Fis;. 26. 



Fig. 27. 



Fig. 29. 



Rules for calculating the length of shadows. — In selecting 'situations for gardens' 

 and also for planting trees for shelter, the length to which their shadows will reach 

 during winter deserves consideration, as also does that of the shade caused by halls 

 and other buildings ; for no screen should be planted so close as to shade any part of 

 the ground, nor any glass roof be erected on which the sun may not shine every day 

 in the year. 



Several rules are given for determining this. The relation between the height of 

 a tree and the length of its shadow depends on the latitude of the place and the sun's 

 declination, which latter will be found by consulting an almanack, and the former by 

 the sun-dial — at least, most sun-dials have the latitude engraved on them ; if not, the 

 of the county will give it. The height of the tree, wall, or building, and the 

 th of its shadow on the ground, form the perpendicular and base of a right-angled 



C>i^*x:S?i^ 



