Honourable augmentations to the Ross family arms were granted to John Ross and James Clark Ross after the discovery of the north magnetic pole. They included an augmentation to the shield (a half globe with the location of the pole indicated) and the addition of not one but two crests: a Union Jack, gilded with the date "1st June 1831", above a dip circle on one; and a cute fox head on the other. One crest for each Ross? I've no idea how this stuff works, and I'm not about to become a heraldic nerd on top of everything else. I am NOT emailing the College of Arms and asking them to rifle through their records.
Anyway, given Eleanor Franklin's letter, the augmentations must have been granted before 1840.
The family motto is Spes Aspera Levat (Hope Lightens Difficulties).
Both men used the coat of arms, which passed to and was used by JCR's descendants. I've been hoarding all know examples - catalogued below.
JCR's service plate / JCR's tea service, a gift from Crozier and Bird / John Ross ex-libris / At the entry to North West Castle, John Ross' one time residence in Stranraer, Scotland / James Coulman Ross ex-libris / In Fox-Davies' "Armorial families: a directory of gentlemen of coat-armour" (1905)