317 



the supports being closer together and m ar the centre the con- 

 tinuous clerestory is placed vertically above the posts and has 

 vertical lights on either side, a proportion of winch would be 

 made to open for ventilation and would be controlled from below, 

 but casements would be required for the glazing, a material addi- 

 tion to the cost, and the controls are apt to get out of gear and 

 cause trouble in adjustment. 



In Scheme B the central dunging passage admits of the sup- 

 ports being placed nearer the side walls and by carrying up the 

 braces, sloping sides are obtained to the clerestory which admit 

 more light. Alternative suggestions are shown for the lighting 

 and ventilation, viz., either fixed glazed casements, or rein- 

 forced glass secured direct to the framing by the same method 

 as in greenhouse roofs. Allowance is made for expansion and 

 contraction by means of galvanised clips, while provision would 

 be made for the escape of condensation. 



Ample ventilation is obtained by raising the curved corrugated 

 iron or asbestos top of the clerestory two or three inches above 

 the framing by means of blocks placed at intervals. This space 

 is protected by close mesh wire to keep out birds and insures 

 adequate cross ventilation above the flat ceiling of the clerestory. 



To let out the hot and foul air rising from below it is sug- 

 gested that this flat ceiling could be cheaply formed of battens 

 spaced half an inch apart similar to Yorkshire space boarding 

 and as it is continuous throughout the whole length of the shed 

 the extraction of air would be so distributed as to obviate any 

 possibility of draughts. An alternate method of ventilation 

 panels is shown in the model, one in each roof bay, but the 

 former method is considered by far the better and cheaper and 

 likely to prove the more efficacious in actual working. 



It is also suggested that as the top lighting in this scheme 

 would be ample the openings in the side walls immediately in 

 front of the cows should not be glazed but should be fitted with 

 simple adjustable louvre shutters such as are commonly found 

 in the midland counties. Thus fresh air would be admitted and 

 the supply regulated in the feeding passage by means of the 

 adjustable louvres, the openings in the clerestory acting entirely 

 as outlets. The actual inlet ventilation area of the two louvres 

 in each bay would approximately equal the outlet ventilation 

 area between, the spaced boarding in the flat ceiling. 



It is seriously suggested that the provision of closely spaced 

 louvres in the lower openings would overcome the great dim- 



