53 



The outlet shaft for foul air, WD, should be in duplicate and 

 should be abauit 1 foot by 2 feet inside measurement. The best 

 construction is boards running vertically, two ply with inch airspace 

 and two papers between. The opening at the top should be roofed, 

 (see B). The roof should be supported on four posts, AA, leaving a 

 clear space aboiuit 15 or 16 inches between top of shaft and bottom 

 of roof B. The amount of air to escape by these shafts in any given 

 time may be controlled by means of a key as at E. The key may be 

 regulated by cords F F. The key should never be entirely closed. 

 Where the shafts are large enough, there is no objection to their 

 being used as chutes for feed or litter, but care should be taken to 

 so hang the door as to insure its remaining tightly closed when not 

 held open to allow of shaft being used as a chute. 



The fresh air inlets require careful consideration. The method 

 on the left is very simple of installation. The passage through from 

 K to I should be about 12 inches by 7 inches, the greater dimension 

 being horizontal. K is a protection or roof, H the intake, I the 

 outlet into the stable through which the air passes with an upward 

 tendency. J is a guard or board so placed as to direct air currents 

 upwards. To do this, it will need to extend about 4 inches above 

 top of opening through wall. It will, of course, be nailed to the 

 projecting 7 inch sides of this fresh air shaft inside the building, 

 just as K will be nailed to the same sides outside the building. These 

 passages might be controlled by means of small keys or hinged 

 covers, but it is not usually necessary or advisable to so control tha 

 intake shafts. 



The method on the right hand side admits air by the passage N, 

 12 inches x 7 inches below the level of the floor. Air enters this 

 passage at L under shelter of the snow and rain guard M and flows 

 into the stable at 0, with an tupward tendency. The cement or 

 wooden guard X is to prevent c 1 ' "t or dust being knocked or swept 

 in. The top or opening shouM be protected by a grating of some 

 description. It is possible, but seldom necessary or advisable, to 

 provide these inlets with keys or controls. If it is found necessary 

 to use some system of control, then the control Z had better be out- 

 side the building but inside the guard cabin M where it can be 

 reg>udated by a cord passing out at P. 



The careful installation of this system of ventilation, with 

 either method of , fresh air intake, will insure an abundance of good 



