"I got so drunk last night I was blowing bubbles..."
[do NOT go there -ed]
Don't take these percentage moves as gospel.
When I went home last night I was troubled by the South Seas Bubble number given here, 750%, because I have it stuck in my head that the stock went ten-fold, £100 to £1000. The 1845 British railway bubble is also problematic. I don't know of any index that the chartmeisters could use to derive the 100% figure from and individual issues exceeded that degree of movement, some increasing 500 or 600%.
Also, a lot of the railway issues were subscriptions which meant that the 'scrip' traded (not legally) prior to the issuance of the stock.
There may be other errors but on the whole the orders of magnitude are right.