328 



CASSELL'S POPULAR GAEDEXIXG. 



end facing the south, the other the north, the hfting 

 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, but also to form separate and 

 moderate-sized outlets for the two currents of air 

 rising from the base ventilators fixed on the east and 

 west sides of the house. When the yentilating 

 lights are placed on one side only, and the base 

 ventilators on each side are of equal capacity, the 

 two currents do not tlow evenly, consequently this 

 mode of apex ventilation is imperfect. 



Lantern Ventilators. — For a considerable 

 time after cheap glass was 

 introduced, the lantern mode 

 of \'cntilation was confined 

 to the roofs of large struc- 

 tui-es, including conserva- 

 tories, requiring an abundant 

 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. Foster and 

 Pearson, of Beeston, Xotts, 

 who have 

 made the lan- 

 tern a speci- ^> ■ 

 ality, haye 

 recently fa- 

 youred me 

 with a mast 

 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 light ; arrangements are 

 made also to prevent the rain entering at either end 

 when the cover is raised. • These ventilators have 

 ])een found to efficiently ventilate a house up to 

 thirty feet in width." 



Fig. 78 is another lantern ventilator, which can be 

 made any size up to three feet in width, from a to b : 

 but three-feet openings are quite sufficient for the 

 largest span-roofed houses where the temperatiu-c 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. 



S'ront Ventilation. — Having glanced at the best 

 modes of letting out the "sitiated air, we now come 



to the equally important methods of introducing a 

 continuous stream from the external atmosphere 

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

 designed for himself by Mr. AV. Thomson, of Cloven- 

 fords, and in which he has gi-o^\Ti those magnificent 

 Grapes that have made his njime known and hon- 

 oured throughout the horticultm-al world. The roof, 

 as will be observed, is Jixcd. The apex ventilating 

 lights are 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 iron, or gas tubing, 

 running the entii-e 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 sudden ingi'ess 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 

 health of the 

 plants that 

 it be moist 

 as well as 



Thcmson's Tiuerv. 



warm. 



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

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

 vantages, for the same apparatus will supply cold 

 fresh air, warm fi-esh air dry, or warm fresh aii- 

 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 ^-ith or without the apparatus at pleasure. I'pon 

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

 an introducer of cold or warm 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. AVhen n is 

 horizontal, as sho's\Ti at e f, the slide closes and the 

 apparatus becomes an ordinary ventilator. 'SMien 

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



