14 JETHRO WOOD; 



to present to the Philosophical Society the re- 

 sult of my philosophical researches since my 

 retirement. But, my good Sir, I have made 

 researches into nothing but what is connected 

 with agriculture. In this way I have a little 

 matter to communicate, and will do it ere long. 

 It is the form of a mould-board of least re- 

 sistance. I had some years ago conceived the 

 principle of it, and I explained it then to Mr. 

 Bittenhouse. I have since reduced the thing 

 to practice, and have reason to believe the 

 theory fully confirmed. I only wish for one 

 of those instruments used in England for 

 measuring force exerted in the drafts of dif- 

 ferent ploughs, etc., that I might compare 

 the resistance of my mould-board with that 

 of others. But these instruments are not to 

 be had here. In a letter of this date to Mr. 

 Bittenhouse I mention a discovery in animal 

 history, very signal indeed, of which I shall 

 lay before the society the best account I can, 



