338 



Rural Architecture. 



which weaken very materially the pieces. Where a judi- 

 cious selection is made in placing tLe joists, laying the in- 

 herently weak pieces in places where little strain can come 

 upon them, much saving of lumber may be made. 



413. Selection of Lumber to Increase Carrying Capacity.* 

 It is possible to greatly increase the carrying capacity of a 

 lot of joists or of a set of beams by giving attention to the 

 lumber used, selecting the evidently strongest pieces for use 

 where it is known the heaviest strains will come. Some- 

 times a joist should be reversed or turned the other side up 

 in order to enable the piece to render its highest service. 

 In the arrangement of joists under a hay bay or granary, 

 where heavy loads are to be carried, the cross-grained pieces 

 and those with exceptionally large knots should be well dis 

 tributed among the stronger ones, making the evidently 

 weak come between those evidently above the average in 

 strength. 



414. Braces. There are two principles underlying the 

 use of braces to give greater strength to lumber. (1 ) That 

 of equalizing the load, making "it fall more heavily upon 



