Quote: Forget His Feeling...

I recently encountered an interesting quote. It is from William Wordsworth’s The Prelude, considered to be the masterpiece of this English Poet who lived from April 7, 1770 to April 23, 1850. Though the poem is autobiographical, this portion is largely based on the experience of a well-known Christian.

And I have read of one by shipwreck thrown
With fellow sufferers whom the waves had spared
Upon a region uninhabited,
An island of the deep, who having brought
To land a single volume and no more—
A treatise of geometry—was used,
Although of food and clothing destitute,
And beyond common wretchedness depressed,
To part from company and take this book,
Then first a self-taught pupil in those truths,
To spots remote and corners of the isle
By the seaside, and draw his diagrams
With a long stick upon the sand, and thus
Did often beguile his sorrow, and almost
Forget his feeling…

Care to hazard a guess as to whom Wordsworth refers?