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the level of the lead flat, and on the tops of those columns timbers were laid, forming landing stages or tram-ways, to receive the ribs when hoisted. It was of course necessary to raise the ribs sufficiently high above the lead flat to enable their ends to descend upon the tram-ways. To effect this it was determined that two ribs should be placed on end, at a distance of 24 feet from each other, and framed together with purlins and diagonal ties, exactly as they would have to be framed in their finished state. Two complete sets of additional temporary ties were further introduced, to provide for the strain to which the ribs would necessarily be exposed from their altered position in the act of hoisting. The feet of the ribs were securely attached to stout pieces of timber, to afford the means of safely attaching the cords by which they were to be raised. Thus framed together, the ribs were moved on rollers to the centre of the square formed by the intersection of the nave and transept.
On the extra strong trusses which have been described as spanning the nave Provisions for at this point, two pairs of shear-legs were fixed at 24 feet from one another, and secured by ropes connecting them with distant portions of the building. These hoisting shears consisted of two legs on each side of the transept, each leg being formed of three stout scaffold poles lashed together at the top, and footed on planks laid across the lead flat. The heads of these shear-legs inclining slightly forwards, had connected with them blocks and pulleys from which descended ropes, attached to the four ends of the two ribs. The hoisting ropes connected with the sets of pulleys passed down from the shears to leading blocks, attached to the four columns at the angles of the intersection of the nave and transept. From these guide blocks they were led off diagonally to four powerful crabs, so arranged that the gangs of men employed at each were placed opposite the end of the rib acted upon by the crab they worked; and thus the foreman of each gang was enabled so to regulate the exertions of his men as to make them correspond with those of the remaining gangs, and to maintain the two ends on each side in a perfectly horizontal plane.
As the diameter of the semicircular ribs exceeded the width of the transept by Raising. their own thickness, it became necessary, in order that they might pass between the trusses, to commence by raising two of their ends to a considerable height from the ground; and to maintain their diameter at the same angle of inclination until they were hoisted above the columns into which they had to drop. On raising them to a height of about 65 feet from the ground, the highest ends were drawn in a horizontal direction, so as to hang over a portion of the lead flats, and thus room was left to allow the other ends to be lifted to a corresponding height on the opposite side. The ribs were shifted slightly in a horizontal direction until the ends came over the columns, they were then lowered down upon rollers placed upon the tram-ways above mentioned, and by means of these rollers the ribs were moved along to the furthest end of the transept. The place in the centre of the building occupied by the ribs thus hoisted was immediately taken by another pair, which were similarly connected, raised, and moved to within 24 feet of the first pair.
When the whole of the ribs were thus elevated to their places, the spaces When raised, how between them were filled up with the necessary intermediate ribs and connections ; and thus the whole roof was framed together complete.
The raising of the main ribs commenced on the 4th of December, and the Time occupied in whole sixteen were fixed in one week. It occupied about an hour to raise a pair
and number of men required.
of ribs from the ground to the level of the lead flat, but the previous preparations involved a much longer space of time. Eleven men worked at each crab, and about 16 were employed on the lead flat, to guide the ribs in their ascent, and see to the safe condition of the shear-legs and tackle. Considering the anxious nature of this performance, it must be regarded as a most gratifying circumstance, that the whole operation was accomplished without any untoward
Glazing the nave roof.
Glazing the No sooner had the skeleton of the transept-roof been completed, than the work transept roof.
of glazing commenced. For a considerable portion of the height of the curve, ladders and temporary scaffolds enabled the workmen to proceed with their labours; but in order to complete the upper part an ingenious box was constructed, moving on wheels in the line of the gutters. This box was lowered down from the lead-flat at the summit to any portion of the roof.
The glazing of the nave roof presented formidable difficulties, from the great extent of work to be got through in so short a space of time. The ingenuity of the contractors was, however, brought to bear upon the subject, and provisions
were made by them for the simultaneous glazing of large areas, entirely indepenConstruction of dent of variations of weather. 76 machines were constructed, each capable of
accommodating two glaziers; these machines consisted of a stage of deal about 8 feet square, with an opening in its centre sufficiently large to admit of boxes of glass, and supplies of sash-bars, putty, &c., being hoisted through it. The stage rested on four small wheels, travelling in the Paxton gutters, and spanned a width consisting of one ridge and two sloping sides. In bad weather the workmen were covered by an awning of canvas, stretched over hoops for their protection.
