680 Journal of Agriculture, Victoria. [10 Nov., 1917. 



upward continuations of the wall? of tlie furnace room, and may be 

 built of matclied lumber nailed to 2 x 4 framing, or, better, of metal 

 lath and plaster. 



The two ends of each tunnel iwc formed by the doors, which must 

 be close fitting, of a height and width equal to the inside dimensions of 

 the tunnel, and must swing back far enough to permit ready insertion 

 or withdrawal of trays. The roof of the tunnels should be of matched 

 lumber. The ventilating shaft, for three tunnels each 20 x 3 feet, 

 should be not less than 5x2 feet in cross-section, should have a 

 damper at its base, and should extend well above the peak of the roof of 

 the building (see diagram Fig. IV.). 



The partitions .separating the individual tunnels are built of matched 

 lumber and are carried up to within 12 or 18 inches of the roof of the 

 tunnel. Some operators omit these partitions entirely, merely making a 

 framework of 2 x 4's, to which the cleats which support the trays are 

 nailed, so that the whole interior of the three tunnels is one continuous 

 chamber. If the tunnels are walled up, the opening of one of the doors to 

 insert or withdraw a tray interferes with the drying in that tunnel only, 

 whereas in the absence of such walls the opening of any door results 

 in the cooling down of the entire system. Even were this not the case, 

 the more uniform and rapid movement of air through the tunnels, and 

 the comparative freedom from dead-air pockets secured by the separating 

 walls, well repays the expense of their construction. 



The Fdknace Room. 



If built in accordance with the suggestions made above, the furnace 

 room will be 22 x 10 feet in size. Tke height to the floor at the lower 

 end of the tunnel .should be 7 feet; a rise of 1| inches per foot in the 

 floor would give, a height of 9^- feet at the opposite end, while a 2-in. 

 rise would give a height of 10 ft. 4 in. The walls may be of stone, 

 brick, concrete, or metal lath and ' plaster ; if built of wood, they must 

 be lined with asbestos sheeting to reduce the danger of fire. Since the 

 cost of such a lining will bring the expense of construction very nearly 

 up to that of a concrete wall, it is the part of wisdom to cut the fire 

 risk to a minimum by avoiding wood altogether. 



Adequate provision for an abundant supply of air is absolutely neces- 

 sary. For three tunnels of the size here suggested, the furnace room 

 should have four air inlets, one in the centre of each of the walls, each 

 3 X 1} feet in size, and placed about 6 inches above the ground. These 

 will give a total air inflow of 2,592 square inches. It will rarely be 

 necessary to open all of the inlets to their full capacity, and sliding doors 

 should be provided in order that any of the inlets may be partially or 

 wholly closed at will, but there will be an occasional still, humid day 

 when the entire capacity of the air-intakes will be used 



If the furnace room occupies only part of the lower floor of a larger 

 building, jjrovision must be made for free access of air to the intakes 

 on the enclosed sides. This may best be secured by excavating the 

 furnace room to a depth of 12 to 18 inches, elevating the floor of the 

 remainder of the building, and providing numerous ventilating openings 

 in the foundation walls, through which air may move freely beneath 

 the floors to the furnace room inlets. 



