VENTILATION OF ORCHID HOUSES. 65 



being able to give what are to them satisfactory reasons why 

 the particular form they adopt is the best. That we have this 

 diversity amongst boilers is no doubt a great advantage, for 

 one that may work admirably in one place, may not, through 

 some peculiarity of place or position, be so thoroughly satis- 

 factory in another. Moreover, the fuel most readily available 

 in one place, and which may suit one class of boiler, may not 

 be so readily obtained in another place, and therefore those 

 who are so situated will naturally have recourse to a boiler 

 adapted to consume the fuel which they can obtain for heating 

 it. When a good draught can be obtained we have found 

 anthracite coal the best fuel for most kinds of boilers ; it is 

 more lasting than coke, is smokeless, and gives out twice as 

 much heat, and is altogether a cheaper and much better 

 article, although more costly in the first outlay. 



VENTILATION OF OKCHID HOUSES. 



HIS is of itself of great importance, but the manner 

 in which it is carried out is equally if not more 

 important ; for if cold chilly air is allowed to pass 

 among the plants they will not thrive, and all the care which 

 has otherwise been bestovt^ed on them will be in vain. 

 The means of ventilation should be provided by ventilators 

 fixed near the ground, close to the hot-water pipes, in order 

 that the air may be warmed as it enters the house, and before 

 it reaches the plants. Fresh air should also be admitted by 

 underground pipes, so that in cold weather a current of pure 

 air may be maintained. This can be accomplished by laying 

 drain-pipes from the outside under the foundation to the in- 

 side under the hot-water pipes, so that the air is warmed 



