264 ON CURVILINEAR IRON ROOFS TO HOTHOUSES. 



The curvilinear iron roof certainly transmits heat more rapidly than 

 one of wood of the ordinary construction, but not to any considerable 

 extent, I think, more rapidly than a roof composed of wood and glass 

 would do, if the wood were employed in as small quantities as the iron is, 

 and not nearly to as great an extent as a roof composed wholly of glass 

 would do, if such could be constructed. 



My house is fifty feet long, and ten feet wide, and it is heated by a 

 single fire of moderate size; and I have found that single fire fully 

 sufficient to keep pine-apple plants in a healthy growing state, in all 

 seasons of the year, without the aid of bark or hot-bed of any kind, and 

 without the protection of any kind of covering *. I have always used it 

 as a fruiting-house, and my plants, after being placed in it, have grown 

 admirably, and have shown fruit well ; but the fruit has never till the 

 present year, except in one instance, when the plants stood close to the 

 door, swelled properly. Its taste and flavour have nevertheless been 

 good, and it constantly ripened in a singularly short time. 



The fruit which appeared in September and October, in the last 

 autumn, became ripe in January, and whenever one fruit became ripe, its 

 aroma appeared to accelerate the maturity of all in its vicinity. 



The queen pine-apples were generally very similar to those I have 

 usually seen at the shops in London in the months of April and May ; 

 and with imperfections arising, I believe, from the same source, the want 

 of efficient ventilation. 



In houses of ordinary construction, with roofs of sliding lights, air 

 enters and escapes at all times with much rapidity ; and the consequent 

 change of air is very/nearly, if not wholly, sufficient to enable the pine- 

 apple to acquire maturity and perfection at all seasons ; provided the 

 flues operate with sufficient power to give the requisite temperature. 

 But in my house, with a curvilinear roof, I acquired the power of almost 

 wholly preventing any change of air whatever ; and I exercised that power 

 too extensively, after the fruit was shown, and particularly after a part 

 of it had nearly acquired maturity. In the last spring I adopted a mode 

 of ventilation, from which I expected to derive all the advantages of 

 change of air, without materially lowering the temperature of the house ; 

 and the success of it has greatly exceeded the expectations I had enter- 

 tained. I shall best be able to show the advantages of this mode of 



* A much higher temperature than my machinery enables me to give, and varying from 75 

 to 90 in winter, and from 80 to 105 in summer, would, however, be highly beneficial : and I 

 feel quite confident that in a dry stove of such temperature pine-apples might, under appro- 

 priate management, be abundantly ripened, and in considerable perfection, in any part of the 

 year. 



