John Irvine was employed as Surgeon Superintendent on the convict ship Canton to Van Diemen's Land in 1840. He kept a Medical Journal from 24th August 1839 to 17 January 1840.
He joined the ship at Deptford - On 5th September the Guard was received on board consisting of two officers and 40 rank and file of the 96th and 80th regiments. At noon on that day the Canton was taken in tow by a steamer and dropped down the river. They arrived at Spithead on 13th September where the surgeon reported to the Office of the Rear Admiral Superintendent in the dock yard. He then went on board the Leviathan Hulk at Portsmouth to inspect the convicts to be embarked.
On the 14th September 240 prisoners were embarked from the hulks York and Leviathan.
Linus Wilson Miller
Linus Wilson Miller, an American lawyer who sympathised with the Canadian Patriot cause, was one of the State prisoners transported on the Canton. He had been taken from Canada and imprisoned in Newgate prison, London for six months before being embarked on the Canton. During the voyage to Australia he became friends with the surgeon John Irvine and mentions him several times in his later publication Notes of the Exile to Van Diemen's Land
CHAPTER XIX. (Extract)
The middle deck of the Canton, from the main hatchway forward, formed a floating prison for 240 men, during a voyage of two thirds the circumference of the globe. Two tiers of berths, large enough for five men each, were fitted up on either side, and thirty hammocks were slung at night in the intermediate space. The height between decks was six feet eight inches. Two large hatchways, always kept open, but secured with iron bars, -ventilated the prison. The floor and berths were clean, and a proper regard to the health of the prisoners appeared to be scrupulously observed.
For convenience in rationing, they were divided into twenty-four messes of ten men each. Eleven ounces of ship biscuit of an inferior quality, one half pound of salt meat, one pint of pea soup, or five ounces of flour made into a plain suet pudding, one pint of sweetened tea for breakfast, and the same quantity of cocoa for supper, were allowed each man daily. A small. quantity of wine, or lime juice, was also served to each man, as a preventive to scurvy, a disease well known on convict ships, and indeed any vessel in which salt provisions are used during a long voyage. Vinegar was likewise allowed for the same purpose.
Two men were selected as cooks for the voyage, which duty they performed satisfactorily to all who were not particular about 'the peck of dirt.'
Twelve men were formed into a constabulary, whose duty it was to maintain order and report all irregularities to the surgeon, Dr. John Irvine, R. N., who visited the prison daily, and heard any complaints which the constables or men might make. The prisoners were under his exclusive charge, and the captain had no right to interfere, except in cases of emergency.
He received from the government, as a compensation for his services, one guinea per man, for those only whom he landed at Hobart Town; thus making it his interest to treat them well. He was an Irish gentleman of mild deportment and christian principles, and had served professionally in the British navy, for twenty years.
The safe custody of the prisoners was entrusted to Lieut Colonel Hulme, of the 96th, with a guard of forty men. Most of his regiment were already in Van Diemen's Land, and this officer was going out with the detachment to join them.
On Sunday, September 22d, 1839, at half past ten o'clock, A. M., the boatswain piped, 'All hands weigh anchor.' As the sailors manned the windlass and half chanted, half sung, the customary song, so touching and appropriate to the occasion, it seemed to me that the anchor of hope, which held my soul to earth, was being torn from the rock of faith, and confidence in God.
Linus Wilson Miller described the day they arrived in Van Diemen's Land -
Land! Land! Van Dieman's Land! How the word flies through the ship! What feelings of pleasure, or horror, thrill the breasts of the various inhabitants of our little floating world! The captain, the British officer, and the kind hearted surgeon pace the quarter deck with quick step, occasionally taking a look through the glass, and exchange glances of mutual satisfaction as the wind freshens on our starboard quarter. The soldiers and sailors., forgetting their usual jealousies, crowd together on the forecastle, and anxiously watch to catch a glimpse of their common mother earth, and talk of anticipated pleasures - At 7 o'clock, P. M., January 12, 1840, the Canton dropped her anchor in Hobart Town harbor, and thus ended a voyage of sixteen thousand miles in sixteen weeks.
 Ancestry.com. UK, Royal Navy Medical Journals, 1817-1857 . Medical Journal of John Irvine on the voyage of the Canton in 1840. Original data: The National Archives. Kew, Richmond, Surrey.
 L. W. Miller, Notes of an exile to Van Dieman’s Land comprising incidents of the Canadian rebellion in 1838, trial of the author in Canada, and subsequent appearance before her majesty’s Court of Queen’s Bench, in London, imprisonment in England, and transportation to Van Diemen’s Land