Captain Horatio Ross, a leading Scottish rifleman and sportsman made the following remarks in 1868: “The Hythe kneeling position is an admirable one for soldiers and when firing in line, but it is not good for match shooting, or for skirmishing, especially if there be a strong wind. Almost all the good shots now shoot lying on the ground flat, and resting both elbows on the ground. Some shoot lying on their backs; and a countryman of mine (Farquharson) makes marvellous scores in that position; but almost all those who have imitated him have failed.”
Sportascrapiana, edited by C.A. Wheeler (Simpkin, Marshal & Co., London, 1868)
An interesting passing reference to target shooting positions and the use of the back position in the UK.
Some further notes can be found at: The Back Position