STRUCTURES ADAPTED TO PARTICULAR PURPOSES. 81 



beauty, even of the plainest kind of structures, may be easily 

 heightened and increased by an ornamental moulding of wood 

 along the ridge of the roof, if a span, or on the end rafters and 

 front plate, as in Figs. 26 and 27, which will deprive the house 

 of none of its lightness, and will give it a neater and more ele- 

 gant appearance. 



Plants placed at a distance, either under water or under glass, 

 arc as much influenced in their development by the light as by 

 the heat. When plants are a great distance from the roof, they 

 are, of course, in a colder and denser medium at the surface of 

 the soil than at the top of the house, and there cannot be a 

 doubt that this difference in the density and temperature of the 

 atmosphere has much to do with the struggle and effort which 

 every plant makes to rise upward, and to elevate its assimilating 

 organs into the warmer and most humid regions of the house. 

 It will also be found that the difference betwixt the higher and 

 lower strata of air in hot-houses, is more immediately the cause 

 of plants drawing, and becoming weak, than anything that re- 

 sults from a feeble constitution, or from a deficiency of atmos- 

 pheric air. 



Notwithstanding the practical illustrations of this prevailing 

 error in plant-houses, there seems to have been very little done 

 to counteract this fault in lofty houses. The large conservatory 

 in the Regent's Park, Botanic Garden, is the only structure of 

 great size where this circumstance has had sufficient weight to 

 induce the erectors to provide against it, in the general design 

 and construction of the building. This admirable plant-house 

 stands as a striking illustration of what can be done on a grand 

 scale, without rendering fitness for the end in view subservient 

 to architectural display, and yet, without depriving the structure 

 of that dignity and effect which fine conservatories always convey 

 to the cultivated mind. This conservatory, we believe,' is the 

 result of well digested practical and scientific knowledge, and 

 we doubt if there be any other such erection in England, where 

 the effect of this rare combination is so strikingly displayed on 

 a scale so magnificent; and the result of this combination has 

 indeed been clearly manifested, in the formation and subsequent 

 management of this beautiful garden. 



