CONSERVATORIES. 



383 



supported upon columns, walls, &c. Its 

 only force would be in an oblique or pen- 

 dulous direction upon the surface of the 

 roof — but that roof could be so tied to- 

 gether externally by tension-rods, that 

 the force of the wind would meet with 

 resistance from them from whatever point 

 it might blow ; and when we consider 

 that an inch bar of best iron is capable of 

 sustaining a weight, when suspended, of 

 nearly 30 tons, we need not fear the force 

 of the wind upon a ridge-and-furrow roof, 

 be its extent ever so great. 



Fig. 515 shows part of the elevation of 

 such a structure, the front or perpen- 

 dicular lights being made to open by 

 running past each other, as elsewhere 

 explained. Cast-iron tubular columns, 



10 inches in diameter, are planted in a 

 Fig. 515. 



sufficient bed of concrete to enable them 



to resist the strain of the tension-rods, 

 which are fixed to their upper end, as 

 seen in fig. 516, a a. These columns 

 may be architectural or not, according to 

 taste, and may be finished at top with 

 any appropriate ornament. Both sides 

 of the structure are the same, and the 

 columns are carried up opposite the val- 

 leys, to give the necessary fulcrum to the 

 suspension-rods. Fig. 517 is a section of 

 the gutters, while fig. 516 is that of the 

 longitudinal line. The following descrip- 

 tion will more clearly explain the con- 

 struction : — The gutter, as above, is formed 

 of malleable iron boiler-plates a quarter of 

 an inch thick, having a sole, of malleable 

 iron rolled to the shape shown. To this 

 bottom plate the sides are joined by rivets 

 f-inch diameter, and 3 inches apart, as 

 shown by the dotted line in longitudinal 

 section. In the upper edge of the gutter 

 are fixed by f rivets, 4 inches apart, two 

 pieces of angle iron, e b, made to suit any 

 angle which the roof may require. This 

 gutter is made all in one length, and 



divided into five equal distances, n m p r, 

 on fig. 516. At each of these divisions is 

 fixed a strap d, 3 inches broad, f thick, 



