Source: Civil War Widows' Pensions, Iowa, Cavalry, Regiment 4, Company F. Page 17.
"In the application of Esther Harsin for pension o. 22.711:
I, T.J. Zollars, Captain of Company "F", 4th Regiment of Iowa Cavalary, being duly sworn, do on my oath, state that William M. Harsin, who was a private in my said company and regiment, and who died on the 4th of May, 1863, while in the service of the United Stated, of disease contracted therein, as stated in my certificate while captain of said company, and now on file in Department of Pension Commission,
And I do state and certify that at the time of the said deceased entered the service he was in good health and able bodied and that while he was in the service as aforesaid, his habits were eminently temperate and correct, and that he was faithful in the performance of his duty.
T.J.Zollars (findagrave.com)