William Thomson (1824-1907) Lord Kelvin, Baron of Largs
Baron Kelvin of Netherhall, Largs
(knighted Nov. 10th 1866, raised to the peerage in 1892)

Argent, a stag's head cabossed Gules, on a chief Azure a thunderbolt
Proper winged Or, between two spur revels of the field.   [1866]
Crest:  A cubit arm erect vested Azure, cuffed Argent,
the hand grasping five ears of rye Proper. 
Supporters:  Dexter:  A student of the University of Glasgow, habited [Gules],
holding in the dexter hand a marine voltmeter.
Sinister:  A sailor habited [Azure], holding in the dexter hand a coil, the rope passing
through the sinister, and suspended therefrom a sinker of a sounding machine, all Proper. 
Motto (over the crest):  Honesty without fear.