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The writings of the author, which have 

 been selected for publication with this 

 Memoir, either as the most interesting in 

 themselves, or as affording the best exhi- 

 bition of his character and talents, are, an 

 Essay upon Single Vision with two Eyes, 

 and an Essay upon Dew ; a Letter to the 

 Right Honourable Lloyd, Lord Kenyon, 

 relative to some conduct of the College 

 of Physicians of London, posterior to the 

 decision of the Court of King's Bench, in 

 the case of Dr. Stanger, and containing 

 observations on a principal ground of that 

 decision; and an Account of a Female of 

 the White Race of Mankind, part of whose 

 Skin resembles that of a Negro ; with some 

 observations on the causes of the differences 

 in colour and form between the white and 

 negro races of men. The last of these 

 writings was read before the Royal Society 

 in 1813, but was never printed until now. 

 It was put by the author into the hands 

 of the editor, with an express permission 