In working, the men sat at the end of the platform next to whatever work had been last done; from which they pushed the stage backward sufficiently far to allow them to insert a pane of glass, and as soon as that was completed they moved again far enough to allow of the insertion of another. In this manner each stage travelled uninterruptedly from the transept to the east and west ends
of the building. The dexterity acquired by the men in working the machines Quantity of work was very remarkable. By means of them 80 men in one week put in upwards of
18,000 panes of glass, being not less than 62,600 feet superficial. The greatest number of panes inserted by a man in one day was 108, being 367 feet 6 inches of glazing. A somewhat similar machine has been constructed for the purpose of effecting any repairs that may be necessary in the finished roof, with the difference that its wheels travel upon the ridges instead of in the gutters, and that of course there is no aperture for the purpose of hoisting.
Taking into account the innumerable quantity of small castings requisite, and the extreme rapidity with which they had to be supplied, their quality and cleanness is truly remarkable; and the fact of their having all issued from one foundry, that of the contractors at Smethwiek, proves the great facility with which work
of that nature can be executed in England. Celerity with Among the later operations connected with the completion of the work, the
most remarkable for the celerity with which it was conducted, was the ornamental painting of the nave roof. Iron straps, attached to the trusses, supported a number of scaffold poles, on which a perfect cloud of boards was laid, and as many as between 400 and 500 painters, by these means, worked their way, with extreme rapidity, from one end of the building to the other.
Rapid supply of small castings.
which the painting of the nave roof was executed.
The magnitude of this great building elevated into serious undertakings matters The application which, under ordinary circumstances, are accounted little more than trifles. make the vallery Hence machinery was applied to the formation of the entire length of hand-rail required for the galleries. In fig. 33 is represented a set of cutters (A fig. 33), by exposure to the rapid revolution of which, roughly-shaped strips of mahogany were instantaneously converted into smooth and cleanly rounded hand-rails (B fig. 33). A little sand-paper and French-polish sufficed to bring them to their present excellent condition.
In summing up the description of any great engineering undertaking, it is too Paucity of often a painful task to have to record the loss of life so frequently involved. Considering the difficulties of construction, the necessary perils to which the workmen were exposed, and their habitual imprudence, arising, partly, from real indifference to danger, and partly from bravado, it has been a source of congratulation that, in the performance of this contract, but very few accidents have occurred, and those, with two or three exceptions, of a slight nature.
Having now brought to a close our description of the building as it exists, and Conclusion. of the processes by which its existence has been developed, it remains only to reiterate our conviction that the courage, energy, and strength represented by its construction should be regarded by every Englishman with emotions conducive to some yet higher manifestation of national capability; and at the same time to express a hope that the products of British industry (of which the building is but the shrine), may display, in a yet higher degree and in a yet more tangible and varied form, the sources of COMMERCIAL POWER, so many indications of which it has been our happy privilege to trace in the edifice itself.
M. DIGBY WYATT.
SCIENTIFIC REVISION AND PREPARATION OF
Exhibitors the authors.
Peculiar circum- The circumstances under which this work is published appear to call for some duction of Cata: observations upon the method of its production. From the fact that it is without
a precedent in the annals of literature, it follows that its preparation and publication have been attended with peculiar, because unforeseen, difficulties. All those obstacles in the way of its completion which would necessarily develop themselves from the remarkable manner in which its contents have been created, and from the want of a guiding experience in the publication of works of this nature, have been contended with in its progress to a perfect state. The following may be considered as an outline of the manner in which the materials for the construction of this volume were collected, and of the system adopted to reduce them to a definite form, and as far as possible to a certain degree of consistency of expression and of harmony of proportion.
