From the simplicity of the details of the construction, and their constant recurrence, it will be seen that so long as the ends of the building were left incomplete, its size could easily be limited or expanded, so as to include that precise amount of space which, up to the last moment when the point could be kept open, appeared most likely to be required. This simplicity of arrangement will also be found very advantageous in case the building is removed after the termination of its present temporary purpose; as the parts may be easily separated without much injury, and as readily re-erected, either as a whole, or even in many separate buildings, having the same arrangement of parts, without the same general form or appearance.

It has been calculated that the passages remaining in the building, after deducting the space appropriated to the objects exhibited, will hold more than 100,000 persons; though it is not to be expected that half that number will be collected there at one time. The ventilation and supply of fresh air for so vast a throng was therefore a matter of the first importance; and the means already described for accomplishing this great object are so ample, that any inconvenience from oppressive heat or foul air can hardly be expected. The canvass with which the roof is covered will not only serve to modify the heat of the sun in the interior, but it is expected that if it be watered by the hose of engines, it may even reduce the temperature within to considerably below that of the external air. From his experience in glass-houses for horticultural purposes, Mr. Paxton speaks confidently on this point.

The arrangement of the construction of the building resting on isolated instead of continuous supports, will enable all traces of it to be readily effaced from the site if it is removed; and, on the other hand, if it remains, it is evidently peculiarly suited to form a vast winter-garden and public promenade.

EFORE taking leave of the reader who may have patiently followed us thus far, a few words may be necessary on the general arrangement of the articles to be exhibited in the building whose outline and details we have been endeavouring to trace. The first classification is geographical. All the western half of the building is given to England, and the eastern, which is rather the larger of the two, to foreign countries; the space assigned to each country being distinctly defined, so as to avoid the possibility of any disputes. As far as it was possible, the space for each country is so arranged as to have a frontage towards the main central avenue, and in most cases occupies a strip the whole width of the building; the visitor, therefore, passing up and down the length, will not miss out any country.

In the central avenue, and immediately on either side of it, are placed the most remarkable specimens of objects coming under the class of fine-arts, or otherwise sufficiently remarkable to entitle them to such a prominent place. Behind these, in the side avenues, will be found the various specimens of manufactured articles; and along the outside longitudinal avenues are placed, on the south side, those belonging to the class of raw products (a portion being devoted to agricultural implements), and the projecting portion of the building on the north side forms the hall of machinery, which is separated by a partition of glazed sashes from the rest of the building. Many of the articles will be grouped in courts, an arrangement which the construction particularly leads to; and these will probably form some of the greatest attractions in the Exhibition, each being, as it were, complete in itself, and the inclosures preventing the eye from being distracted by distant objects. To enter further into the detail of this part of the subject would be foreign to the purpose of this work, the building itself being our text.

We have now, we believe, completed the pleasant task we proposed to ourselves at the outset, and we hope that in doing so we may have been able to render interesting to our general readers this description of operations, usually occupying the attention of the technical professions only. With this intention, we have avoided as far as possible the use of technical terms, which would be a dead letter to the uninitiated, at the risk, perhaps, of being considered inaccurate by those acquainted with all the details of the subject.

So many men whose eminent talent is well known and appreciated by the public have been engaged in perfecting the designs and carrying out the erection of this vast structure, that the critic should be one of no mean reputation who would venture to raise even a small voice of individual criticism on its merits. We have considered it, therefore, to be our part rather to record the opinions of others on any points where a discussion has been raised than to trouble the reader with any personal views, which would, perhaps, have only appeared impertinent.

The nature and extent of the difficulties which have been successfully surmounted in carrying out this great work can only be fully appreciated by those intimately acquainted with all its structural details and with its rapid progress; and its completion in so short a period must be regarded as a striking instance of the productive power and spirit of commercial enterprise of this country, while the fact of its being defrayed by the voluntary contributions of the people will illustrate in an interesting manner to our continental visitors that principle of self-government which forms the basis of all our institutions, and the spirit of private enterprise which characterises most of our great undertakings.