10 OENAMBNTAL FOLUGB PLANTS. 



in this place for a span-roof, the length of course being 

 altered to suit circumstances, and ia this case the lan- 

 tern system of ventilation or the ordinary sliding sash, 

 may be adopted. 



GREENHOUSES AND CONSERVATORIES. 



HERE are, however, a quantity of plants whicb 

 come from tropical countries, yet, as they are 

 found growing at considerable elevations, only 

 require protection from frost and pierciug winds, and 

 we here give a transverse section and ground plan of 

 a house suited for the cultivation of plants from such 

 countries as the Cape of Good Hope, New Holland, New 

 Zealand, Chili, or, iudeed, from most of the temperate 

 regions of the globe. The dimensions and general features 

 are the same as in the structure recommended for stove 

 plants, but with this difference — that in the greenhouse 

 the side lights are all made to open, and the lantern is 

 not used, but the upper sashes of the roof slide up and 

 down in the ordinary way. The underground system of 

 ventilation should be applied to this structure as well 

 as to the stove, as it affords means of maintaining a 

 pure and healthy atmosphere in the interior, without in- 

 jury to the plants, even in the most severe weather. 

 Fresh air is most essential to the well-being of green- 

 house plants, but cold draughts must be avoided, for 

 nothing is more injurious to plants of any kind. Indeed, 

 such often result in their speedy death, therefore care- 

 fully attend to this in giving air to plant houses. 



In heating such a structure as that we have here- 

 recommended, two rows of pipes for hot water will be 



