The Letters of William S McCaskey Author:Hank Chapman The letters of William Spencer McCaskey give a first hand account of what he witnessed during his four years in the Civil War with the 1st and 79th Pennsylvania Infantry Regiments. He enlisted in April 1861, during Abraham Lincoln's first call for 75,000 troops, as a 17 year-old private, and retired in 1907 as a Major General in the Regular Army.