12 THE aMATETJe's GREENHOUSE 



of the former as to protective power and duration, but in 

 favour of the latter as to lowness of first cost. As to rafters, 

 those of wood are more perishable than iron, and admit less light. 

 On the other hand, wood is a non-conducting substance, and if 

 a nice comparison were made it would be found that a house 

 with a light iron roof would cost rather more for fuel than a 

 house of the same shape and dimensions with wood rafters, to 

 maintain an equal temperature throughout the winter. But 

 light is life, and iron roofs are adapted to catch the utmost 

 glimmer of the weak daylight of this cloudy clime, and in the 

 case of a structure intended for succulent plants, and such 

 other subjects as need the fullest possible flood of light, iron 

 is certainly to be preferred. In the case of a large conserva- 

 tory iron is unquestionably superior to wood, and the more 

 so with every advance in elegance of construction. 



PAEANEPHELIUS UNIFIOKXJS. 



