298 



FLOWER GARDEN. 



stages of plant-houses. The interior air is warmed hy one 

 or two flues, or other heating apparatus, according to its 

 volume. If a temperature of 45° Fahr. be maintained 

 during winter, it is sufficient. Sometimes green-houses 

 are constructed with span-roofs and a double stage; but 

 they have a very plain appearance, especially those which 

 are commonly erected in nursery gardens. They might 

 be made much more ornamental, with little loss of light, 

 as in the accompanying figure (Fig. 18), which is design- 

 ed for the south end of one of these span-roofed houses. 



Fi- 18. 



The plants have thus an east and west aspect, or enjoy 

 the morning and afternoon sun. Such houses may in- 



