28 MISC. PUBLICATION 4 3 4, U. S. DEPARTMENT OF AGRICULTURE 



A different type of scarifier was recently developed by the Lake 

 States Forest Experiment Station {32). It consists of six vertical 

 sandpaper-covered disks, 0.25 inch thick, 10.5 inches in diameter, and 



B 





Figure 9. — Disk seed scarifier developed by the Lake States Forest Experiment 

 Station. A, Exterior view; B, interior view, showing screen in bottom to allow 

 dust to escape. 



mounted on a %-inch steel shaft, revolving inside a stationary metal 

 cylinder also lined with sandpaper (fig. 9). The cylinder is 24 inches 

 long, 11 inches in diameter, and is made of 28-gage galvanized iron. 

 The ends are of 1-inch pine. A narrow 16-mesh screen is soldered in 

 the bottom and left uncovered to allow dust to escape. The cylinder 



