6 ANNUAL OF SCIENTIFIC DISCOVERY. 



were used for expedition, each of which accommodated two glaziers, 

 and travelled on wheels in the gutters, as in railway trams, and spanned 

 a width, or one ridge and two sloping sides, of the roof. The workmen 

 sat at the end of the platform, which they moved backward by a winch, 

 as they inserted a pane of glass before them ; and thus they travelled 

 throughout the nave roof, their supplies of sash-bars, glass, putty, &c., 

 being", from time to time, hoisted through an opening in the stage of 

 the wagon. In bad weather, the workmen were protected by a sort of 

 tilt of canvas upon hoops. By aid of these wagons, eighty men, in six 

 days, put in upwards of 18,000 panes, or 62, GOO feet superficial, of glass. 

 The greatest number of frames inserted by a man in one day was 108 , 

 being 367 feet 6 inches of glazing. 



The thickness of the glass was important, but the width was equally 

 so. Thus, if a piece of glass of a certain thickness and width be broken 

 by hailstones, reduce the width, and it will bear then- force. Now, the 

 panes used in the building are 49 inches long, and 10 in width. If, 

 instead of 10-inch width, it had been 15, the glass, it is calculated, 

 would have been broken in the first hail-storm. 



In order to facilitate the great amount of labor that would be re- 

 quired in making the sash-bars, a machine was invented by Mr. Paxton, 

 which accomplished the work with great rapidity. Its peculiar working 

 feature was, that the bar was presented to the saws below the centre 

 of motion, instead of above it, (as is usual,) and to the sides of the saw 

 which were ascending from the table, instead of those which were de- 

 scending ; this arrangement being necessary to suit the direction of the 

 teeth to the grain of the wood. It was essential that the machine re- 

 volve 1200 in a minute, to finish the work in a proper manner. 



The gutters employed in this building, from then* designer, have been 

 termed the " Paxton gutters." It has also been termed a three-way 

 gutter, from its having in its upper surface a semi-circular groove, to re- 

 ceive the water from the external glass roof, which springs from it 

 on both sides ; and from its having also, on each of the two vertical 

 sides, lower down, an oblique groove to receive the condensed vapors 

 from the inner surface of the glass ; the ends of these gutters being 

 connected by oblique cuts with the box-gutters. The Paxton gutter is 

 of the bell-shape inverted, from that form expanding upwards, and 

 therefore being less liable than any other to become obstructed. The 

 gutter is cut in lengths of 24 feet, which would bend or " sag," were 

 they not trussed by rods of iron fixed beneath the gutter, secured to its 

 two ends by cast-iron shoes, and pressed up by cast-iron standards at 

 eight feet intervals, with a rise of 2A inches in the entire length ; thus 

 trussed, the gutter will support 1 tons weight. Similar gutters were 

 employed by Mr. Paxton in the Chatsworth Conservatory in 1837 ; they 

 were then made by hand, but machinery has since been employed in 

 their construction. 



The details of the transept correspond with the other parts of the 

 building, so far as columns, girders and galleries are concerned. At 

 the level of the flat roof the main difference commences by the spring- 

 ing of the lofty and semi-circular roof, the two end faces of which are 

 handsomely distinguished by their radiating frame- work. The transept 



