AGRICULTURE AND PLANTING. 75 



On the CoTistrucfion of a Compound Roller. 



into nineteen equal parts, -and so of all the other lines alternately. In every divi- 

 sion fix an iron spike, so that there will be twenty spikes in one row, and nine- 

 teen in the other, throughout the whole circumference, making in all two hundred 

 and thirty-four spikes. That part of the spike which projects out of the wood is 

 four inches long, one inch square at the circumference of the roller, and three 

 quarters of an inch square at the point. 



The tong- which goes into the wood is four inches long, seven-eights of an 

 inch square at the circumference of the roller, and tapers to a point at the end. 



B. is the plain roller, made of a piece of oak wood, seven feet long, and 

 eighteen inches diameter. In the centre of each end of both rollers are fixed iron 

 bushes of two inches diameter. 



C. the bow part of the left hand side of the frame, made of iron, four inches 

 broad, half an inch thick, and is a segment of a circle twenty-seven and a half 

 inches radius ; fixed as per figure, for turning the rollers upside down. 



D. is the string part of the bow, five feet two inches long, and eight by three 

 inches square, made of oak" wood. In these pieces are fixed gudgeons of two in- 

 ches diameter as at a a, on which the rollers move, and are four feet one and a 

 half inches asunder. 



E E E E. the four shafts, eleven feet long, six by three and a half inches 

 square at the hinder ends, through which the center bolt passes. 



F F F F. four bars, four by one and a half inches square, and three and a 

 half feet long, for bracing the shafts together. 



G G. two bars, eight feet long, and three by eight inches square, with dou- 

 ble tenons at each end for bracing the outside frames together. In the outer ends 

 of these tenons are linchpins, for the convenience of taking the machine to 

 pieces, byt these are omitted in the plate. 



H. the centre bolt made of hammered iron, two and a quarter inches diame- 

 ter ; at one end is a round and head, at the other a linchpin, as per figure. 



