LIGHTS OR SASHES. 



545 



Fig. 770. 



proposes a gutter formed in the rafter as 

 at a a in the cut annexed, fig. 770. Many 

 other contrivances might 

 be shown, but these are 

 sufficient for our purpose ; 

 while we may take this 

 opportunity of stating 

 that condensed vapour, 

 if not in very great ex- 

 cess, is more useful than 

 baneful, -and also that, in 

 hothouses properly con- 

 structed and judiciously 

 managed, contrivances of 

 this kind can seldom be 

 wanted. Wherever they do appear, they 

 give us, as it were, to understand that 

 something is exceedingly defective in the 

 roof, and give the whole house a patchy 

 and unfinished appearance. 



§ 2. — LIGHTS OR SASHES. 



These are compartments of the roofs, 

 and often of the sides of hothouses, which 

 have hitherto been deemed indispensable 

 in hothouse-building. They are not now 

 so considered, fixed roofs having become 

 more common ; and we believe that, ere 

 long, excepting for pits and small houses 

 requiring to be annually uncovered, they 

 will be entirely disused. They consist of 

 two side pieces called styles, and two end 

 pieces, called the top and bottom rails, the 

 internal space being divided by rebated 

 bars called astragals, in the rebates of 

 which the glass is laid. Astragals are 

 also formed by having a groove cut out of 

 each side, into which the glass is let in 

 with a very small quantity of putty : the 

 one groove being cut deeper than the 

 other opposite to it, is to facilitate the 

 insertion of the glass. ( Vide Astragals 

 and Glazing.) The material employed 

 in their construction was for long wood ; 

 but, since the beginning of the present 

 century, cast and wrought iron, zinc and 

 copper, have been used. Cast-iron sashes 

 are too ponderous, and, when fractured, 

 are not easily repaired. Wrought-iron 

 ones are also liable to the first objection, 

 and, in addition, are subject to corro- 

 sion. Copper is less liable to these objec- 

 tions ; but its price must ever render it 

 rare in gardens, at least if the sashes are 

 entirely constructed of that metal. Zinc, 



VOL. I. 



although less expensive, is not well fitted 

 to the purpose. A combination of wood 

 and copper is perhaps at present the most 

 popular, the frame being of the former 

 and the astragals of the latter. Wrought- 

 iron frames and copper astragals are also 

 frequently used; those of the houses in 

 the Royal Garden at Frogmore are thus 

 constructed. 



Mr Crosskill, an extensive ironmaster 

 and hothouse-builder at Beverley, never 

 makes his sashes of iron, but of wood — 

 knowing from experience that wood is 

 lighter, and slides with greater ease, and 

 can be fitted more accurately to the raft- 

 ers, so as effectually to exclude the weather. 

 Another advantage arising from using 

 iron rafters and wooden sashes is, that the 

 former expand a little by the excessive 

 heat of summer, while from the same 

 cause the latter contract in a slight de- 

 gree, which prevents friction, and renders 

 the sashes more easily moved up and 

 down. 



§ 3. — RAFTERS AND ASTRAGALS. 



Rafters are constructed of wood, and of 

 cast and wrought iron. Astragals were 

 long formed of wood ; but of late years 

 they have been made sometimes of copper, 

 zinc, and cast and wrought iron also. As 

 may be supposed, there is a great variety 

 of these, both in regard to form and size. 



The annexed example of a 

 rafter, fig. 771, is to a scale 

 of 1 inch to 6, and has been 

 exemplified in the Royal 

 Gardens at Kew, in one of 

 the recent erections there. 

 We give it as an example of 

 one we do not by any means 

 approve of, on account of 

 the unnecessary mouldings, 

 which to us are no orna- 

 ment, and certainly lessen 

 the strength without diminishing the 

 substance. We have elsewhere stated 

 our objections to mouldings in hothouse 

 roofs : we consider them as so many re- 

 ceptacles for harbouring dirt and the 

 accumulation of damp. We know well, 

 from long experience, the difficulty of 

 getting joiners to abandon mouldings — 

 so pertinaciously do many of them ad- 

 here to " use and wont " habits. As an 



3 z 



Fig. 771. 



