328 



CASSELL'S POPULAR GARDENING. 



end facing the south, the other the north, the lifting 

 lights should he attached to each side of .the ridge- 

 piece, not only to admit of giving air on the lee side 

 in windy weather, hut also to form separate and 

 moderate-sized outlets for the two currents of air 

 rising from the hase ventilators fixed on the east and 

 west sides of the house.- When the ventUatiag 

 lights are placed on one side only, and the hase 

 ventilators on each side are of equal capacity, the 

 two currents do not flow evenly, consequently this 

 mode of apex ventilation is imperfect. 



Lantern Ventilators. — For a considerable 

 time after cheap glass was 

 introduced, the lantern mode 

 of ventilation was confined 

 to the roofs of large struc- 

 tures, including conserva- 

 tories, requiring an ahundant 

 outlet for the heated air ; but 

 of late this excellent system 

 has been applied to smaller 

 span-roofed houses devoted 

 to the culture of fruit, nota- 

 bly to Peach -houses and 

 Vineries. Messrs. Poster and 

 Pearson, of Beeston, Notts, 

 who have 

 made the lan- 

 tern a speci- r ~~ ~ 

 ality, have 

 recently fa- 

 voured me 

 with a, most 

 elegant design 



for a roof bracket and lantern, Fig. 77. The inventors 

 say : " It allows the heated air to escape at the highest 

 point. The cover moves up and down like a parallel 

 ruler, and is raised by a worm and wheel apparatus 

 which works very easily, and being glazed it causes 

 but little obstruction to the Kght ; arrangements are 

 made also to prevent the rain entering at either end 

 when the cover is raised. These ventilators have 

 been found to efiioiently ventilate 3. house up to 

 thirty feet in width." 



Pig. 78 is another lantern ventilator, which can be 

 made any size up to three feet in width, from n to b; 

 but three-feet openings are quite sufficient for the 

 largest span-roofed houses where the temperature is 

 not expected to exceed that of an ordinary green-house. 

 The side lights are hinged to the top plate at c, and 

 open outwards by means of ventilating gear attached 

 to rods running down the sides of the columns. 



FrontVentilation. — Having glanced at the best 

 modes of letting out the vitiated air, we now come 



'W.'iji/itM^-^ygtiSioi 



Fig. 79. 



to the equaUy important methods of introducing a 

 continuous stream from the external atmosphere 

 to take its place. Fig 79 is a section of a Vmery 

 designed for himseU by Mr. W. Thomson, of Cloven- 

 fords, and in which he has grown those magnificent 

 Grapes that have made his name known and hon- 

 oured throughout the horticultural worid. The roof, 

 as will be observed, is fxed. The apex ventilating 

 Kghts axe raised by machinery, wet- weather ventila- 

 tors are provided, and the front lights, hinged to the 

 upper plate, open outwards by means of rule-jointed 

 levers keyed to a horizontal rod of ii-on, or gas tubing, 

 running the entiie length of the house. 



For admitting a continu- 

 ous supply of air, or lower- 

 ing the temperature to that 

 of the external atmosphere, 

 this system is all that can 

 be required during hot 

 weather ; but there are times 

 when the sadden ingress of 

 cold air would be fatal to 

 the inmates. How to get it 

 warmed and broken up be- 

 fore it mingles with that of 

 the house is a problem which 

 has occupied many minds, 

 as it Is gene- 

 rally neces- 

 sary to the 

 hesdth of the 

 plants that 

 it be moist 

 as well as 

 warm. 

 Use of ■Warmed Air. — ^Weeks's Hydro-caloric 

 Ventilator (Fig. 80) possesses all the necessary ad- 

 vantages, for the same appai-atus will supply cold 

 fresh air, warm fresh air dry, or warm fresh air 

 moist. In construction, it is a copper vessel three 

 feet long, one foot high, and eight inches wide, en- 

 cased in a wood frame, to be built into the front wall 

 of the house. From end to end are apertures through 

 which the air is made to pass. The ventilator is 

 attached to the hot-water apparatus, and can be made 

 hot with or without the apparatus at pleasure. Upon 

 the face, b, an indicator tells whether it is at work as 

 an introducer of cold or wann air, or as a hot-water 

 apparatus ; c is a hit-and-miss slide worked in con- 

 nection with the flap d. When d is at the angle 

 shown, the slide c is open, and the ventilator being 

 hot, the air of the house is passing through, and it 

 is serving as a hot -water apparatus. When n is 

 horizontal, as shown at e f, tlie slide closes and the 

 apparatus becomes an ordinary ventilator. "SATien 

 the flap, D, is at the angle shown by the dotted lines 



Thomson's Vinery. 



