410 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[December, 



consisting of a cog wheel, working into the cogged rail, attached to 

 the machine by the aid of one man standing upon each stage. This 

 travelling crane or crab, which has received some important improve- 

 ments from Messrs. Grissell and Peto, is the most important machine 

 a builder can have for erecting buildings where there is masonry ; by 

 it the stones are lifted oft" the truck, raised, and lowered immediately 

 on to their beds, and adjusted with the aid of a mason and his la- 

 bourer only, besides the two labourers with the machine, by which 

 means great economy in labour is obtained. As soon as the erection 

 is brought up to the level of the first stage, the next story of scaf- 

 folding is erected, and then the "traveller" is removed up to the top, 

 and so on until the whole construction is finished. 



This description of scaffolding was first introduced into use by 

 Grissell and Peto in the erection of the Reform Club House in Pall 

 Mall some three years since, and was found to possess so many advan- 

 tages over the ordinary scaffolding made with poles, that it is not only 

 used by them at the New Houses of Parliament and in all their other 

 heavy contracts where masonry is chiefly concerned, but is coming 

 into general use bv other large builders, as at the Royal Exchange, 

 Sun Fire Office, and the new Club House in St. James's Street. Its 

 stability has recently been tested beyond all doubt at the Nelson Co- 

 lumn, both as to its resistance to wind at a great altitude, and in its 

 strength and steadiness while hoisting heavy weights. One of the 

 parts of the statue of Nelson weighed 12 tons, and the load, although 

 eight hours upon the scaffolding, did not occasion the most trifling 

 vibration to be observable. 



One of the advantages of this mode of scaffolding is, that the 

 timber is all convertible for the building at which it may be used, as 

 the scaffolding maybe dispensed with as soon as the carcase is covered 

 in, and it is generally used up in the internal carpentry of the build- 

 ing; the enormous waste in scaffold cords is also avoided as well as 

 the considerable expence of a number of masons' labourers, who are 

 always necessarily in attendance upon a scaffolding of the ordinary 

 kind during its use. 



Before we close this description of the scaffold, we must not forget 

 Mr. Allen, the indefatigable foreman of the masons of Messrs. Grissell 

 and Peto, under whose able directions the scaffolding of the Nelson 

 Memorial was erected. 



The foundation of the column consists of a bed of concrete resting 

 upon a bed of gravel, upon the concrete is carried up brickwork of 

 hard stocks set in cement ; the column is solid and constructed of 

 granite from Dartmoor, each course consists of seven blocks, one in the 

 centre forming an oblong square, the others have the joints radiating 

 from the angles and middle of the centre block, and each block is 

 dowelled together vertically with slate dowels. The bell of the 

 capital is also of granite, to which are fastened the enrichments and 

 volutes, which are of bronze, executed by Mr. Clark of Birmingham. 

 The cippus or pedestal upon which the figure stands is likewise of 

 granite. The figure is sculptured by Mr. Baily, the eminent sculptor; 

 it is of Cragleith stone from the Liver rock quarry at Granton in Scot- 

 land, belonging to the Duke of Buccleuch ; it is of a dark brownish 

 tint and very hard: it is in three parts, the lower block forming the 

 plinth, the bottom part of the figure and the capstan at the back, 

 which is represented with a rope coiled round it, is said to weigh 12 

 tons, and originally when the block was removed from the quarry it 

 weighed 30 tons, and formed part of a block 45 tons weight in the 

 quarry, (see Journal, Vol. V., 1S42, p. 230 and p. 284.) The figure is 

 fixed to the pedestal by a dowel of York stone 1 foot inches long 

 and 10 inches square, half let into the top of the pedestal and the 

 other half into the plinth of the figure. The other parts of the 

 figure are connected with similar dowels. The figure, we understand, 

 has been coated with oil and wax, which gives it its present dark ap- 

 pearance, but it will ultimately get lighter. 



