22 JETHliO WOOD; 



durable impressions of the matters to which 

 he lays claim, he sends herewith a model of 

 the due form and proportion of each, as a just 

 exhibition of his principle and of its applica- 

 tion to the construction and improvement of 

 the Plough, requesting that the same may be 

 kept in the Patent Office, as a perpetual me- 

 morial of the invention and its use. 



In the first place, the said Jethro Wood 

 claims an exclusive privilege for constructing 

 the part of the Plough, heretofore, and to this 

 day, generally called the mould-board, in the 

 manner hereinafter mentioned. This mould- 

 board may be termed a piano-curvilinear 

 figure, not defined nor described in any of the 

 elementary books of geometry or mathematics. 

 But an idea may be conceived of it thus : 



"The land-side of the Plough, measuring 

 from the point of the mould-board, is two feet 

 and two inches long. It is a strait-lined sur- 

 face, from four to five and one-half inches 



