SECTION II. 



DESIGN. 



1. General Principles. — To ascertain principles of action, 

 it is always necessary to begin by considering the end in view. 

 The object or end of hot-houses is to form habitations for vege- 

 tables, and either for such exotic plants as will not grow in ths 

 open air of the country where the structure is to be erected, or 

 for such indigenous or acclimated plants as it is desired to force 

 or excite into a state of vegetation, or accelerate in their pro- 

 gress to maturity, at extraordinary seasons. The former class 

 of structures are generally denominated green-houses, or botanic 

 stoves, in which the object is to imitate the native clime and 

 soil of the plants cultivated ; the latter, comprehending forcing- 

 houses and culinary stoves, in which the object is to form an 

 exciting climate and soil on general principles, and to imitate 

 particular climates. 



The chief agents of vegetable growth in their natural habita- 

 tions are light, heat, air, soil, and moisture ; and the merit of 

 managing these structures, and the success of cultivating vege- 

 tables in them, depend on the perfection with which nature in 

 these respects is imitated. 



To carry out the imitation to perfection, or anything like an 

 approach to it, it is absolutely necessary, as we have previously 

 observed, to be acquainted with the nature and habits of the 

 plants under cultivation. Vegetable physiology ought to form a 

 part of the acquirements of the hot-house architect ; and the 

 chief cause of the great improvement in these structures, of late 

 years, in England, is traceable to the fact, that their erection is 

 no longer left, as formerly, under the control of mansion archi- 

 tects, as they are at the present day throughout the length and 



