Page:The Building News and Engineering Journal, Volume 22, 1872.djvu/57

 Jan, 12, 1872. good sense, easy assurance, and that happy boldness »of manner which goes rejoicing along the way where original merit often hesitates and stumbles. . . I doubt whether any man would take it as a compli- ment to be told that he painted a picture, planned a monument, designed a house, or laid out a garden as well as William Kent.” Now, assuming his history and portrait, his painted ceilings and staircases to’ haye been undistinguished by powerful invention, correct drawing, or harmony of colour, such lan- guage comes from an ill grace from one who should have known that Chantrey advertised at Sheffield in 1802 to take portraits in crayons, and that several examples from his hand haye been preserved in the town, more on accouny .f his after-fame in another branch of art than as striking likenesses. Chantrey, like Kent, and to his honour be it said, rose from a humble commencement to the height of professional fame. Mr. J. R. Smith, the Sheffield painter and engrayer, saw indications of ability in the young carver and gilder that induced him to give instruc- tion and advice. This prepared him for study at the Royal Academy, and by knowledge obtained there he was turned from an indifferent limner into a famous sculptor. With that Academy, and with British art in painting and sculpture, his name is destined to live for evermore. Cunningham would have been less displeased with Kent had he designed none of the monuments in Westminster Abbey ; and especially the one to Shakspeare, executed by Schee- makers for £300, in 1740. Walpole, indeed, led the van of criticism on this devoted work, by throwing upon it the odium of preposterous absurdity because the architect had thought fit ‘‘to place busts at the angles of a pedestal, and at the bottom of that pedestal” (they are Queen Elizabeth, Richard IL., and Henry V.). ‘This censure the biographer fails not to repeat. Butit is to be remarked that the sculptural part of the monument is raised on a podium, and the censured feature is not a pedestal at all, but an altar of the Muses on which are some books and a scroll. The ara, altar, and cippus, though distinct in original purpose, became very similar in form and ornament. They were frequently treated with great elaboration, and sphinxes, eagles, &c., are found at the base, where Kent has placed the masks. There is an altar in Thomson's monu- ment close by, and one in Dr. Woodward’s in the naye. Its occurrence in this latter case reminds one that altars were erected to gods, heroes, virtues, Vices, diseases, &c., and when Tiberius deprived them of the privilege of sheltering criminals one of Escu- lapius’s temples was exempted from the reform. Juno Samia, only else, was spared.* ——_—_>—___ ROYAL INSTITUTE OF BRITISH ARCHITECTS. T the ordinary general meeting of this Institute on Monday evening last, Mr. E, I’Anson, Vice President, occupied thechair. The ordinary routine business having been transacted, Mr. F. P. Cockerell. Hon. See. for Foreign Correspondence, read a letter from Professor Donaldson, respecting some drawings at Naples and Milan, and Mr. W. S. Paul was elected an Associate. Among the donations to the library was Mr. Street's recently-published brochure in reply to the critics of his designs for the New Law Courts. Regarding this pamphlet, Professor Kerr said that reference was made therein to Mr. Street’s invitation to the members of the Institute to inspect his plans, and he (the Professor) wished to know whether the Institute was supposed to be committed to any views regarding the design. He suggested that the drawings should be exhibited at the Institute. Mr. EAstiake, the Secretary, explained that Mr. Street’s invitation was not to the Institute as a body, but to its individual members, and therefore did not eommit the Institute to any expression of opinion. Sir Grorcr Attryne, Barr, then read a paper (of which we gave the substance) ON THE TRAVELLING STAGE USED IN THE ERECTION OF THE ROOF OVER 8S. PANCRAS STATION, Inestimating for such aroof as that at S. Pancras, the first and most important consideration was—how it was to be fixed, the principal rafters being 240ft. clear span, and 100ft. high. Sideways these main ribs or principals may be said to be without lateral strength. To consider the whole structure as a great wrought iron arch, and put a timber cen- treing strong enough to carry it through the whole length of the station, would not do, because the enormous cost of the timber, and the labour of fixing mental sculptures in the museum of the Louvre, in 1828, where such decoration may be found, as well as in other works on altars. THE BUILDING NEWS. it, would be much too expensive. To put up a cen- treing for the length of eight principals; this num- ber is taken, because the wind ties, which start on the first principal, do not reach the wall, or get any