It is not the least remarkable fact in connection with the Great Exhibition, that the Catalogue may be really regarded as the production of many thousands of authors, -represented by exhibitors themselves. By a decision of the Executive Committee, every exhibitor was required, prior to the reception of his articles at the Building, to have filled up a certain printed form, containing a description of his productions in the English language, accompanied with such general observations as might be suggested by the peculiar character of the things described and intended for exhibition. These forms, which were to be to the Catalogue what the MS. of an author is to his proposed work, were framed with care, and were accompanied with instructions for filling them up, which suggested those points on which interesting or important information might be supplied, together with the descriptive account. There were four varieties, each appropriated to one of the four great sections of Raw Materials, Machinery, Manufactures, and Fine Arts. The essential characters of these forms were similar in each section, but the instructions for filling them up differed necessarily with the peculiar differences suggested by each section. The subjoined form represents that used in sending in descriptions of machinery, and is a type of those used in the other sections :
List of Articles of MACHINERY to be exhibited by
Address, stating nearest Post Town.
Munifacturer, Designer, Incentor, or Proprietor.
In order to facilitate their classification on being returned by exhibitors, the Classification of forms in the four different sections were printed in black, blue, red, and yellow, the latter applying to sculpture and fine art, the former to raw materials, and the intermediate ones respectively to machinery and manufactures. Every exhibitor was required to send in one of these forms, accompanied with a duplicate in every respect similar to it, and in so doing was supplied with a “receipt for catalogue forms,” which was a guarantee for the reception of his goods into the Building. A very large number of these forms were printed and supplied to Local Committees, and to all exhibitors who applied for them. The instructions for filling them up were as follows:
RULES FOR COMPILING THE CATALOGUE. The Executive Committee are desirous of impressing upon Exhibitors that the formation of the ('atalogue which, however great may be its bulk, must necessarily be compiled and printed in a very short time, will be much facilitated, if Exhibitors will have the kindness to follow the rules hereinafter prescribed when they furnish the descriptions of the Articles as they wish them to appear in the Catalogue.
1. Every Exhibitor should write the description of every Article or series of Articles he Rules for comexhibits, on paper of the same size as the present page (namely, about 13 inches by 8 inches). piling forms for The paper must be written on one side only. There should be a margin of one inch at the left side of the page.
2. Should the description extend beyond a single page, each separate page must be marked with the Exhibitor's name, and numbered consecutively, both at the head and foot.
3. To prevent errors in compilation and misprinting, it is desirable the handwriting should be very clear, especial care being taken with all names and technical terms.
4. It is indispensable that each Exhibitor should furnish the following particulars, and in
Address, stating the nearest Post Town.
Capacity in which the Exhibitor appears, whether as Producer, Importer,
Manufacturer, Designer, Inventor, or Proprietor. IV. The name and description of every Article of importance or class of Articles exhibited ; each Article or Class beginning a separate paragraph, e.g.
a Specimens of dyed Cottons, &c.
b Specimens of dyed Silks, &c. 5. It is necessary that the descriptions of the Articles should set forth, as far as may be practicable, the following particulars :-As respects Articles to be exhibited
In SECTION 2. MACHINERY, the descriptions Raw Materials In SECTION 1. Raw MATERIALS and Pro
and Machinery. CESSES, the descriptions should specify
a The uses. a The commercial name in English, French, b The novelty, if any, in the invention. and German.
c Superiority of execution. b The scientific name.
d Increased efficiency or economy: c The place where obtained ; the name of e The importance of the Article in a social the mines and period they have been
or other point of view. worked, should be given with minerals. f The place where produced. d The place where exported.
9 Whether the Article is patented or not. e The uses.
h Where price is an element for consideraf The consumption.
tion, the price at which the producer 9 The superior excellence of the particular
can sell the Article. Specimens.
i Any particular features which the Exhih In the case of processes, such as dyes, or
bitor desires to be noticed by the Jury. prepared materials, such as mixed metals; it should be stated whether In SECTION 3. MANUFACTURES, the descriptions Manufactures. the Article is patented or not. The
should specify— novelty and importance of the prepared
a The uses.
d Impro forms or arrangements.
e Increased efficiency or economy. i Where price is an element for considera- f New use of known Materials.
tion, the price at which the importer g Use of new Materials.
h New combinations of Materials.
other point of view.