Dr. Adair who is going on his private business to Virginia being introduced to me by a Gentleman of my acquaintance here, I avail myself of the opportunity of forwarding to you the model of the threshing machine which I have been so long in getting the mechanic who made it to finish. He has made it upon the improved plan of Mr. Adam’s which will execute much more than one I saw first at Mr. Patersons but of course it requires more power. He has with my consent adapted it both to the power of water and of horses; this gives it the appearance of being more complex and has rendered it more expensive, the whole cost now being 13 Guineas, though he at first said he could make a simple one for 5. Every part which in the model is of Brass may be made of wood except the two long fluted Cylinders which in the original is of cast iron, which is necessary on account of the weight as it is by the pressure alone of the upper one that they hold the grain to the threshing wheel—the joint in the end of the upper wheel must be observed—by means of this they thresh even the large horse beans; of wheat the original of this threshes 150 bushels in 8 hours with six horses and 5 Men. 5 bushels is a days work for a labourer to thresh by hand in the same County. The scale is ½ an inch to a foot. Dr. Adair has seen these machines work in Scotland and will be able to give any explanation that may be necessary. With sincere esteem & respect I remain Dear Sir Your most obedient and most humble Servant