Among his more outlandish endeavors were an attempt to fly and to travel underwater in machines that he designed and built himself (in the former he broke his legs and the latter nearly drowned).
Acquainted with many odd handicrafts, he opened a shop as curiosity dealer and china and picture repairer at 22 Frederick Street, where the sign over the door described him as a "polyartist".
[2] In the 1830s John Howell, polyartist is listed as living at 67 Thistle Street, in Edinburgh's New Town, close to his shop.
[2] Howell on one occasion attempted to use a flying machine in what are now the West Princes Street Gardens, but broke one of his legs in the experiment.
At another time, having made, at considerable expense, a model in the shape of a fish, he entered the submarine, tried to swim under water at Leith, and was nearly drowned.