MUSHROOM PESTS AXD THEIR CONTROL 



the intake, there is practically free delivery of air. In use, the fan 

 is connected to the intake, and stovepipe is led from the delivery pipe 

 into the house through an asbestos-lined opening in a false door made 



Figure 2. — A, Outside sulfur burner in operation, with door closed and fan con- 

 nected ; B, the same with door open showing arrangement of pans ; C, diagram 

 showing details of construction. 



of wallboard. It is advisable to extend the outlet, by means of sev- 

 eral extra lengths of stove-pipe, so that the delivery of gas will be 

 along the floor in the central alleyway. This gives slightly better 



