I'm an Academic Herald. I'm not a "real" herald; I don't design and register people's coats of arms (though I can certainly suggest designs for those who might be interested). What I do is study, research, teach, and write about heraldry. (You can find some of my books about heraldry and a list of my articles and presentations about heraldry at "Our Website" below.) And I like to share what I have learned about heraldry, hence this blog. I hope that you'll find it informative, interesting at least occasionally, and worth your time to come back. Got a question? Comments? Feel free to ask or let me know. I'd love to hear from you. You can find my contact information in my Profile.
According to the post, seventy men from this unit were transferred into the Royal Artillery to accompany General John Burgoyne's expedition down from Canada in 1777. They were captured by American forces following the battle of Saratoga.
The button (which is available for purchase from The Military Campaign at http://www.themilitarycampaign.co.uk/badges/product/296-royal-regiment-of-irish-artillery) shows the arms of the Royal Regiment of Irish Artillery. I have not found a color emblazon of the arms anywher, but I would assume that the field is azure (blue) with the golden harp of Ireland; the cannon would be either gold or silver, as would the chief, which has the Royal crown (normally gold) and two roundels representing cannonballs (probably black, which are sometimes blazoned, appropriately enough, as gunstones, though they have also been blazoned as pellets and as ogresses). Were I to guess at a blazon, I believe it would most likely be: Azure, in pale an Irish harp Or stringed Argent and a cannon Or [or Argent], on a chief Argent the Royal crown Or between two gunstones [or, roundels Sable].
Whether my speculative blazon is correct or not, it was still a neat bit of historical heraldry that played a role in the American Revolutionary War.