PINE CULTURE IN SOUTH WALES. 281 



bed from the bottom, Mr. B. considering it better that all 

 moisture should proceed from the surface, and he finds no 

 difficulty in providing a sufficiency of moisture at the bottom of 

 the bed, and near the pipes. The heating apparatus is so arranged 

 that both top and bottom-heat is produced at the same time, and 

 without the use of stop-cocks. The pit is about 50 feet long by 

 16 feet wide. In building it the earth was excavated sufficiently 

 deep to admit of the heating apparatus, or rather the pipes for 

 bottom -heat being placed so that when the soil or compost is 

 filled in to the depth of eighteen inches it is level with the 

 surface of the surrounding soil. No side lights are used, but 

 under each sash a framed shutter or ventilating door, about three 

 feet by two feet, is placed, and the space between the doors, 

 about two feet wide, and under each rafter is filled in with four- 

 inch brickwork. Half of these doors are hung by hinges at the 

 top, and the other half swing on pivots at the sides, the object 

 being to have the ventilation as free and plentiful as possible. 

 Air is also admitted by the top sliding lights, the roof is span, 

 with a long light on the south side, and a short one on the north 

 side. All these sashes are moveable and are glazed with common 

 sheet glass at "i^tZ. per foot. The boiler for heating, one of 

 Mr. Barron's own invention, is fixed at the west end, the pipes for 

 surface-heat enter and traverse to the east end close by the wall, 

 and return within three feet of the boiler, then for bottom-heat 

 dip, return to the east end, return again and enter the boiler. On 

 the north side the surface-pipes run by the end and back wall to the 

 east end of the pit, then dip, and taking one turn under the bed 

 return to the boiler. Of course the three lengths of pipe under the 

 bed are divided equally over the surface. At first sight it may occur 

 to practical men, as it did to me, that in this arrangement there 

 might be some danger of getting too much bottom-heat in severe 

 weather, but it will be observed that on the south side the heat 

 traverses 80 feet before it enters the bed for bottom-heat, while 

 on the north side, where the circulation is slower, it has to go 

 50 feet before it returns under the bed. As a point of economy 

 it may be thought that as bottom-heat must be had in warm 

 weather, it would be more economical to have had separate 

 arrangements for top and bottom-heat, but Mr. Barron says he 

 finds advantages rather than any disadvantage from the present 

 arrangement, while he has saved the expense of stop-cocks, which 

 are not only expensive, but are very frequently out of order. To 

 ensure success in floriculture, air in large quantities must be 



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