This is the original article by Soros in case you missed it.  NPR's Noah 
Adams did a piece based on this article which is available on the
interrnet.

Mark Twain, one of America's greatest literary legends, was a passionate
guitarist and singer during the 19th century's Romantic era. His songs
were woven with graphic stream-of-consciousness imagery, and his musical 
styles included gospel, slavery blues, love songs, political satire, folk, and burlesque.

   Twain obtained this Martin guitar, style 2 1/2-17, shortly after the
outbreak of the Civil War in 1861. It was built by C.F. Martin Sr. in
1835, the same year that Twain was born and the year that Haley's comet
returned (amazingly, Twain died the next time the comet appeared, 75
years later). The guitar has Brazilian rosewood back and sides, a spruce 
top, and an ebonized ice cream-cone cedar neck with a slim, modern feel. 
It features fan-braced construction, an ebony pyramid bridge, and a
herringbone rosette. The instrument's finish and ornately engraved
tuners with ivory buttons are still in great shape.

    Twain played his Martin frequently-for the newspaper men of the
Nevada Territories, the miners of California's Gold Rush, passengers
aboard the clipper ship Ajax bound for the Hawaiian Islands, and the
willing women of the West. On December 15, 1866, he sailed from San
Francisco on the steamer America to New York via Panama to seek fortune, 
in his words, "leaving more friends behind than any newspaper man that
sailed out of the Golden Gate." He had become a national celebrity and
was listed on the ship's manifest as Mark Twain, barkeeper. On the
Martin's coffin case was a shipping label bearing his nom de plume and
destination written in his own hand: "Mr. M. Twain, New York." In 1997,
document experts working for the U.S. Department of Justice and the
Engraving Printing Bureau of the U.S. Treasury authenticated the
shipping label. Just before Twain's death in 1910, the guitar was
entrusted to Colonel John Hancock III (great grandson of American
founding father John Hancock), a U.S. Cavalryman, horse breeder, and
guitar collector. The guitar remained in the Hancock family for four
generations.