384 



PLANT-HOUSES. 



made to go round the sides and bottom 

 of the gutter. This strap, which is made 

 of L.M. iron, is pierced at the upper end 

 for the bolt to pass through. These gut- 

 ters are placed between two upright 

 columns a a, fig. 516, having a bracket 

 cast on them at o o for the gutter to rest 

 on, 6 feet from the top. The tops of these 

 pillars are cored out to allow the double 

 joints of the suspension-bars, 1 2 3 4, to be 

 inserted, a bolt of the best iron or soft 

 steel passing through the jaws of the cast- 

 iron pillars and joints of the suspension- 

 bars. These bars are l|-inch diameter, 

 of best iron, made with double joints on 

 both ends, as shown in section of gutter, 



the bolt / passing through the strap d 

 and the sides of the gutter, and also 

 through the double joints of the suspen- 

 sion-rods. The strap d is to support the 

 weight, and to prevent the sides of the 

 gutters from being torn out by the strain 

 of the suspension-rods. This gutter may 

 be made from 50 to 100 feet of span, and 

 requires transverse bars of round iron 

 crossing the gutter to keep it in a straight 

 line. The upright pillars may be made 

 of any pattern to suit the design of the 

 house, and should be, for an 80 feet span, 

 at least 8 inches diameter, and metal. 



Fig. 518 shows another mode of sus- 

 pending the gutters—for upon them the 



whole of the ridge-roof rests. Fig. 519, 

 section on A B, shows, upon an enlarged 



Fig. 519. 



scale, a section of the gutter and its con- 

 nection with the roof astragals a «, as 



well as an open passage, formed by a per- 

 forated plate of iron or open grating, to 

 prevent the snow from choking up the 

 gutter, and leaving a clear passage for 

 the melted snow-water passing off at b. 

 In fig. 520, the plan of the roof, are seen 

 the tension-rods connected with the gutter 

 stt a a a, while others are placed diagonally, 

 b b, from the upright columns, and 

 secured to the apex of the ridges, their 

 use being to tie the roof together, and 

 prevent vibration and pendulous motion. 

 The upright columns, gutters, tension, 

 and diagonals, are of iron, the ridges and 

 astragals of wood. Top ventilation is to 

 be effected by openings in the ridge, 

 which may, for this purpose, be in two 



