508 



AGRICULTURAL ENGINEERING 



Design of Windows. The window casings should be 

 designed to intercept as little of the direct sunlight as possible. 

 Stone or concrete walls of considerable thickness should be 



beveled on the inside so 

 as to let in the full width 

 of the beam of sunshine 

 passing through the 

 glass. For this reason 

 windows that are long 

 vertically are more de- 

 sirable and more effi- 

 cient than those which 

 are wide but low. In 

 the latter instance the 

 casings and wall cut off 

 a large proportion of the 

 direct light admitted. 

 Again, wide, over-hang- 

 ing eaves cut off much 

 direct sunshine from the windows located directly below. 



Size of Windows. No definite rules can be given for the 

 amount of window surface to provide in barns and other farm 

 buildings, owing to the fact that the efficiency of the windows 

 depends so much on their location. It is good practice, how- 

 ever, to provide one square foot of glass for every 20 to 25 

 square feet of floor surface. Judgment must be used in this 

 connection, varying the amount with the location and shape 

 of the windows. Dairy barns are generally provided with a 

 larger window area than horse barns. 



There is a tendency to go to the extreme in lighting dairy 

 barns. Many barns have been built during recent years with 

 entirely too much window surface. Such buildings are too 

 cold when located in the northern climates, at least. Ade- 



Fig. 312. A sketch showing the effect 

 of thick walls upon the amount of direct 

 sunlight admitted, the greater efficiency 

 of deep windows over shallow windows, 

 and also the effect of over-hanging eaves. 



