write to a wholesaler in New York for some stuff. When I buy a book
I mark in the back just what I paid for it, then I know what I can
afford to sell it for. See here."

He pulled up a book from behind the seat--a copy of "Lorna Doone" it
was--and showed me the letters _a m_ scrawled in pencil in the back.

"That means that I paid ten cents for this. Now, if you sell it for
a quarter you've got a safe profit. It costs me about four dollars a
week to run Parnassus--generally less. If you clear that much in six
days you can afford to lay off on Sundays!"

"How do you know that _a m_ stands for ten cents?" I asked.

"The code word's _manuscript_. Each letter stands for a figure,
from 0 up to 9, see?" He scrawled it down on a scrap of paper:

m a n u s c r i p t
0 1 2 3 4 5 6 7 8 9

"Now, you see _a m_ stands for 10, _a n_ would be 12, _n s_ is 24,
_a c_ is 15, _a m m_ is $1.00, and so on. I don't pay much over
fifty cents for books as a rule, because country folks are shy of
paying much for them. They'll pay a lot for a separator or a buggy
top, but they've never been taught to worry about literature! But
it's surprising how excited they get about books if you sell 'em the
right kind. Over beyond Port Vigor there's a farmer who's waiting
for me to go back--I've been there three or four times--and he'll
buy about five dollars' worth if I know him. First time I went there
I sold him 'Treasure Island,' and he's talking about it yet. I sold