VENTILATING 



123 



through the numerous small openings be- 

 tween the panes of glass. 



Side Ventilation. Side ventilation is of 

 little service, except during the summer 

 months, as the opening of these ventilators 

 in winter would expose the plants to a direct 



Fig. 66. Greenhouse showing A, side ventilators; 

 B, overhead or roof ventilators 



current of cold air which would prove fatal. 

 Side ventilating sash are usually hinged at 

 the top and open outward and upward. 

 Probably less than 50 per cent, of the com- 

 mercial houses in the country are equipped 

 with side ventilation, though it is often con- 



