540 



DETAILS OF CONSTRUCTION. 



torn of the lights, instead of dropping on 

 the surface of the bed." The grooves, it 

 will be observed, are upon Read's prin- 

 ciple, but not so well contrived for the 

 insertion of the glass, as they are all of 

 the same depth. 



Curtis and Harrisons mode. — Fig. 761 

 shows the principle. The frame of the 



Fig. 761. 



sash is constructed 

 in the usual man- 

 ner, and rebated 

 on the inside all 

 round, for the re- 

 ception of ^he 

 glass j the astragals 

 or bars are flat on 

 their upper sides, 

 and exactly level 

 with the rebate in 

 the frame. The 

 glass is cut into 

 squares and laid on 

 the bars upon a 

 very thin coat of 

 putty, and fastened down by means of a 

 metallic screw and flat collar, which are 

 placed at each angle — the lower side of 

 the collar holding the glass in its place. 

 The advantages of this mode appears to 

 consist in presenting a plain surface of 

 glass over the whole roof — thus saving 

 the expense of repairing, putty, painting, 

 and securing the durability of the astra- 

 gals, which are covered with the glass. 

 The objections to it are the difficulty of 

 removing the screws in case of repairs, 

 and the trouble in cutting the glass to 

 the exact size required. 



Saul's method is intended to protect 

 the rafters and sash-bars 

 from exposure to the wea- 

 ther, and to give the outside 

 of the roof a smooth and 

 even appearance. Fig. 762 

 is a section of the rafter. 

 a b is a thin piece of metal, 

 lead or zinc, which runs be- 

 tween every joint of the 

 sash-bar, with the upper 

 part divided as shown, so as to 

 turn over each joint about a 

 quarter of an inch. The glass 

 is bedded on putty on the 

 top of the sash-bars ; and a 

 little white lead is put under 

 a b ; and when turned down it is com- 

 pletely waterproof. 



Barratfs method.- -The glass here is 

 laid upon a wooden sash-bar, (not in 

 rebates,) and the joints are covered where 

 the sides of the glass meet, with strips of 

 thin lead, so that the roof appears at a 

 distance to be one sheet of glass, and has 

 been found to be completely water-tight. 



Glazing with leaden laps was formerly 

 more practised than at present, although 

 instances occur of this being, under vari- 

 ous modifications, still met with. In the 

 Royal Gardens at Frogmore, where the 

 houses are glazed with panes from 24 

 to 30 inches in length, and cut curvilinear 

 at the ends, a very ingeniously contrived 

 leaden lap is employed, with a view to 

 render the roofs dry, and to exclude the 

 air by a more permanent material than 

 putty. In fig. 763, a, a lap, is shown as 



Fig. 763. 



Fig. 762. 



inserted in a groove ; b an improved lap, 

 and consists in using thin slips of lead in 

 connection with putty ; c Stewart's lap ; 

 d slip of thin lead bent in form of the 

 letter S, used by glaziers to keep the 

 glass in its proper place on steep roofs or 

 perpendicular frames until the putty is 

 thoroughly set, when they are entirely 

 removed. Metallic laps add greatly to 

 the strength of glazing by giving each 

 pane a firm bearing on the upper and 

 lower edges, and by preventing water 

 from lodging between the laps of the 

 glass ; and has the advantage over putty 

 that it cannot be displaced. The most 

 common forms of glazing are shown in 

 fig. 7 64 — namely, the rectangular, a ; the 

 fragment, b ; the perforated shield, c ; the 

 entire shield, d ; the rhomboidal, e ; the 

 curvilinear / ; the reversed curvilinear g ; 

 and the long pane of from 12 inches to 

 3 or 4 feet, introduced since the repeal 

 of the glass duty. Of all these methods, 

 we greatly prefer the curvilinear, be- 

 cause the rain water is in it attracted 

 to the middle of the panes, and conse- 

 quently drawn from the sides, where it 

 might find its way under the putty, and 

 thence into the house ; and if a small 

 opening be left in the putty at the centre 



