two grooves being applied to each other,they would form a rhomb of six inches in length, and twoinches and a half in breadth, which in this state would bean unoccupied cavity from the top to the bottom of eachcourse; the rest of the joint, where the surfaces of the twostones applied to each other, was made good with mortar inthe ordinary way, and brought together by the gentle blowsof a beetle. For the groove mentioned, a solid rhomb wasprepared, of about two inches thick by five inches broad,and in length a little less than the depth of the cavity, whichgenerally was eighteen or twenty inches ; and for the sakeof the firmness of those slender pieces of stones, I madechoice of the flat paving-stones from Purbeck, which is alaminated marble of great strength and solidity. The joint-stones (which was the name we gave those rhombs) thusprepared, would readily go down the cavities ; but, to fixthem solid, a quantity of well-tempered mortar was prepared,made more soft than ordinary, by the addition of a littlewater ; a competent quantity being put down to the bottomof the hole, the joint-stone was put down upon it, and, bythe simple pressure of the hand, was forced down to thebottom, causing the semifluid mortar to rise up to the top,and completely fill the cavity : and, when forced down inthe way described, having in this state a small quantity ofsuperfluous moisture about it, a few very gentle blows, orraps, were given upon the top of it by the handle of amason’s trowel, which, producing a small degree of agitation,while tlie dry stones were absorbing the moisture, contributed(like the beating of mortar) to bring all the parts into theirmost friendly state of contact, and, in consequence, to theirfirmest state of union ; and this happened in the course of afew minutes, so that no farther agitation could be of anyservice.

“ As the cramps, that were to bind the contiguous piecestogether, must cross the joints upon their upper surface, theywere of course to be applied alter the joint-stones weresettled in their places. Precaution was therefore necessarynot to apply too much exertion in forcing down the joint-stones : for, however gentle the operation may appear,according as it has been described., yet it was found advisablenot to put in the joint-stones till an additional piece hadbeen got down upon its joggles, and plain-jointed at eachside of the two pieces, whose joint-stone was to be put in ;for, by this means, there were the united efforts of all thejoggles, and adhesion of the beds of two stones on each sideof that where the effort was applied. Without any atten-tion to this, the lateral force arising from merely pressingdown a joint-stone, was capable of breaking the adhesion ofthe joint where it was applied.

“ The cramping was applied the last thing. The top or

flat bars of the cramps were about thirteen inches ’^ e reinches broad, and five-eighths of an inch thick. a j er ,gtb >turned down at each end about three inches id ^ informing a cylinder of one and one-eighth of an u po 9diameter. Jumper-holes were previously bored w guf

the platform, and the cramps fitted to their places > _p oU rtl> 3face of the stone under each cramp being sunk *k re ® jgtelyof an inch, so that the two stones together would co y ga ;dreceive, or rather bury, the cramps: the joint-stones* ^ t Jieabove, being made so much shorter than the heig Th ecourse, as not to interrupt the bedding of the cr , ( a3

places for the cramps being properly fitted and c e ^ j n awe now were not liable to be driven off the w O ppot'moment, as had formerly been the case,) we took p9 o*tunity, whenever time allowed it, of fixing the c ^ tb ea whole course together. There was no dange ^ gr ecramps not fitting; as, besides that all the cra®P a t fb eforged to fit a gauge-bar having a couple of h° . tb e ' rassigned distance, they were also fitted and mark .^fbrD 1,particular places at Mill Bay, while upon the PEvery cramp being now ultimately tried to its P 19 ^’ gj-aa'Pthen put into a kettle of lead, made red hot ; an s p o0^ a

continued there till it was also reddish. Abou c ra<°Pof oil was poured into the two cramp-holes, an ^gd bl

being put into its place, the ebullition of the oi> gUr fa ce ’the heat of the iron, quickly gave a complete ot y ocC up>?not only to the whole cramp, but to the whole u ^ g{l it,cavity in the stone; then the hot lead being p° ul ^^ ( j 0 gcapfthe unctuous matter caused the metal to run into gr e »othe most minute cavity unfilled, and completely to tb

cramp ; and they became by this means defence up°^salts of the sea, even had they remained uncor e( j coafMr. Eudyerd’s principle. Mr. Eudyerd had bal'd ^pewter. The lead we used was slag lead, wbic arn ps, aS \and stiffer than fine lead: and, as we used no c ooP1 i°° ’essential part of the building, till above the stor ^ er e t0

I judged pewter, merely for the sake of st *®' ne , S3 ’ c0 urs eunnecessary. By cramping, in general, a who e( ,tl—_ .1-* „c WOUin e ,

m

(re-

ady

3*

its

tbe

ther,. the contraction of the iron in cooling wo n( j toto the tightness wherewith every stone was /^ e gide 9 efellow. Thus, according to this mode of fixing. „ v iol e

. resist an

union of the parts by the mortar itself,) to r ®f t j ie in- ^y‘ranveme.nt whilst it was doing, and be o nl

and derangement whilst it was doing,tion of the mortar, every course was

aim . pis^“

re, * ine ,.‘”

sixteen joggles, and each single stone by j^ ach otb® 1 ^at its lower bed ; they were farther steadied co< !0 P t a‘ e c'the joint-stones, and lastly by the cram P s ). W roV ed 90 6 { ofprevented a separation; and this method P derang<>/tual, that we were not only free from all g n d a ,j gI ~the stones, when in their places, but Id* j ue co 091 t pejoint, except one, in the whole building. / reI) ces t0 1 ’

ation of Plate IV., with the particular re ? nte ijjgibl|yjjl.

whole of this process will become perfectly ***

Ct A.. C* i_1 .1 O AiL _ C Ccntomhl^ri Vfc/O ../iTl ^

wb>:

cb

“ On Saturday, the 30th of September, g upon 'j,was completely set ; and, being the firS L G the ceiling® pgr®was rested the vaulted floor, which mad . aB d, a gSstore-room and floor of the upper store-roo in

nonin n/innnnnJ n Jitf/mnn/in Ifl tllft 1110(16 ^ C

again occurred a difference in the mode o o p th® tb 9 *in all like cases, I attended the performan ^ c bai ’pel

and that was the leading-in of the firs- ® 0 f tb® pel"

was lodged in a groove cut round the mi _ .^pctor 1surface of this course, which this day w t j ie 1 st ’,

formed ; and the next day, Sunday, Oc o ; n also > e t

XXIX. was set, and its circular chain lean p rop® r ^r 9 **operation, with the reason thereof, it w * gever 9 tb®describe : The ordinary way of fixing bond 111 ®by joggles and joint-stones, and also