TOBACCO BARNS AND SHEDS. 



195 



should be used for covering the brick flues for a short 

 distance, and then No. 18 or 20 will suffice. 



Recently the flues have been greatly simplified and 

 are now made of iron pipe from 10 to 15 inches in diam- 

 eter. The flues run continuously from b to c and from 

 c to d, coming out on the side of the barn where the 

 furnaces are fed and some three feet higher than the 

 furnaces. Sometimes there is only one pipe for convey- 

 ing the smoke outside the barn. In this case, the gap 

 between c and c is filled with a flue pipe, into which a 

 single pipe for the escape of the smoke is inserted. Or 



FIG. 50. VERTICAL LENGTHWISE SECTION OF FIG. 49. 



the two pipes, c d and c d, may be united near the 

 exit into one discharge pipe. 



Cheaper flues are made by digging ditches in the 

 floor of the barn, from 15 to 18 inches wide and about 

 an equal depth, and covering them with sheet iron. A 

 pipe for conveying the smoke outside must be inserted. 



Mud walls are sometimes built by packing moist 

 clay between two boards and beating it down. These 

 mud walls are from 12 to 18 inches apart, and some 10 

 to 12 inches high. When covered with sheet iron, and 



