232 CULTIVATION. 



to grow to the height of thirty feet or more, and 

 to be proportionally wide. The frame and roof 

 should be as light as is consistent with its sta- 

 bility. The means for the admission of fresh air, 

 by moveable sashes and ventilators, must be par- 

 ticularly attended to in the construction. The 

 flues, whether for fire, steam, or hot water, 

 should be conducted under the paths, so as not 

 to disfigure or encumber the surface within the 

 building ; the paths being formed of wooden or 

 cast-iron gratings. The borders for the plants 

 should be made to the depth of three feet on a 

 dry subsoil; and composed of fresh light loam, 

 leaf-mould, and moor-earth, well intermixed. 

 Some of the tropical plants have thick fleshy 

 fibres, and seem to delight in a loose porous 

 soil ; though the palms require rather a tenacious 

 loam. These, and any other plant requiring a 

 peculiar kind of soil, may have it applied to 

 their roots when planted. The columns in the 

 interior of a conservatory are fine stations for 

 climbers ; such as passion-flowers, and the like. 

 All plants that are shrubby, and which flower 



