William Trail studied at Aberdeen, then he studied under Simson at Glasgow. In 1766 he was appointed to the Chair of Mathematics at Marischal College, Aberdeen preferred to Playfair and Robert Hamilton. He resigned in 1779 on obtaining a preferment in the Irish Church.
Trail published Elements of Algebra... and a biography of Simson. He was described as
a man of great capacity... entirely extinguished... by the sinecure emoluments of the Irish Church.