[666.1] "In alliance wi' the Rothsay":- Almost certainly the Rothsay Castle. See bar489~Wreck of the Rothsay Castle.

[666.2] "Rob Roy with elevated prow":- Many of the early steamboats had a blunt prow like the old sailing vessels whereas the ROB ROY had much finer lines.  [Ref: Professor A Graham Lappin. Private communication based on an article by him published in the Clyde Steamers magazine]. In June 1821, Rob Roy was moved to Dover where she became the first steam powered packet between England and France. Below is a steamer believed to be the Rob Roy. It agrees with the illustration of Rob Roy at Dover in 1821 See bar050~Calais Packet. See also bar669~Rob Roy Steam Vessel. 

[666.3] "The Clyde":- see below

[666.4] "Captain Wise":- Captain Wyse listed as captain of the Britannia in 1817 [Ref: Early Clyde Steamboats by Andrew McKechnie http://www.dalmadan.com/?p=1135]

[666.5] "Anither course has Marion ta'en, She's cruizing on Lochlomond":- Below is a picture of Marion taken from an advertising handbill.

Lord Jeffrey, later to become Lord Advocate complained of the Marion that ; "It is a new experiment for the temptation of tourists.  It circumnavigates the whole lake in about ten hours and it was certainly strange and striking to hear and see it hissing and roaring past the headlands of our little bay, foaming and shouting like an angry whale, but on the whole it rather vulgarises the scene too much, and I am glad that it is found not to answer, and has to be dropped next year." she was not dropped the following year but plied her trade with great success until replaced by the Euphrosyne in 1827 [Ref: http://www.valeofleven.org.uk/lochlomondsteamers.html]

The development of tourism on Loch Lomond later encouraged the construction of the Caledonian and Dumbartonshire Railway. See bar040~Bowling Railway

[666.6] "The Comet like its namesakes grown":- The Comet was the first steamboat to provide a regular passenger service in Europe. [Ref: Ransom P.J.G.; Bell's Comet: How a Paddle Steamer Changed the Course of History. p61] She entered service in 1812 and was wrecked in December 1820 on her way from Fort William to Glasgow [Ref: Ransom p91]. Below the Comet on the Clyde near Bowling

[666.7] "the Steam-boat Robert Burns":- See bar599~Lines Written on the New Steamer Robert Burns

[666.8] The following year Harriston added some more verses to this song. See bar667~Clyde Steam Boats 1819. In 1824 He self-published a volume called "The steam-boat traveller's remembrancer : containing, poems descriptive of the principal watering places visited by the steam-boats from Glasgow / by William Harriston, author of The fortunate ploughman; The intended emigrants; Wallace, or the Knights of Ellerslie; The king's arrival, or The crowded metropolis; The city mirror, or Glasgow in miniature; Poems on various subjects, &c. ..." [National Library of Scotland shelfmark AP.1.213.25]

[Note 1]  It was the ambition of the early steam coach engineers to establish services from London to the leisure resorts of the wealthy. This song pre-dates any of the successful attempts.

[Note 2] Ben Wilson writes of the Regency period that "Well-off Britons were assailed from all side by new needs and wants. [Dr Thomas] Beddoes [a fashionable doctor] wrote that a scream pursued one throughout the day : "did you see the papers today ? Have you read the new play - the new poem - the new pamphlet - the last novel?" every day there were must have new inventions advertised in the papers: labour-saving corkscrews, novel candle snuffers, even a hunting razor so that busy gentlemen shaving at full gallop need not miss a second of sport. It was a particularly British habit to lavish money on gadgets for which they had no conceivable need." [Wilson, B. Decency & Disorder: the Age of Cant 1789 - 1837; p25]

[Note 3] "As they as will can go up hill, for which they have propellers, too" 1825 John Seaward and his brother Samuel Seaward granted a patent for 'propelling locomotive engines, vehicles, and other carriages...a steam-engine' https://www.gracesguide.co.uk/Timeline:_Steam_Road_Vehicles

[Note 4] This may be a reference to a carriage built by David Gordon in 1824. The legs extended through the floor in the middle of the carriage, analogous to the legs of a horse, and the feet pushed backwards on the road to move the carriage forward. Friction was still poorly understood and engineers were not confident that the wheels alone would exert sufficient traction to move the carriage.

[Note 5] Seats inside the coach cost more than those outside. See the illustration of the coach built by Goldsworthy Gurney in 1827 the illistation appeard on the front of the Morning Chronicle 10th December 1827 many newspapers reports throughout 1827

[Note 6] It was common for the self-employed (and indeed some employees) not to work on a Monday; a practice known as keeping St Monday

[Note 7] The dangers of accidents generally and boiler explosions in particular were well founded. See Bar271 The New Steam Carriage Blown Up.

[Note 8] "Now bawling loud, among the crowd, came Patrick Denny" - Patrick Denny has not been identified but presumably he would have been known to the song's intended audience

[Note 9] The song Adventures in a Steam Boat was printed several times under various titles.

