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similar manner the stones of the base courses were markedby lines drawn parallel to the length of the steps, and othersprependicular to the same, the crossings being sawn in, asbefore described. There was, however, a nicety in this partof the work, that required particular attention, and that wasin forming a provision for setting the four radical stones,that occupy the four radical dovetails into which each stepwas formed, as maybe observed in the several figures ofPlate III. Those stones were formed, from the work of therock’s being actually moulded off, and from the manner,already described, of bringing those moulds to agree afterthey were brought home from the rock, those stones werelaid upon the platform thereby, and then marked with linesupon their own substance, in the manner just mentioned: andas the distances of each of those stones were then ascertainedby gauge-rods of white fir-wood, while upon the platform ; itmust be expected, as each step was reduced to a level plain,as the platform was, that when laid upon the rock in theirdue positions and distances, by the gauge-rods, they wouldnearly fit the dovetails that had been cut in the rock toreceive them; and where there was the least want of fitness,as might possibly happen with bodies of so rigid a nature,either the stone or the rock was cut, till each stone wouldcome into its exact relative position, and then all the restwould follow one another by their marks, in the same manneras they had done upon the platform.

“ It is necessary to be noticed, that the waist of each pieceof stone had two grooves cut, from the top to the bottom ofthe course, of an inch in depth, and three inches in width:applicable to those grooves were prepared a number of oakwedges, somewhat less than three inches in breadth, than oneinch thick at the head, nearly three-eighths thick at the point,and six inches long. The disposition of these grooves isshown in the courses of Plate III. where the little blackparallelogram figures, placed along the lines describing thejoints of the courses, represent the tops of the grooves, andtheir place on the right hand or left of the joint line show inwhich stone the groove is cut. It is also to be noted, thatwhere the flank side of a stone was not more in length thana foot, or fourteen inches, one groove was generally deemedsufficient; but those of eighteen inches or upwards had,generally, in themselves or the adjoining stone, a couple ofgrooves.

“ The mortar was prepared for use by being beat in a verystrong wooden bucket, made for the purpose; each mortar-beater had his own bucket, which he placed upon any level partof the work, and with a kind of rammer, or wooden pestle,first beat the lime alone, about a quarter of a peck at a time,to which, when formed into a complete, but rather thin paste,with sea-water, he then gradually added the other ingredient,keeping it constantly in a degree of toughness by continuanceof beating. When a stone had been fitted and ready forsetting, he whose mortar had been longest in beating camefirst, and the rest in order: the mason took the mortar out ofthe bucket; and, if any was spared, he still kept on beating;if the whole was exhausted, he began upon a fresh batch.The stones were first tried, and heaved into and out of theirrecesses, by a light movable triangle, which being furnishedwith a light double tackle, the greatest number of all the piecescould be purchased by the simple application of the hand;and this made our stones to be readily manageable by suchmachinery as could commodiously be moved and carried back-ward and forward in the yawls every tide. To the first stone,and some few others, we took the great tackle, that wemight hoist and lower them with certainty and ease; butthere were not in the whole above a dozen stones thatrequired it.

“ I he stone to be set being hung in the tacKie, , j,e3'of mortar spread, was then lowered into its place, an ^.jtdown with a heavy wooden maul, and levelled vrttn ^s, ^level: and the stone being brought accurately to it 9 ,® po'twas then considered as set in its place. The ^ usll ^; n g tb swas to retain it exactly in that position, notwithstan jlieutmost violence of the sea might come upon it be n otfmortar was hard enough to resist it. The carpeh fiei,dropped into each groove two of the wedges already d ^ s°one upon its head, and the other with its point doW® a( j 9that the two wedges in each groove would then he ® ^ jjgflpoints. With a bar of iron of about two inches t gnd 9broad, three-quarters of an inch thick, and two f® ff |tb 9half long, the ends being square, he could easily 1 ggptl/rammer) drive down one wedge upon the other, ve ^qua^/at first, so that the opposite pairs of wedges s toIie

tightened, they would equally resist each other, andwould therefore keep its place; and in this ® ar ^ er e ^wedges might be driven even more tight thanoccasion for; as the wood being dry, it would by jjivioSjbecome tighter; and it was possible that by too nine tyok en ’and the swelling of the wedges, the stones might 9

and farther, that a moderate fastening might be ®. a t tb ecouple of wedges were also, in like manner, p ltc poi ntop of each groove, the dormant wedge, or that vvi ffe( jge, 0upward, being held in the hand, while the dr® er ; tPthat with its point downward, was driven with a na ^ st° awhole of what remained above the upper surface a co u P fwas then cut off with a saw or chisel; and genera '^,#1^of thin wedges were driven very moderately at th®^the stone; whose tendency being to force it out o^ p te settail, they would, by moderate driving, only tend vi°* ethe whole mass steady together; in opposition toagitation that might arise from the sea. , , c t ba^

“ After a stone was thus fixed, we never, i® ^ theinstance of its having been stirred by any a ® tl .° nC e th er< Lf

whatever; but, considering the unmeasured vio a ltog et ,

the farther security by trenails will not se ®® e wa s * jt,unnecessary, when we reflect, that after a s ^ np° n g]) tfixed in its place by wedges, a great sea co “ g hii>g g(often in less than half an hour) was capable oall the mortar from the bed underneath it, nl |j ier wi se ’ ( jjgevery defence we could give it by plaster or o gga a(that when the bed of mortar was destroyed, to ®

c »se

U P. that the sam J01nt,Woul(1 exert the same pobroad base waiT turne/ 0 *^- exert to overset it, i«hedges only fixed ■>„,/ Upri g ,u to oppose it; aI1 ^ ffJ „.each course consist a ^ Securec * the several pieces - tokeep the whole » n 6 ’J° ea<dl other, and had no ten ^jgshould lose its morf 96 vT together, in case the ^

sury to have s nm ai ' Jed ’ i(: seemed therefore highf j l0 !e

of a couZ 2 m ° f Panting the lifting J tb e

mortar should totally’ S ° U f ky C ° ntl ” Ad^'f

now to what r, take awa y that tendency■ J \ ! e e^

trenaib of on? T ’ that a C0 V of holes, to recedehored in the w i. ln ° 1 and three quarters in d/a 1 ®/ 3 „ et> d

of every piece'of throu g h the external or P r0 ^ eset in their sfon , e: we must now suppose th t irrners, witl, f e “’ * nd fixed hy wedges; then one o fte

stone of thpp J m P® r > began to continue the hoi® jiifl 9

inchts de * ?T?. ehw > and bored it to about eight oreighth of ™ - U this hole was bored of a lessstone a b L . I,1Ch W di ^ter, than the hole thf* ^viouslv dressed" coase< l ue " ee , the trenails, having ^

freely through “ plane tlJi they would i° t0

“nder one and U ?, per hoie ’ wouId drive mi^ P

> generally would become so fast as