Castle Cornet threatens Napoleon

From Collins' Stranger's Guide to Guernsey, 1833, p. 66.

The following is an anecdote found amongst the private papers of Napoleon Bonaparte, not generally known. It states, that when the emperor was in the zenith of his power in France, he meditated a descent on the Channel Islands, to add them to the province of Normandy, from whence they originally emanated. He fitted out a strong fleet and armament, in the harbour of Brest, for that purpose; but the night previous to the embarkation of the troops, the weather proved hazy, and a mirage appeared in the air, exceedingly brilliant, and remained visible to the whole fleet and inhabitants of Brest, for several hours. It contained a clear representation of Castle Cornet, with the following lines in legible letters:

'Sheer off! quite off! I warn ye;
I ken my strength sae weel,
If you touch my isle of Guernsey,
I'll blaw you to the de'el.'

It is strange, that even men of the brightest mental faculties are sometimes so much under the influence of superstition, that trifles are often converted into insurmountable obstacles: certain it is, however, that when the above lines were interpreted to the emperor, by a Scotch prisoner of war, he relinquished the enterprise, and never again attempted the intended conquest.