John Macauley Hamilton was born on Orkney Island in 1799, son of Rev. Gavin Hamilton and Penelope Macauley. 
He was appointed assistant surgeon on 13 September 1826.
Surgeon on Buffalo 1833
He was appointed Assistant Surgeon on the convict ship Buffalo on 21st January 1833.
The Buffalo departed Portsmouth on 12 May 1833 and arrived in Port Jackson on 5 October 1833 with 178 female prisoners. A Medical Journal was kept from 17th May to 10th October 1833.
Pigot's Directory 1837
In 1837 Pigot's Directory he is listed as Surgeon at Stromness Orkney Island (south end).
In the 1851 Census John Hamilton resided at Stromness, Orkney with his wife Marion age 42. Others in the house hold included Marion age 18, Gavin age 15, John age 13, Helen Hamilton age 11, Margaret age 9, Katharine age 7, Thomas age 4, Colin age 3 and Jessie age 1. 
He was described in The Reminiscences of Doctor John Sebastian Helmcken.....
I saw Dr. Hamilton the medico, a tall quiet well built man - who had a big open sail-boat with which he used to visit patients in the neighbouring islands and of course was a good sailor. I had to leave one of our men with him for axillary abscess, as no one wished to have helpless people aboard. He introduced me to Mrs Ray (Rae), a venerable old lady - very nice and quiet. Dr. John Macaulay Hamilton married Marion, a sister of Dr. John Rae and the couple later joined her brothers Richard and Thomas in Hamilton, Upper Canada. 
British Medical Directory 1854
He is listed in the British Medical Directory 1854...... Address Stromness, Orkey. M.R.C.S. Edin. 1826; formerly R.N. (Retired).
The family immigrated to Canada in the 1850's
John Macauley Hamilton died at Hamilton, Ontario Canada in 1872. 
 Scotland Births and Baptisms, 1564-1950,'database, FamilySearch, John Mccaulay Hamilton, 28 Nov 1799;Hoy and Graemsay, Orkney, Scotland, index based upon data collected by the Genealogical Society of Utah, Salt Lake City; FHL microfilm 990,502.