DESCRIPTION OF HOTHOUSES. 131 



fires, which is (particularly at times) of con- 

 siderable importance. 



The pit for the bark bed should extend 

 nearly the whole length, and the width in pro- 

 portion to that of the house, from five to eight 

 feet, leaving a passage or walk all round between 

 the flues and the pit, of eighteen inches or two 

 feet. The walls of the pit should be about three 

 to three-and-a-half feet in height, composed of 

 thin brick -work, sinking the bottom about one 

 foot below the surface, unless the soil is naturally 

 wet underneath; in that case it is better not 

 sunk at all. The bottom of the pit should be 

 paved with bricks or paving tiles, and the top of 

 the brick-work be secured with a plate of wood. 

 In large pineries of considerable width, two pits 

 are sometimes erected, to range parallel, one 

 before the other, separated by a passage be- 

 tween, the largest and highest pit behind for the 

 large fruiting pines, and a lower and smaller one 

 in front for the succession of small plants ; and 

 when the house is of great length, a division 

 across the centre of the pits is very convenient, 

 and, where the width of the house will permit, a 



