32 



LOGGING 



It has a round tapering shell (A) of sheet metal, with an inner 

 wall; an outlet (B) at the side for the discharge of sparks and 

 cinders; and a sheet metal cover (C). A cone-shaped screen 

 (D) attached to the sheet iron cover hangs within the stack, apex 

 downward, and deflects the cinders into the spark receiver at 

 the head of the outlet pipes. The steam, smoke and gas escape 

 through the screen, in which the cinders do not clog because of 

 its conical form. The screen can be raised by means of the lever 

 lift (£) when it is unnecessary to use an arrester. The size of 

 arresters for locomotives is governed by the cylinder area, and 

 those for logging engines by the diameter and height of stack 

 used. The list price ranges from $io to $27 each. 



Spark Caps. — A successful spark arrester,^ Fig. 4, in use by 

 a logging company in Pennsylvania consists of a j-inch mesh 



Closed 



Fig. 4. — A Locomotive Spark Cap. 



wire cone-shaped spark cap, 24 inches high and 18 inches wide 

 at the base, where it is attached to a ring, which is hinged to 

 another ring in the top of the stack. When in position the cone 

 is fastened down on the stack by a hasp. When not in use the 

 arrester may be dropped by the side of the stack. During the 

 fall and winter the caps are removed and stored until the follow- 



^ Described in Forestry Quarterly, Vol. IV, No. i, page 2. 



