CUTTERS OF MR. PAXTON'S SASH-BAR MACHINE.
"For this apparatus the Society of Arts, in April, 1841, awarded me a medal; and this machine is the type from which all the sash-bar machines found in use throughout the country at the present time are taken. As the Conservatory was erected under my own immediate superintendence, I am able to speak accurately as to the advantages of the machine: it has, in regard to that building alone, saved in expenses 1,400l. The length of each of the bars of the Conservatory is 48 inches; only one inch shorter than those of the Exhibition Building. The machine was first used in its present form in August, 1838; and its original cost, including table, wheels, and everything complete, was 20l. The motive power is from a steam-engine employed on the premises for other purposes; and any well-seasoned timber may be used. The attendants required are only a man and a boy, and the expense of the power required for it when in use is comparatively trifling. The sash-bars may be made of any form, by changing the character of the saws.
"There is one particular feature in working the machine, namely, the bar is presented to the saws below the centre of motion, instead of above it (as is usual); and to the sides of the saw which are ascending from the table, instead of those which are descending. These arrangements were necessary to suit the direction of the teeth to the grain of the wood; for when the bars were presented to the saws in the usual way, the wood was crushed instead of being cut and cleaned. It is essential that the machine should revolve 1,200 times in a minute to finish the work in a proper manner.
"The glass and glazing of the Chatsworth Conservatory caused me considerable thought and anxiety, as I was very desirous to do away altogether with the numerous overlaps connected with the old system of glazing with short lengths. This old method, even under the best of management, is certain, in the course of a few years, to render unsightly any structure, however well built.
"In the course of my inquiries, I heard that Messrs. Chance and Co., of Birmingham, had just introduced from the Continent the manufacture of sheet glass. Accordingly, I went to see them make this new article, and found they were able to manufacture it three feet in length. I was advised to use this glass in two lengths, with one overlap; but to this I could not assent, as I observed, that since they had so far advanced as to be able to produce sheets three feet in length, I saw no reason why they could not accomplish another foot; and, if this could not be done, I would decline giving the order, as, at that time, sheet glass was altogether an experiment for horticultural purposes. These gentlemen, however, shortly afterwards informed me that they had one person who could make it the desired length, and, if I would give the order, they would furnish me with all I required.
"It may just be remarked here that the glass for the Exhibition Building is forty-nine inches long—a size which no country except England is able to furnish in any large quantity, even at the present day.
"In 1840 the Chatsworth Conservatory was completed and planted. The whole length of this building is 277 feet; its breadth, 123 feet over the walls; and the height, from the floor to the highest part, 67 feet.
"Notwithstanding the success which attended the erection of these buildings, it became to me a question of importance how far an extensive structure might be covered in with flat ridge-and-furrow roofs; that is, the ridge-and-valley rafters placed on a level, instead of at an inclination, as in the green-house, or curvilinear, as in the Great Conservatory. I therefore prepared some plans for an erection of the kind for the Earl of Burlington, somewhere about ten years ago; but, on account of the lamented death of the Countess, the design of erection was abandoned. However, from that time I felt assured, not only that it could be done satisfactorily, but that the most appropriate manner to form and support level glass roofs, to a great extent, was that adopted this year for the New Victoria House at Chatsworth, which may be considered a miniature type of the Great Industrial Building.
"Before describing this house, however, it may be well to notice two instances in which the flat roofs had been previously tried, and in both cases with the most perfect success.
"The first of these was a conservatory attached to a villa in Darley Dale, only a short distance from Chatsworth. This building is divided into five bays, with a glass door in the centre, and glass pilasters separating the bays; the ridge-and-furrow roof covers an opening of seventeen feet in the clear. The ventilation is simultaneously effected by a lever connected with a rod, which is attached to all the ventilators....