With Colonel Bouquet, the 42nd marched to the relief of Fort Pitt during Pontiac's War.
Drummers and other band members wore different uniforms from the rest of the regiment.  Bandsmen acted as stretcher bearers during the battle, while drummers signaled commands to the regiment with different drumbeats.

The origins of the name "Black Watch" are somewhat uncertain and a matter of disagreement among historians. The name applies both to the regiment and its tartan, which was both the first military tartan and the first modern tartan. Earliest documents about the Highland Companies in the 1660s refer to their "watch" and suppression of various crimes including blackmail (i.e. protection money paid as insurance against cattle theft, the word "blackmail" itself also being of Highland origin). It is not clear whether these companies wore a uniform tartan before their regimentation in 1739. The "government" tartan adopted about that time was a dark blue, black and green sett which looked almost black from a distance and contrasted sharply with red coats. Although the Oxford English Dictionary cites two sources (1822 and 1864) in support of the notion that "Black Watch" was in reference to the colour of their dress, many historians now agree that the "blackness" of the tartan is not the origin of the name, but rather that the government-issue tartan later took its name from the regiment.

http://www.42ndhighlandregiment1815.co.uk/

http://www.regiments.org/regiments/uk/inf/042-751.htm