Construction of the Sheffield, Ashton-Under-Lyne and Manchester Railway began in 1837. The Ashton to Stalybridge branch, which had been part of the original plan was deferred due to lack of finances. Despite the collapse of the viaduct in April 1845, the line was completed and opened in December. Some sources say that 17 men were killed. It is likely that the song was printed within days of the accident and the discrepancy in numbers may be due to two men dying of their injuries after the accident.

Read more: The Falling Of Nine Arches And Fifteen Lives Lost At Ashton, April 19th 1845

Historic Context:

The Kentish Weekly Post or Canterbury Journal of Friday 15 June 1821 reported that “Rob Roy of Greenock arrived [in Dover on June 11^th] with the intention of carrying passengers between this and France. She sailed this morning for Calais but with very few passengers, as those in the town preferred the regular packets.”

The picture below shows Rob Roy at Dover.

Despite their initial reluctance, travellers soon saw the advantages of steam power. In August 1821 the 'Kentish Chronicle' reported "The 'Rob Roy' steam vessel continues to sail daily for France, with a number of passengers and carriages far exceeding any vessel in the employ". Later in the same month it reported that "The 'Rob Roy' on her passage to Calais met the 'Lord Duncan' (Post Office sailing packet), Capt. Hamilton, and the 'Prince Leopold', Capt. Rogers, and after landing her freight at Calais, and taking on board passengers, she came out again, and passed those vessels and reached Dover long before them."

In 1836 Cabin passengers paid 10 shillings and 6 pence, and deck passengers 5 shillings http://www.dover-kent.co.uk/transport/early_cross_channel_steamers.htm a typical weekly wage at the time was less than 10 shillings http://www.historyhome.co.uk/peel/ruralife/swing.htm

While the song does not specifically mention steam, the lines "Charming and very like Twickenham ferry, Crossing over to Calais now" imply a change of some sort and that the voyage would be calmer than previously. Paddle steamers did not have to tack  thus avoiding a manouver that caused the deck to slope to a degree likley to disconcert.the passengers.
The specific mention of a six hour passage ("Full six hours after sailing from Dover, Safely anchored at Calais at last") agrees with the advertised crossing times. In this etching by Thomas M'Lean dating from about 1828 shows the advertising bill to the left of the harp advertises 'Calais in five hours'

Notes on the Song:

A song called Calais Packet beginning "Who's for the packet were just upon starting" (Roud V302 Madden Collection (London Printers 3)) includes the line "Hollo! Stand clear I want to make a tack" so is clearly about a sail powered packet. The sung verses are quite different but the scansion of the sung verses is the same and the patter is similar The sail-powered version was printed several times and seems to have been widely known. The broadside "In support of Thomas Wentworth Beaumont, a candidate in the Northumberland parliamentary election of 1826" [British Library General Reference Collection C.194.b.119(317) ] names "The Calais Packet" as the tune to which it should be sung.
The sailing packet song probably served as the model for the song above. and was almost certainly sung to the same tune. Greenwich Coaches, a song by Thomas Hudson printed in his 13th Comic Songster in 1832 or soon after, uses the same structure.

Packet: A boat or ship travelling at regular intervals between two ports, originally for the conveyance of mail, later also of goods and passengers; a mailboat [OED]

Half seas over: Drunk

Leagues: 1 league = 3 miles (4.8 kilometers)

Wherry: A light rowing-boat used chiefly on rivers to carry passengers and goods. [O.E.D.]

pellise: A woman's long cloak, with armhole slits and a shoulder cape or hood, often made of a rich fabric; (later also) a long fitted coat of similar style. [O.E.D.]

guineas: An English gold coin, not coined since 1813, first struck in 1663 with the nominal value of 20 shillings, but from 1717 until its disappearance circulating as legal tender at the rate of 21 shillings [OED]' or cash to that value

[Note 050.1] The Twickenham Ferry crossed the River Thames in the western suburbs of London,  [Wikipedia]

[Note 050.2] Poultry Compter was a small compter, or prison, run by a Sheriff of the City of London from medieval times until 1815. [Wikipedia]

[Note 050.3] Deal is a town in Kent, England which lies on the English Channel, eight miles north-east of Dover and eight miles south of Ramsgate.

[Note 050.4] "I should like to have a song; what do you think of the storm." - The storm referred to is probably The Storm; or, the dangers of the Sea by George Alexander published c1770
The songs was printed as a broadside (Harding B 11(3670A)) and famously performed by the black street singer Joseph Johnson.

The former sailor was known in London and the home counties as 'regular chaunter' of sea songs.
He wore a large, detailed model of HMS Nelson on his head even though he had been "disabled" while serving in a merchantman. [ref: Wilson; decency and disorder]

[Note 050.5] Temple Bar - The principal entrance to the City of London on its western side from the City of Westminster. At Temple Bar the Corporation of the City of London erected a barrier to regulate trade into the City. By extension; the gateway which spanned the road until 1878.

[Note 050.6] "How are we to go ashore then? As well as we can ma'am; there's these two stout Frenchman will carry you on their shoulders" : At low tide, the quay at Calais was 'dry'. In these circumstances, passengers would be carried ashore.