The 25th Regiment, later the King’s Own Scottish Borderers [KOSB], was raised in Edinburgh in 1688 and is now part of the Royal Regiment of Scotland. Portraits of sergeant-majors were rare. The details here come from a contemporary water-colour of several members of the regiment, one being the sergeant-major. His uniform, with its silver lace and smart cut, resembles that of an officer, as it would to-day. The hat developed from the style of 1680-1707 to the tricorne shape of 1743. The front ‘cock’ has almost disappeared and begins to resemble the modern version of the cocked hat, worn until recently by the quartermasters of the Foot Guards. A turned-down collar like this is shown on the coats of several Foot Guards privates depicted in the Blenheim tapestries, but it was a fashion which was short-lived because there is no sign of it again until about this date when it was worn almost universally for a few years. The turned-back skirts of the coat have become stylised and less clumsy, and the cuff has a slash with four buttons. In the picture on which this plate is based, only the sergeant-major and drummers are shown with slashes, the rest of the regiment having plain buttoned cuffs. The uniform of the sergeant-major, as for the drummers, was decided by the commanding officer, and often purchased by him, to conform more to his wishes than to regulations.
Source: A series of watercolours of the Regiment.