THE TALE OF A TROOPER is a first-hand account in novel form of World War I by soldier, author, and distinguished New Zealand activist for the blind, Clutha N. Mackenzie.   Blinded in action in 1915, while serving with the Wellington Mounted Rifles in Egypt and Gallipoli, Mackenzie presents a profound chronicle of the global warfare as seen from the eyes of an ordinary soldier -- by an author who will never see again.