A ‘Whitworth’ protractor for field sketching and map reading, with time scales for Cavalry and Infantry, made of boxwood by J H Stewart Ltd  1914-1928 (c); used and invented by Brig Dysart Edward Whitworth MC, Indian Army and 2nd Lancers (Gardner’s Horse).
The ‘Whitworth’ protractor was designed by (then) Lt Dysart Edward Whitworth for facilitating the instruction of NCOs in the Indian Army and was used in the cavalry School, Sangor, India. 
From a collection of items associated with Brig Dysart Edward Whitworth, 2nd Royal Lancers (Gardner’s Horse), 1890-1974.