According to the book that accompanies the PBS documentary by Ken
Burns, Twain smoked "Wheeling long-nines," which would have been made
in Wheeling, West Virginia, by Marsh Wheeling & Co., beginning in 1840.
They were indeed about nine inches long, about a 52 ring at least in
diameter and were covered in a "maduro" wrapper which means they were
likely nearly jet black. This means they were rather large, menacing
cigars just sitting in the box even by the standards of the
machine-made cigars produced in the post-Civil War era.
Whether he smoked 28 of these "gigantics" every day seems not likely,
as some of the extant pictures of Sam Clemens show him with much
smaller cigars on and around his person. (And this isn't even close to
the number of pipes he has been photographed holding and smoking.)
The really big question, one dear to former President Clinton's sense
of theater, was whether or not Clemens actually inhaled. The current
medical literature posits a reduced risk of cancer for pipe and cigar
smokers who do not inhale, at least versus regular cigarette smokers.
(All not exactly at the top of the health charts!)
A big mystery, as others have noted, is why smoking seems to affect and
effect some people more than others. It almost seems, at least from the
circumstantial evidence, that Clemens' smoking did Livy a far worse
turn in life than Sam.
As another related for instance, my great-grandfather (who was a
medical doctor no less) chain-smoked unfiltered cigarettes all his
life. He lived until he was 87, in excellent health until his final
month. And all this on only one lung, his having lost one to mustard
gas in World War I!
B. Adrian van der Wel, M.F.A.