The following particulars show the time occupied in raising the 

 lower block of the figure, it was adjusted on the ground on the 3rd of 

 November, at 5 h. 20 m. a.m. — it reached the first stage at G h. 45 m., 

 second stage Sh. 8 m., third stage 9h. 25 m., fourth stage 10 h. 23 m., 

 top lib. 20 m., total time six hours; it was removed horizontally from 



the end of the scaffolding to the centre in two minutes, and com- 

 pletely set in its place at 11 h. 45 m. 



The landings and the steps surrounding the base are laid upon brick 

 arches, and the plinths at the angles are to be surmounted with lions 

 couchant, aud the panels of the pedestal to be filled in with bronze 

 bas-reliefs representing the. heroic deeds of Nelson. In our 2nd vo- 

 lume, p. 279, will be found an engraving of the original design. 



In conclusion, we cannot speak too highly of the manner in which 

 the works are executed. They do the greatest credit to the establish- 

 ment and enterprise of Messrs. Grissell and Peto. 



Annexed we have given a table showing the measurements of the 

 details. 



Details of Column. 



Figure of Nelson 

 Plinth of ditto 



Cippus, or Pedestal upon which the figure s 



7 ft. Gin. diameter, 

 Base of ditto, 8 ft. 8 in. diameter 



height. 

 n. ft. i 



3 5 



1 6 



Column : — 



Abacus of capital . . . . . . 2 



Bell of capital in 4 courses, 1G ft. across the volutes 10 

 Top course of column with annulus, 9 ft. diameter top 



of shaft .. .. .. .. 3 2 



10 courses below 2 ft. 7 in. each .. .. 25 10 



9 ditto 2 ft. 11 in. .. .. 26 3 



8 ditto 3ft. tin. .. 26 8 



Lower course (10 ft. G in. diam.) including [the upper 



torus of base . . . . . . . . 3 6 



Scotia and lower torus of base . . . . 2 7 



Plinth of base, 14 ft. square .. .. 1 10 



Height of shaft, base, and capital .. .. 



Peoestal: — 



Scotia above . . . . . . . . 3 6 



Moulded cornice and dentill .. .. 2 3 



lied moulding and upper course . . . . 2 3 



6 courses, 16 ft. square, 2 ft. 4 in. each .. 14 3 



Lower course and part of moulding . . 2 7 



Moulded base . . . . . . . . 2 2 



Plinth under ditto, 22 ft. square .. .. 2 8 



Height of Pedestal .. .. .. 



Top step below pedestal, 27 ft. G ft. square .. 3 



Lower ditto 33 ft. . . . . 3 



Height of two steps . . . . . . 



Solid brickwork in cement to foundation of column, 52 ft. 



square at base, 1 ft. 6 in. high, then gradually diminishing 



all round, 12 ft. 6 in. high to 33 ft. square, then 1 ft. 6 in. 



high ; total height of brickwork 

 Concrete 80 ft. 6 in. square 



Total height, including foundation, 



The foundation rests upon a firm bed of gravel 12 feet below the 

 foot paving of Charing Cross, or 16 feet 6 inches below the level of 

 Trafalgar Square. 



Surrounding the base of the column there is to be a landing 10 feet 

 6 inches wide, and 10 steps 80 feet square at the bottom, in all 7 feet 

 high above the level of the paving in Trafalgar Square, m, iking tlje 

 total height of the column above this level 152 feet G inches, and in- 

 cluding the figure 171 feet. 



The height of Pompey's Pillar is 90ft; Trajan's Pillar, 115 ft. . 

 The Monument of London, 202 ft.; The York Column, 138 ft. ; The 

 Nelson Monument at Dublin, 134 ft., and at Yarmouth, 140 ft.; Na- 

 poleon Column at Paris, 132 ft.; July Column, 157 ft. ; and the Alex- 

 ander Column at St. Petersburg!), 175 ft. 6 in. 



