66 oechid-grow^e's manual. 



immediately upon entering the bouse by passing over tbe 

 beated pipes. In tbe bouses bere, tbere are three ventilators 

 on each side to each house in the brickwork opposite tbe 

 pipes. The ventilating shutters are made of wood, about two 

 feet long, and one foot wide ; sliding slate ventilators answer 

 perhaps better. There should be one glass ventilator at the 

 south end, near the joof, and one at the north end. We have 

 also four small ventilators near the ridge of tbe roof, two on 

 each side, on hinges, opening from the inside with cords ; 

 they are intended to let out the top-heat, the egress of which 

 we have found very essential to tbe well-being of the plants. 



Tbere are several contrivances for working the ventilators, 

 tbe most popular being by means of iron rods and levers run 

 from end to end of the bouse, so that all the ventilators may 

 be opened at once. Tbere are also many other appliances, but 

 great care is required in using them, so that in cold windy 

 weather too much air may not be given, as by all the ventila- 

 tors opening at once air is given simultaneously all over tbe 

 bouse, whereas it may only be expedient to give it at one end. 

 No rule can be laid down for ventilation, as so much depends 

 upon the locality where the plants are grown, and the period 

 of growth at which the plants have arrived, as well as on the 

 temperature of tbe house. 



SHADING OF ORCHID HOUSES. 



VERY Orchid house requires to be shaded, although 

 we are often told tbe practice is wrong ; but as 

 some plants would soon be destroyed if the burning 

 rays of the sun were allowed to shine upon them when grown 

 under glass, the use of blinds in summer is quite necessary 



