226 A BOOK ABOUT THE GARDEN. 



intervening, there is an orchid house of the same 

 length, ten feet wide, in two compartments, contain- 

 ing a choice collection of these lovely luxuries, 

 which are beyond my exchequer and experience, and 

 of which I only remember Odontoglossum Alexandras, 

 and amid countless beautiful Cypripediums, hirsutum, 

 Lowi, and niveum. On the north side of the orchid 

 house there is (3) a row of frames for striking, to 

 which heat may be given "at pleasure. The entire 

 cost was 160, and the consumption of fuel is about 

 nine tons of culm (at 14s. per ton) per annum. 



But I have made special mention of this range of 

 houses, of which the reader who possesses The Journal 

 of the Royal Horticultural Society will find a full 

 account illustrated in vol. vii., part i., because, 

 though the heating is admirable, the chief source 

 of its complete success is the constant supply of 

 fresh air. Canon Phillpotts maintains and proves 

 that the most perfect system of heating will fail 

 without good ventilation day and night, and that the 

 air of plant houses should be in direct proportion to 

 the light, the moisture, and the heat. At the same 

 time, care must be taken that the temperature is not 

 lowered too much or too suddenly by the admission 

 of external air, while, on the other hand, it must not 

 be dried by artificial heat. To obviate this difficulty 

 there is an air chamber between the two buildings, 

 from which several small drains open into the pits, 

 &c., six inches above the floor, with gratings about 

 six inches square of perforated zinc. From these a 

 constant supply of fresh air in small and broken 

 quantities arrives, so that there is no strong draught, 



