Born on July 4th, 1771. He was appointed Surgeon's Mate on the Hospital Staff, not attached to a regiment, on April 8th, 1794, and on June 16th, 1795, became Surgeon, without purchase, to the 5th Dragoon Guards. His war record is remarkable. He served under the Duke of York in Holland and in Ireland during the 1798 Rebellion, and under the Duke of Wellington in the Peninsula. He imputed his very early promotion from an Assistant to full Surgeon to the following incident: During a skirmish in Holland a cannon-ball carried away, in the Duke of York's presence, both thighs of a private soldier. His Royal Highness asked if there was a surgeon present. Coates, then a very young assistant surgeon, stepped forward, and the Duke placed the man under his especial care. The patient did well, and Coates found himself gazetted full Surgeon in the following year. On February 28th, 1812, he joined the Staff and was stationed at Hillsea as Staff-Surgeon. He retired on half pay on January 25th, 1815, and for twenty-seven years practised in Salisbury, and was Surgeon to the Infirmary. He drew half pay for the last time up to March 31st, 1853, says Colonel Johnston, who infers that he died soon after. His death actually occurred at his residence in Salisbury on April 3rd, 1853. He was succeeded in practice and at the Infirmary by his son, William Martin Coates (qv).