100 



VETERINARY HYGIENE 



or loft above the animals. The object of the system is to provide 

 for the free escape of foul air at the most suitable point, namely 

 the roof apex, in combination with efficient lighting of the building 

 _ without the introduction 



of wall windows or the 

 ordinary form of roof 

 skylight. Throughout 



the entire length of the 

 building both sides of the 

 ridge open upwards as 

 shown in figure 40. This 

 is accomplished by finish- 

 ing the roof boarding and 

 slating about 1 foot short 



FIG. 40. Findlay's method of ventilating a o f the ridge at each Side 

 cow-shed. For details of construction . , - 11 . 



see the text. * tne ro * an( * *"l m g tne 



opening with glazed sashes 



which, being hinged at the lower edge, open upwards as shown in 

 the figure. This will give a ventilating opening 1 ft. 8 ins. wide 

 with a roof built to a pitch of 30 degrees, and provided that the sides 

 of any upper purlins and bridles are kept perpendicular. The sashes 



FIG. 41. A Roof Skylight fitted with a quadrant. 



are connected with a lever which by one movement can easily 

 regulate the opening to the desired width. If so desired, the sashes 

 can be divided into two or more sections and the two sides of the 

 building be made to operate independently. To those who have not 

 tried this system it might appear that down-draughts might take 

 place, but it is found in practice that this does not happen. Objection 



