CONSTRUCTION OF THE BUILDING.

73

plane of this saw. In the centre of this frame a species of chair was constructed,capable of turning round, and a shoe was fixed at the extremity of the frame farthestfrom the saw. The end of a gutter about 24 feet long was thrust into this shoe,and its middle supported by the chair already mentioned. The end nearest tothe saw was then pressed down, and secured by an iron strap. Thus retained inposition, it was necessarily bent to precisely that camber arranged to be ultimatelygiven to it by suspension-rods and struts. The circular saw, revolving rapidly,was then made to descend until its edge came in contact with the end of thegutter, which it cut to the precise length required, and at exactly the rightangle. The axis of the circular saw Fig 23

was then still further lowered down,until the gouges fixed on its side cuttheir way through the gutter, makinga semicircular groove through itsdepth. One end being thus scoopedout, the gutter was released from itsposition, turned round, and securedin a contrary direction in the shoeat the opposite extremity of the sup-porting frame. The other end of thegutter, thus presented in its turn tothe saw, was then subjected to asimilar process, after which it wasremoved, perfectly ready for the at-tachment of its iron bowstring.

A machine of somewhat similar a p The ridges,

construction (though much simpler)to that by which the Paxton gutterswere made, brought the ridges to their proper form.

In the course of numerous experiments which Mr. PAXTON had commenced as The sash-bars—early as the year 1828, the great necessity for providing some machine by which improvements ina quantity of sash-bars might be speedily and economically cut, was forciblyimpressed upon his mind. In the Paper we have already quoted, Mr. Paxton thusdescribes the origin of machines of this description:—“In 1837 the foundations“ of the great Conservatory (at Chatsworth) 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 of London, Manchester, and Birmingham , to see if any-“ thing had been invented that would afford the facilities I required. The only“ apparatus met with was a grooving-machine, which I ha'd at once connected with“ a steam-engine at Chatsworth, and which was subsequently so improved as to“make the sash-bar complete. For this apparatus the Society of Arts, in April1841, awarded me a medal; and this machine is the type from which all thesash-bar machines found in use throughout the country to the present time aretaken. As the Conservatory was erected under my own immediate superin-tendence, I am able to speak accurately as to the advantages of the machine.

“ It has, in regard to that building alone, saved in expenses 1,4007. The length of“ each of the bais of the Conservatory is 48 inches, only one inch shorter than those