The younger John entered his father's business, and from 1823, after his father and brother died, conducted it alone. Those were the days when steam was coming into vogue, and he began to manufacture high-pressure steam-engines. Together with Ericsson, he constructed the "Novelty," the locomotive which competed in the famous railway-engine contest at Rainhill in 1829, when Stephenson's "Rocket" won the prize. Braithwaite's engine, though it did not fulfil all the conditions of the competition, yet is said by some to have been the first locomotive to run a mile a minute--or rather more, for it is held to have covered a mile in fifty-six seconds. He used a bellows to fan the fire; and in his steam fire-engine, he also employed bellows, though on one day of the Rainhill contest the failure of the bellows rendered the locomotive incapable of doing work. In the fire-engine, the bellows were worked by the wheels of the machine, and eighteen or twenty minutes were required to raise the steam. At the present time, a hundred pounds of steam can be raised in five minutes in the biggest engine of the London Brigade, this result being due, in one respect at least, to the use of water-tube boilers. Braithwaite's engine of 1830 was fitted with an upright boiler, and was of scarcely six horse-power; but, nevertheless, it forced about fifteen gallons of water per minute from eighty to ninety feet high. The pistons for the steam and water respectively were on opposite ends of the same rod, that for steam being 7 inches in diameter, and for the water 6½ inches, and both having a stroke of 16 inches. The engine was successful in its day. During an hour's work, it would throw between thirty and forty tons of water on a fire; while another engine, also made by Braithwaite, threw the larger quantity of ninety tons an hour. The steam fire-engine was first used at the burning of the Argyle Rooms in London in 1830; it was also used at the fire of the English Opera-House in the same year, and at the great fire at the Houses of Parliament in 1834. But, curiously enough, a great prejudice existed against it, and the engine was at length destroyed by a London mob. The fire-brigade were also against it. So Braithwaite gave it up; but he built a few others, one at least being for Berlin, where it seems to have given great satisfaction. Braithwaite, who became engineer-in-chief to the Eastern Counties Railway, also applied steam to a floating fire-engine, and constructed the machinery so that the power could be rapidly changed from propelling the vessel to operating the pumps.