127 



obtained in a higher or wider house. Both the walls 

 and flue must stand on arches, to permit the roots of 

 the trees to extend themselves in every direction 

 beyond the limits of the \valls, for w^iatever be the 

 more remote causes of mildew, the immediate cause 

 generally appears to be want of moisture beneath the 

 soil, with much dampness above it. A bar of wood must 

 extend from d to b, opposite the middle of each lower 

 lihgt, to support it when drawn down. {Knight's 

 Papers, 186.) 



The angle recommended by Mr. Knight as being- 

 best for the peach-house is 34 degs. 55 min., suppos- 

 ing that the greatest attainable amount of light is re- 

 quired in May. This, however, was calculated for the 

 latitude of his own residence, Downton, in Hereford- 

 shire ; but as the latitude and the time when most 

 light is required vary, we give the following rules as 

 detailed by Mr. Caie, whereby any one may ascertain 

 the most desirable angle for the roof of his peach- 

 house, accordingly as circumstances vary. 



In the construction of forcing-houses, the proper 

 angles should be selected to suit the period intended 

 for producing each particular crop, and to be adapted 

 for different latitudes, to receive the most vertical rays 

 of the sun for ripening the fruit. The sun's declina- 

 tion in each month : — 



DEG. MIN. 



Jan. 21, the declination is, south . . 19 52 

 Feb. 21 „ „ 10 29 



