THE SPAN-ROOFED. 13 
crops of various kinds, but as the season advances, 
span-roofed structures erected in open positions frequently 
afford the best results. Houses of either of these forms 
(lean-to and three-quarter span) may also be erected against 
east, west, or even north walls, but in the latter position 
they are only of use for the culture of ierns, palms, 
lapagerias, and other shade-loving subjects, owing to the 
lack of sunlight, or in the height of summer to preserve 
or retard flowering plants of various kinds. 
To return to the span-roofed form. Houses of this class 
may run, or trend, either north and south, or in an easterly 
and westerly direction. For most purposes the former is 
found to be the best position, as the occupants then receive 
the full benefit of the sun in the mornings and evenings, 
while during the middle of the day, when the sun’s rays 
are often injuriously strong (in summer), they are 
“broken” to a considerable extent by the sash-bars, etc., 
the sun being then ‘‘end on,” as it were. In such 
structures the plants also receive the light more fully and 
equally on both sides ; but on the other hand, in winter, 
when every ray is precious, they do not get so much sun 
as those standing in houses running the other way. Where 
plants are to be forced early in the season, or grown for 
winter flowering, one or more span-roofed houses running 
east and west will be found very suitable, and with the 
addition of moveable blinds on the south side, similar 
structures will do capitally for gloxinias, begonias, orchids, 
and other delicate plants that require to be shaded from 
strong sun in summer. North and south houses do not 
require blinds, a dash of whitewash over the glass in very 
bright summer weather being usually quite sufficient. 
