Merits and Demerits of Iron Hot-houses. 29 1 



Art. XV. On the Merits and Demerits of Iron Hot-houses 

 for the Cidture of the Pine Apple. By Mr. Alexander 

 Gordon, Gardener to Sir William Wake, Bart. Courteen 

 Hall, near Northampton. 



Dear Sir, 



Excepting a communication from the President of the 

 Horticultural Society, which was published in their Transac- 

 tions some time since, I am not aware of any opinion having 

 as yet been given on the merits or demerits of curvilinear hot- 

 houses, constructed of iron sash bar, for the cultivation of the 

 pine apple. In consequence of this deficiency on that point, 

 I make bold to offer a few observations on the subject, which, 

 if you think worthy of a place in the Gardener's Magazine, 

 they are freely offered. 



In the first place it is absolutely necessary, for bringing 

 pine apples to perfection, (under whatever structure or build- 

 ing they may be grown), to have a sufficient ventilation, that 

 the heated or confined air may be allowed to escape, and a 

 free admission of fresh air permitted to enter ; but this is more 

 particularly requisite under the curvilinear iron bar, as a much 

 larger portion of the sun's rays are obviously transmitted by 

 the additional surface of glass which it contains, than would 

 be the case in a house constructed of the common sash and 

 rafter. Particular attention to the regulation of the ventilators 

 is also a very requisite point in the management of a curvili- 

 near house, much more so than in a common pit or stove. 



One apparent bad effect, I am well aware, will result from 

 the adoption of the iron bar, viz. the plants soon assume a 

 rusty tinge and unhealthy appearance during the summer 

 months ; but in the autumn they regain that green hue which 

 is so sure an emblem of health in the pine. These transitions 

 I at first considered to be of a decidedly injurious nature, but 

 experience proved that in the swelling off and flavour of fruit, 

 it did not materially injure them ; however, I certainly would 

 prefer retaining the green hue. In the summers of 1825-6, 1 

 succeeded far beyond my most sanguine expectations in accom- 

 plishing this desired object ; namely, by shading with sheets 

 of canvass, from the hours of nine, ten, and eleven in the 

 morning, until three, four, and five in the afternoon, accord- 

 ing to the influence of the sun. In addition to the shading, 

 I kept a constant saturated atmosphere in the interior of the 

 house, from which the greatest benefits were derived in the 

 swelling of the fruit, and also in destroying the red spider. 

 Every practical gardener is aware how difficult it is to subdue 



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