5{M SCRI^W ADJU&TIN6 FtOUGB. 



v^ocid of the firs is of a beHutifu) j-eliow white, till exposed 

 to lb€ air> when it becomeis a deep brick red. 

 I am, Sir, 



Voiii* obliged servant, 



AGNES IBBETSON. 



Description qf a Screw adjusting Plough ^ invented hy Mr, 

 Thomas Balls, of Saxlingham, near Holt, Norfolk*, 



SIR, 



f|ov»li on a J[ HUMBLY offer, for the inspection of the Society, the 

 ^^^^ model of a plough, constructed upon a principle on which I 



have made itHveral. 



Sir Jacob Astley, Bart., has seen two at work on nay farm, 

 which I have constantly used, in different kinds of plough- 

 ing, for three years, and which, excepting in the share, 

 hare not cost me a shilling in repairs* Sir Jacob has or- 

 dered one to be made; and he being desirous, that the 

 plough should be more generally known, expressed a wish 

 that i would send a model to the Society. If its mecha- 

 nical principle proves to be of real utility to agriculturists, 

 and superior to the ploughs in general use, I shall be highly 

 gratified in my endeavours to promote the liberal views of 

 the Society. 



I am. Sir, 



Your most obedient humble Servant, 



Sarlhgham, April 5, ISIO. THOMAS BALLS. 



Certificate from Sir Jacob Heney Astley, Bart. 



BEAR SIR, 



Tesrtnrm of T have seen Mr. Ball's plough worked against the com- 



its uiiliiy. ^^^ Norfolk plough, and find it much superior. It laid the 



furrow rauqh better, more equal, and with much less draught 



• Trans, of the Soc, of Arts, Vol. XXVlII, p. 45. The silver jne- 



dai was voted to Mr, Balls for this invention. ' - • i*' 



to 



