One notable incident of its application was in early 1817, when a young man, Joseph Abney, apparently used it to stop the flow of blood of a little girl who had fallen off a roof. This was remarkable because, according to Gilbert Norrell, the spell had been "lost for hundreds of years", yet Abney performed it fluidly, without having had any prior magical training. This demonstrates the effect of Strange's actions in reminding the stones, trees, rain etc. of England - which of course at John Uskglass's behest had once undertaken to be the allies of Englishmen - that their former obligations were still binding. In Abney's case, although he had some slight acquaintance with magic beforehand, he merely knew the names of such spells; yet he claimed after he had performed them "that the trees and the sky had told him what to do". When he hears this Mr. Norrell impatiently dismisses it as "Mystical nonsense!"; but there is little doubt that Abney was merely stating simple fact. It appears that as a consequence of Strange's reminders, at this point whenever an English person in dire need appealed for help - consciously or otherwise - then in accordance with their pact the trees and sky gave the necessary assistance.
NOTES AND QUERIES:
Allow me to inform your readers that Teilo's Hand, as you describe it above, should not be confused with another, rather macabre, item often used in magic of old, the "Hand of Glory" - though its magical uses are perhaps not that dissimilar.
As all of us must have learnt by now, a Hand of Glory was the carefully-prepared and "pickled" hand of an executed felon, cut off while the body still hung from the gallows, and commonly used by house-breakers to send sleepers in a house into a coma from which they were unable to wake.
In one version the clenched hand is used as a candleholder for a candle incorporating human fat; but in another, the outstretched hand has its own fingers lit. (In this case should one of the fingers refuse to light it is a sign that someone in the household remains awake.) In either case the light cannot be extinguished by water or pinching, but only by quenching in either blood or else "blue" (skimmed) milk - the usual method in magic and witchcraft.
With the greatest respect I remain, sir,
Yr. obedient servant,