connection to it, until this point is reached. Put- ting up such acentreing, and pulling it down, and building it up for the next, would take too much timber, Jabour, and time, and was in its turn abandoned. It then became apparent that the best, most secure, and most economical system would be to put a centreing on wheels right across the whole station wide enough to take two principals and leave room for the men to work outside. The principals being 29ft. 4in. centres, the width of 40ft. was adopted, and the system decided on of making the staging move on wheels, from rib to rib, with such arrangement of its parts as would allow it to collapse after it had done its work at one rib and was re- quired at thenext. This was doneby the timber slides described hereafter. The stage being fixed opposite the two first ribs, when these two ribs were fixed with | all their purlins, how were they te be held safely while the stage is moved to the third and fourth or the second and third? In the first instance, Sir George saw no other way out of the difficulty than by having two stages, which plan he adopted; and the much-improved method of dividing thestageinto three parts did not come into his head until he began to consider that there might be some difficulty in moy- ing such a great machine and keeping it square on the rails, the plan at this period being that the first stage should be left standing and bolted down to the floor opposite principals Nos. 1 and 2, which would be fastened firmly to the stage by the timber slides. The second stage would then fix three and four, and fasten them by their purlins and wind ties to No. 2, and move to 5and 6. When No. 8 was reached the wind ties could be fastened to the walls, and this part of the roof would be in all ways self-supporting. No. 1 stage could be moved up to No. 9 rib, and No. 2 could be rolled forward to No. 11, and four ribs could be worked on at once. On considering the difficulty of moving these wide and long stages, 40ft. by 208ft. 10in., the author determined to divide them into three parts, and to move each part separately. The idea immediately struck him that he could by this system do away with and save the expense of the second stage altogether by fixing the three parts together opposite to ribs Nos. 1 and 2, bolting them fast together and also screwing them down to the floor, and placing chocks nnder the main horizontal frames, so that the strain from the holding-down bolts should be taken off the wheels, and all tendency to move prevented. The ribs Nos. 1 and 2 would be fixed with their purlins and all complete ; the centre part of the stage would remain screwed fast to the floor, with its timber slides hold- ing fast to the rib; the bolts holding the side pieces or wings to the centre compartment and those hold- ing them to the floor would be removed, the chocks would be knocked out, the timber slides drawn in, and the wings would be free to move; they would move with their outer slides opposite No. 3 rib; their inner slides would hold on to No. 2 rib. They would then be screwed fast to the floor as before. The centre compartment would then in like manner be set free, move up toribs 2 and 3. The whole staging would again be screwed together, and to the floor as before, and No. 3 rib would be fixed. The wings would then move to No. 4, the centre follow, and they would go on to the end of the station. This plan of working, however, did not suggest itself until the cast-iron couplings and wheels where made for both stages. Main Horizontal Framing.—The main horizon- tal fraiming is formed of double timbers, the section being 6ft. by 12ft.; the axle-boxes of the wheels were fixed to them, allowing the wheels themselves to run between the timbers at right angles. To these are laid the cross framing, consisting of tim- bers 12in. square. ‘These are firmly bolted to the lower double framing, and on the upper 12in. square timbers are bolted the cast-iron sockets for carrying the uprights and diagonals; under the uprights the wheels, 2ft. Gin. in diameter, are fixed; under the main uprights in the centre stage, where, from the height of the uprights and the increased weight of this part of the stage itself, the wheels are doubled; inorder to distribute the weight as evenly over the floor as possible, the wheels are so arranged as to have a weight of about five tons on each, caleula- ting from the centres of uprights. The whole three stages are 207ft. din. long and 38ft. wide, giving a platform 208ft. 10in. long and 40ft. wide. Horizontal Framing Wheels.—The wheels are distributed as follows :—Under the main uprights of the centre compartment are seven rows, of nine wheels in each row, making 63 wheels; under the side stages there are six rows, of five wheels in each row, making in all for the side stages 60 wheels: | 41 —eeaunaaaqaqaq que” oo eeweTeTeT eee eee eeeeeeeeswv uum” which, in addition to those of the centre stage, make a total of 123 wheels. The horizontal framing is firmly braced in all directions by diagonal bracing, to prevent any tendency to twist. The whole stage is fixed on nineteen lines of rails. Uprights.