"In 1837 the foundations of the Great Conservatory were commenced; and in constructing so great a building it was found desirable to contrive some means for abridging the great amount of manual labour that would be required in making the immense number of sash-bars requisite for the purpose. Accordingly, I visited all the great workshops in London, Manchester, and Birmingham, to see if anything had been invented that would afford the facilities I required. The only apparatus met with was a grooving-machine, which I had at once connected with a steam-engine at Chatsworth, and which was subsequently so improved as to make the sash-bar complete. [Illustration: 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 1,400_l._ 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 20_l._ 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.