C 400 ] 



A description of the improved patent Bark Mill, er ma^ 

 chine for threshing Grain, called the Pennsylvania 

 Rubber, with directions for using, by Caleb Church- 

 man and George Martin, Jun, 



Read June 14, 1814. 



A, represents an upright shaft, with an iron gudge- 

 on in each end, standing on the centre of the barn floor, 

 or other place where the machine is intended to be 

 used ; B, a wheel five feet in diameter, eighteen inches 

 in thickness in the centre, and twelve on the tread, 



