John William Hallion was born in Edinburgh, Scotland c. 1790 He was on the list of surviving men entitled to Naval General Service Medal clasps for actions between 1793 and 1827. He served as Assistant-Surgeon on the Alfred . This was probably at the invasion of Guadeloupe. John W. Hallion was entered in the Navy List of Medical Officers in 1814.
He was Surgeon-Superintendent on two convict ships to Australia:
The Alexander departed Ireland 4 November 1815 with 84 female convicts and arrived in Port Jackson 4th April 1816. On arrival John Hallion wrote a letter of recommendation and requested that ten of the women of the Alexander be exempt from being sent to Van Diemen's Land. He returned to England on the Guildford in June 1816.
The Isabella departed Portsmouth 3 April 1818 and arrived in Port Jackson 14 September 1818 with 227 male convicts. John W. Hallion kept a Medical Journal from 1 March 1818 to 22 September 1818. The voyage of the Isabella was not an easy one. Only 11 days out from port a private ordered into handcuffs for insolent and contemptuous behaviour, committed suicide by jumping overboard. On the 18th April John Hallion became aware of a 'serious and alarming conspiracy' to take the ship. Depositions were taken but there seems to have been no further action taken. He did not intend to remain long in the colony, no doubt keen to return to his new wife Margaret Catherine Liephardt whom he had married in December 1817. He departed the colony on the Isabella in October 1818.
John Hallion married Margaret Catherine Liephardt on 22 December 1817 at St. Marys, Lambeth. Following are some of the children of Margaret Catherine and John William Hallion - John William, baptised 20 October 1818; Matilda was baptised in 1820; Catherine baptised in 1821; George Alexander baptised in 1823; Isabella in 1826; Louisa Ursbet in 1829; Fanny baptised in 1831; Matilda baptised in 1831; Thomas Charles in 1833; Henry Henry Brook in 1836; Julia in 1837
Subscriber 1823- 24
He subscribed to the Medico Chururgical Review and Journal of Medical Science in 1823-24 giving his address as 6 Upper Conway street, Fitzroy Square.
John W. Hallion was on the List of Surgeons retired in 1841
London Medical Directory 1846
John Wm. Hallion 64 Warren street, Fitzroy Square. Surgeon; Qual., in practice prior to the Act of 1815; Royal Navy Seniority No. 10 1810; Fell. Med. Chir. Soc. Edin. George Alexander Hallion, 64 Warren Sreet Fitzroy square. Gen. Pract; Qual., M.R.C.S. April 21 1845; L.S.A. Dec. 19, 1844. 1861
John Hallion age 70, can be found in the 1861 Census residing at Marylebone with his wife Margaret (who was born in Hamburg) and four of their adult children, all unmarried....Catherine age 38 is a Governess; Louisa age 30; Charles age 27, a copying clerk and Julia age 23.
Medical Register 1865
He was on the Medical Register List of 1865. Residence: 29 Charrington St. St. Pancras, London. Qualifications Surgeon in the Navy 1810.
John William Hallion died in Charrington Street, Oakley square, St. Pancras, Co. Middlesex aged 77 on 13th April 1868.  His Will was proved by the oath of Mary Catherine Hallion of the Vicarage Sutton Valence near Staplehurst, Co. Kent, spinster, his daughter.
Notes and Links
1). Goddard, Johnathan Charles, The navy surgeon's chest: surgical instruments of the Royal Navy during the Napoleonic War. Journal of the Royal Society of Medicine. - Surgery performed by John Grey, surgeon of the Alfred in 1810.
2). Journal of HMS Alfred by John Gray, Surgeon Reference: ADM 101/83/4 Description: Journal of HMS Alfred by John Gray, Surgeon for 31 August 1810 to 31 August 1811, during which time the ship was deployed in Cadiz Bay and off Cape Trafalgar.
 Ancestry.com. UK, Naval Medal and Award Rolls, 1793-1972 [database on-line]
 Bateson, Charles., The Convict Ships, p.36
 Source Citation: London Metropolitan Archives, Saint Mary At Lambeth, Register of marriages, P85/MRY1, Item 398. Source Information: Ancestry.com. London, England, Marriages and Banns, 1754-1921