250 



GREENHOUSES 



Any kind of lumber which -is free from 

 knot holes and has been surfaced to an even 

 thickness will answer for forms. If the wall 

 is a high one it may be necessary to tie the 

 sides of the form together with wire. The 

 wires remain in the concrete when the form 

 is removed, but may be cut off flush with the 

 surface, and if the wall is plastered they will 

 not be noticed. 



Fig-. 128. Form for a concrete wall 



