THE FORCING GARDEN". 



523 



Cast-iron is not so liable to rust as the last, neither is it so 

 materially affected by expansion, as to cause any considerable 

 breakincc of glass, but then sashes of cast iron are less calcu- 



o to ' 



lated to bear any degree of pressure, and are liable, in con- 

 sequence of their extreme brittleness, to break off short upon 

 any sudden blow, or pressure being put upon them suddenly ; 

 and above all, when once they are broken, they are not rea- 

 dily repaired without being recast, and the time lost, and the 

 expense of the repairs, form surely a heavy balance against 

 them. They cannot either be constructed on so slight a prin- 

 ciple as houses of the mixed metals, or of wrought iron, and 

 consequently are so heavy, that they will, in the end, hasten 

 their own decay. Their weight on steep roofs is not easily sup- 

 ported ; and when the ropes by which they are let up and down, 

 in the process of giving air, break, which is no uncommon 

 circumstance, their ponderous weight in falling shakes the 

 whole fabric, and the fragments of some twenty or thirty 

 squares of glass, bear evidence of the extent of the disaster. 

 This we have frequently experienced, and it must be admitted 

 that such accidents occur also in wooden houses, but the con- 

 cussion is not so great, and the effect produced is seldom to 

 any extent injurious. 



That metallic houses, from a variety of causes, break more 

 glass than wooden ones is evident. The light which supplies 

 that herculean undertaking, the Colosseum, in the Regent's 

 Park, is admitted by two immense sky-lights of metallic con- 

 struction : during the few extremely hot days of the summer of 

 1827, some hundred squares of glass v/ere daily broken by 

 expansion ; of this fact the ingenious and able projector is 

 perfectly sensible, and being convinced, not only of the pre- 

 vailing fault, but n\so of the attendant expense and inutility, 

 has used nothing but wood in the erection of a range of con- 

 servatories, green-houses, and stoves, upon a scale and plan 

 entirely unprecedented in this country. The public will soon 

 be satisfied that houses can be constructed as elegantly and 

 lightly, and at a much less expense, of wood, than of any me- 

 tallic matter whatever. There are few of the numerous visitors, 

 who have seen them, that have not supposed them to be iron, 

 until informed of the contrary. 



