[1] He is notable for having served Prince George, Duke of Cambridge as bandmaster in the British 4th Regiment, 12th Lancers.
In 1854, his bandmaster, Herr Schallehn, left service and traveled to England, joining the Crystal Palace Company.
[1] Hartmann continued to play cornet in the Crystal Palace Band until he was offered the position of bandmaster of the Tyrone Militia at Sheffield.
He served with them, with the 1st (King's) Dragoon Guards, and with the Royal Sherwood Foresters (Nottingham Militia), who were "one of the best brass bands in the country."
[1] Afterwards he returned to Germany, and not liking it, retired again in the UK, doing compositions and arrangements of music for British publishing companies.