Ned,
Here's another painting by him of the same event in 1785:
http://www.artchive.com/web_gallery/E/E ... .1840.html In this picture too there is another paddle steamer, in the centre background (although I can't tell whether it's the same one!) I can't find anything out about the artist, but since both paintings are dated 1840, that is obviously around the time he was working. There is actually another of his works, of yet another balloon above Dover, but I believe this is actually supposed to be in 1840 (confusing, huh?) He seems to have had a penchant for balloons - and paddlesteamers!
By that date of course, paddle steamers were quite normal and the screw propeller was also just coming into vogue, the Great Britain for example dating from 1843. However I think 1785 would certainly be too early for even paddle propulsion and although there are various, and conflicting, claims as to who had the first non-sail powered sea going vessel, I don't think there were any before the late teens of the early nineteenth century. The Americans claim that their Savannah was the first ship to cross the Atlantic under her own power in 1819, but this has been disputed by others who say that she used her sails for part of the way, thus invalidating their claim. The British Aaron Manby crossed the Channel in 1822, but the earliest river paddle steamer would appear to be the Charlotte Dundas, operating on the Clyde from January 1803:
http://en.wikipedia.org/wiki/Charlotte_DundasI was just wondering whether: a) since the paddle steamer was quite common by 1840, Cocks had a mental block and just assumed that they had been around before that (doesn't seem likely); b) he decided to put the first balloon crossing and the modern transport of his day, the paddlesteamer, in the same painting (perhaps straining credulity); c) he didn't know and couldn't have cared less! The 1785 Channel crossing, was not of course the first balloon flight – there were others such as that by the Montgolfier brothers in the 1760's – but, apart from crossing the English Channel, it was apparently the first to use hydrogen – and also seems to have had an American crew. Perhaps they should lay claim to that instead - although I imagine they quite possibly have!