—Two sets of timber uprights are placed under each rib. The weight to be carried of each rib with its purlins and wind ties is about 100 tons. There are in the centre compartment, under each rib, in all 14 uprights, that is to say there are 2 rows with 7 uprights in each, making 28 uprights in all; in the side compartments the same double row of up- rights is continued, there are 6 uprights in each row —2 rows under each rib, making 24 in all; the other side compartment has the same number, we have then in the centre compartment 28 uprights; in the east wing 24; andin the west wing 24; making in all 76. The dimensions of the uprights are 12in. square. They are 22ft. 8in. long; at this point they are fittedinto acastiron cap or socket; the lower part of this socket fits the first upright which is 12in. square. The next tier is reduced to 10in. square. The 10in, square uprights are 29ft. 2in. At this point they are fitted into a cast iron cap, the lower part 1(in. square, while the top is reduced to 9in. square, and this dimension is continued to the top of the stage. The whole stage is arranged as it passes under the ribs in steps or platforms, the height of these from the floor and their distance from each other is governed by the position of the joints in the main ribs. Each of these platforms is fitted with the timber slides, one set for each rib; they clip the main rib firmly, they haye a lateral moyement as well as an outward, they move laterally on the wallings, and are not screwed down until the exact position of the ribs is ascertained. Their outward movement is regulated by the folding wedges which are driven between them and the main uprights. Uprights and Wallings.—At a height of 13ft. 4in. from the rails the first line of wallings is fixed; these run in a direction at right angles to the main ribs, or longitudinally with the station; the section is 12in. deep by Gin. thick. Immediately above them are the cross wallings; this line of wallings is 14ft. din. from the lower side to the floor. At a distance of 14ft. din. again above these, at the point where the vertical timbers are to be reduced from 12in. to 10in- square, the second floor of horizontal bracing is intro- duced; at 14ft. 4in. above this is the third set of wallings, and at 14ft. 4in. above them is the fourth set of wallings and the third horizontal bracing ; at this point the timbers fare reduced to Yin. square. The centre compartment has seven sets of wallings and four floors of horizontal bracing. The side or wing stages have five floors of wallings and three * floors of horizontal bracing. The wallings are in all cases double, that is one on each side of the vertical timbers. : Diagonals.—The whole stage is braced strongly with diagonals; these are so arranged as to abut against the main verticals and the wallings. The wallings being double and fixed on each side of the verticals, the strain from the diagonals is kept central with the verticals ; a short cross-piece is fixed across the wallings at the point where they are fixed to the verticals to receive the end of the diagonals. To pro- vide against the shrinking of the timber an arrange- ment is made for wedging up the diagonals, in all cases on the top of the diagonal; in this way any shrinkage of the timber is shown by the wedges getting loose; if the weight of the diagonal rested on the wedges a shrinkage would not be observed until the diagonal itself was loose. The staging might give way and lead to considerable inaccuracies in the work. The diagonals are in all cases of the same section as the verticals against which they abut. The diagonals are so arranged that the heavy strains from the dead weights, and those produced by wedging out the slides which come vertically or horizontally on the wallings and verticals, is distributed by them, the diagonals, throughout the whole staging. Quantities.—The ironwork in the whole of the three compartments amounts to about 80 tons—0 tons of cast and 30 tons of wrought iron. The timber in the side stage is as follows :— Oub. Ft. 24 verticals, 12in. by 12in., and 9in. by 9in...... 12074 27 transverse wallings, 12in. by 6in., and 10in, DY. Sid... .c.ceeecoscccenncnacsvesneanssrsesnsonsenccese 11214 26 longitudinal wallings, 12in. by Gin., and 10in. by 5in., and 9in. by 44in. 1009 55 platform joists or wallings, 9in. by 44 307 120 transverse diagonals, 12in. by 12in,, and 9in. by 9in 1431 122 longitudinal diagonals, 12in. by 12in., and Yin. by 9in eos 14183 5 platform floors, 3in. thick. 770 10 sets of timber slide 380 8sets horizontal bracing. 576 Battens, joint-pieces, &c. 119 83392 For two wings 16,679 cubic feet.
 * Mr.T. L. Donaldson described a selection of orna-