The latter suited him because of his noiseless gliding movement, bright eyes, and ethereal diet.

It was first given to him by Byron during a reading of "Faust".

When he came to the line of Mephistopheles, "Wie meine Muhme, die beruhmte Schlange," and translated it, "My aunt, the renowned Snake," Byron cried, "Then you are her nephew." Shelley by no means resented the epithet.

Indeed he alludes to it in his letters, and in a poem already referred to above.
Soon after Trelawny's arrival the party turned their thoughts to nautical affairs.

Shelley had already done a good deal of boating with Williams on the Arno and the Serchio, and had on one occasion nearly lost his life by the capsizing of their tiny craft.