58 FRUIT CULTURE UNDER GLASS. 



merely be sMning on the end of a lean-to. Besides 

 this, a span-roofed house, from 20 to 24 feet wide, en- 

 closes a larger volume of air than a lean-to of the same 

 width, and this is of much importance in vine culture. 

 In large airy houses grapes are better flavoured, are 

 more fleshy, and consequently hang better through the 

 winter. After considerable experience in grape-grow- 

 ing in lean-to houses, ranging from 6 feet wide to what 

 may be termed large airy vineries, I unhesitatingly re- 

 commend that they be built large and roomy. Besides 

 the reasons already named, large vineries can be fired to 

 a given temperature more steadily than small ones, be- 

 cause a large volume of air is not so easily influenced 

 by external variations of temperature, just the same as 

 a thin wedge of iron is sooner heated and sooner cooled 

 than a thick one. Kg. 7 represents a span-roofed 

 vinery of the dimensions I recommend for ripening 

 grapes late in summer and autumn to hang through the 

 winter. It will be observed that a drain runs in the 

 draining material from the front to the back of the bor- 

 der in fig. 6, terminating in an upright shaft just below 

 the hot-water pipes at the back of the vinery and at 

 the front of the outside border, thus communicating 

 with the external atmosphere and that of the vinery. 



These drains should be constructed 6 feet apart the 

 whole length of the border, and be open jointed, so that 

 the air from them can find its way right and left among 

 the open rubble, which should form the lower stratum 

 of the drainage. This is for the purpose of what has 

 been termed aeration, which means the exposure of 

 the soil to the air from under-currents. No doubt, for 

 summer forcing, it is beneficial, especially in wet cli- 

 mates, to open the mouths of the upright shafts in hot 



