Officer "of the" or "in the"?

[Buba]

What is the correct English language terminology to state an Officer's rank AND branch?
E.g. Grzegorz Trzetrzelewski would present himself as Lieutenant of Engineers/Artillery, or as Lieutenant in the Engineers/Artillery?

BTW - Trzetrzelewski is a an authentic, if rare, Polish family name. A girl by that name, trying to make a singer's career in the USA, chose to go by her first name only

 

[The Whispering Monk]

Usually just "British Army Officer" or "Country Branch Rank" when talking about another officer.
If an officer is identifying themselves, they probably wouldn't even mention their country. More like, "I'm Major Gordan. I'm the Brigade's Fire Support Officer."

Hope that helps answer your question.

 

[Buba]

It's not about the country, it's about the Branch/Corps.

Artillery Major Gordan
or
Major in the Artillery Gordan
???

 

[The Whispering Monk]

It's not about the country, it's about the Branch/Corps.

Artillery Major Gordan
or
Major in the Artillery Gordan
???

Rank will always precede name, at least in the US military.
Your first example would work, but the second would not.