SHADING OF ORCHID HOUSES. 53 



Vandas, Dendrohiums, and many others — such as we seldom see equalled now. 

 Since then we have used thinner shadings, with the best results. Our Vandas 

 thus treated have always been strong and healthy, with broader foliage, 

 producing their flower-spikes as often as three times a year, with the flowers of 

 a good colour, lasting a long time in perfection ; in fact we are never without 

 flowers, always having a good display. We refer more particularly to the 

 siMivis and tricolor section of the genus. Some people imagine Vandas do not 

 flower till they attain a large size, but such is not the case if they are properly 

 grown and thin shadiiig is used. 



" Our experience leads us to the belief that all Orchids, with a few exceptions, 

 require a thin shading, that is to say, one that, while warding ofE the direct 

 rays of the sun, will allow the light to enter through it. To arrive at this 

 result we now use a strong durable cotton netting, woven in small squares, 

 close enough to exclude the rays of the sun while the light penetrates it with 

 but little interruption. This netting stands exposure to the weather much 

 longer than canvas, and on that account is cheaper in the long run. Wo have- 

 used this material for some years in the case of cool Orchids, Mexican and 

 East Indian kinds, with the best results, the netting being attached to rollers- 

 with appropriate gear. For the cool Orchid houses we employ Eaised Blinds. 

 In the winter we take them off the house and put them in a place of safety 

 until they are required again in the ensuing spring.'' 



The Raised Blinds just referred to formed the subject of a subsequent 

 note under Plate 35 of the same work, which note is here transcribed : — 



" During the summer months we have found Eaised Blinds very beneficial 

 to the growth of Orchids, especially to those requiring cool-house culture. 

 When the hot summer's sun is shining upon the glass, it is very difficult, where 

 Raised Blinds are not employed, to keep the temperature sufficiently low. The 

 glass roof of the structure upon which the sun is shining becomes very hot, 

 even when shaded with ordinary blinds; but if Raised Blinds are used a 

 current of air is allowed to pass over the entire surface of the roof, and the 

 glass is kept comparatively cool. The effect of this is to decrease very appre- 

 ciably the internal temperature of the house ; and the moisture, which would 

 otherwise be dried up by the burning heat of the sun, produces a nice huniid 

 genial atmosphere in which Orchids delight. 



" We will now explain briefly the mode of construction. Supposing that the 

 house to be furnished with Raised Blinds is an ordinary span-roof structure, it 

 is necessary in the flrst place to provide a second ridge elevated about, six 

 inches above the top of the existing one. This should not consist of a solid 

 plank, but of a strip of timber sufficiently strong to bear the weight and strain of 

 the blinds and roller ; and should be supported on blocks of wood placed at 

 intervals in order to allow the current of air from below to find an outlet, 

 which would not be the ca,se if a solid ridge-board were adopted. Having 

 arranged for the ridge, the next thing is to provide supports for the rollers. 

 Either wood or iron may be used for this purpose, but we have found iron to be 

 the lightest looking and the most durable. Where the length of the rafters 

 does not exceed say eight feet, half-inch rod iron will be found to be strong 

 enough, and this should be cut into proper lengths with the lower end turned 

 up in a semi-oircular form so as to catch the roller when it descends, and 



