"Well, there! Darned if this yer ain't the rummest start 1 I ever zee!" cried Abraham Bush, staring at the sky one warm still September evening. " There's a many queer things I've a zeen. Zeen a whale and walked atop of en, terble slippy and squashy 'twas, to be sure."
The spectacle they were gathered together to wonder at and discuss was, as Mrs. Plummer was then observing to her husband, "enough to make the very cat talk." Though the sun had sunk some degrees below the purple horizon the sky was all aglow as if from some vast conflagration, and in the heart of this glow, the warmth of which could almost be felt, like that of the sun, sailed a majestic star, enveloped in and followed by a broad and fiery train.
All the lined and furrowed faces were turned towards the glow, the general expression was anxious and bewildered, the eyes of one elderly man with down-drawn mouth and harsh features glittered with an unearthly light as he watched the sky.
"'Tis a proper big vire," interposed the second carter, dubiously, "and 'tis terble warm vor the time o' year."
"Some says 'tis trouble vor the nation," Abraham interposed.
"Some says 'tis vamine and pest," added Sarah, anxiously; "some says wars. 'Tis zent vor our zins, I hreckon."
- Maxwell Gray, In the Heart of the Storm
The comet scene in the book has a strong element of pathetic fallacy, portraying via weather and sky the unease preceding Jessie's emotional storm (amid a real one) when she runs away to escape Claude. But it also seems to be a pretty accurate portrayal of the national mood at the time the novel was set, around a year haunted by a scary prediction that a Great Comet would hit the Earth on 13th June 1857, as described in The great comet, now rapidly approaching, will it strike the earth? (pub. James Gilbert, 1857). The chief mover of this theory was a divine in the National Scottish Church, John Cumming, who preached a forthcoming apocalypse via lectures and books such as his 1855 Signs of the times: or, Present, past, and future. Sources state the particular date to have been drawn out of a hat by a German astronomer (or astrologer), though I've yet to find one saying exactly who.
This "comet fright" took a particular hold in Paris, as satirized in a number of prints of the time (see 19th Century Parisian Dopes Wait for Comet). Not everyone was bothered, however. E Moses and Son, Bradford clothiers, saw a marketing opportunity:
There's a great deal of stir, and some little alarm,
Though the comet can possibly do us no harm;
Some people are talking of nations' commotions,
While others will tell us they've quite different notions.
For the comet to change our commercial affairs,
To raise up the stocks or to plump up the shares,
Make money the better or easier to get,
Would be a matter which no one would ever regret;
But some are supposing 'twill burn up the world,
As soon as its monstrous train is unfurled.
We think that the comet will do us no harm,
Though the weather most likely will be very warm,
Then to Messrs. E. MOSES. and SON take a turn,
And a fact such as this you will speedily learn,
That a stock of the neatest and cheapest array
At their Branch Mart in Bradford they ready display.
Should the season be hot in the reign of the comet,
Messrs. M.and SON'S garments will well shield you from it.
- advertisement, The Huddersfield Chronicle and West Yorkshire Advertiser, June 13, 1857
And for Benjamin Disraeli, it wasn't going to get in the way of a trip to the Westcountry.
The world is very much frightened about the Comet, Dr Cumming having declared the last day is certainly at hand ... the destructive agencies are all rife - in the centre of the earth a raging fire, while the misty tail of the comet wd, if it touched us, pour forth an overwhelming deluge — so in 4 and 20 hours we may be shrivelled or drowned. In the meantime, if the catastrophe do not occur, we hope to be at Torquay by the end of the next month."
- Letter, June 7th 1857, Benjamin Disraeli Letters: 1852-1856, Volume 6, University of Toronto Press, 2004.
Punch, similarly, had satires such as The Expected Comet on March 7th 1857 ...
Hey! a Comet's coming, Cumming, Cumming,
Ho! a Comet's coming, expected very soon;
Unless folks are humming, humming, humming,
The Comet will be here on 'the Thirteenth day of June.
... and an illustrated editorial Preface for the 27th June edition in which the comet, bored on being told of world affairs, decided not to show ... which was what exactly had happened. A few telescopic comets were seen, but there was no apocalyptically large one.
However, in 1858 a highly visible Great Comet did make an appearance without mishap; Donati's Comet, one of the brightest and most visible comets of the 19th century, and the first to be photographed. A look at the monograph An account of Donati's comet of 1858, by George Phillips Bond, shows that it reached its maximum brightness in late September 1858, when it could be seen well in the twilight shortly after dusk.
This closely fits the scene in In the Heart of the Storm. The chronology of the book is a little confusing, as the English and Indian segments overlap in time, but a closer reading finds that the comet scene takes place after "news of the final capture of Lucknow by Sir Colin Campbell had been received" (i.e. after March 1858) so Abraham and the others are definitely watching Donati's Comet.
Further reading: see Fire in the Sky: Comets and Meteors, the Decisive Centuries, in British Art and Science (Roberta J. M. Olson, Jay M. Pasachoff, Cambridge University Press, 1999). There's extensive Google preview available.
1. I'd never encountered this archaic expression before, though Google Books finds other examples of "the rummest start". The OED, however, finds "start" in this context to mean "A proceeding or incident that causes surprise", with citations between 1836 and 1905.