20 PROPAGATING HOUSES AND PITS. 



or perforated zinc is stretched to prevent draughts of cold air 

 from without, and also to exclude insects. The 'outer walls 

 should be at least 9 inches thick if solid ; but a still better plan 

 is to build the wall hollow in the centre, so as to enclose a 

 stratum of dry air, the cold or frost resisting properties of 

 which are well known. The wall-plates and rafters should be 

 of the best red deal or pine, well painted, and the whole glazed 

 with 21 oz. glass free from specks or rings. Common white 

 deal rafters and wall-plates, although cheaper in the first in- 

 stance, soon commence to decay when subjected to a hot 

 humid atmosphere. The internal fittings and arrangements 

 are self-explanatory. Access to the cellar can either be made 

 from the shed or stoke-hole at one end of the structure, or by 

 a trap-door in the floor of the house, a short ladder or pair of 

 steps being used to effect the descent. 



As a rule, the propagating house or pit is a kind of 

 sanctum sanctorum, a holy of holies, into which the high 

 priest alone /'. e., the propagator or other responsible per- 

 son, is allowed to enter; and this is almost a necessity in 

 most cases, since the thoughtless plucking of a single flower 

 may destroy the hopes of months, and perhaps years. Apart 

 from its use in the way of raising seeds, rooting cuttings, or as 

 affording the requisite conditions for insuring the success of 

 delicate surgery and manipulation in the way of grafting, 

 budding, or inarching, the propagating house is generally 

 selected as the best place for conducting experiments in the 

 crossing or hybridisation of tropical plants, and it thus becomes 

 a most attractive source of recreation to the intelligent hor- 

 ticulturist, be he master or man. The ventilators of houses 

 used for hybridising experiments should be covered with wire 

 gauze or perforated zinc, so as to exclude bees and other 

 honey-seeking or pollen-eating insects. Give an earnest hybrid- 

 iser a snug little heated pit or house about the size of a 

 saloon railway carriage, and what has he not in his power to 

 accomplish in the way of originating nqw forms of vegetation ! 

 In trade establishments, small span-roofed houses are added to 

 the propagating department, and in these the young cuttings, 

 seedlings, or grafted plants are grown on for sale. 



Most plant-growers are aware of the good results attainable 

 in low span-roofed structures where every plant is close under 

 the glass, and consequently fully exposed to the light. Our 

 market-growers, who produce hundreds of fine sturdy little 

 flowering-plants for the London markets every week during 

 the season, appreciate these structures very highly; and the 

 best of them are content with these low houses, and a series of 



