to a
person beyond the extent of his journey, he must at least carry it to
the next post-office, if he was going so far; and from that, some other
Brother would pass it along. It was death, in all cases, for a member to
open a letter not directed to him.

As Brothers are constantly passing along the line, in both directions,
considerable despatch was secured. If a letter should chance to be lost,
it was written in such a manner that one not knowing the secret would
suppose it to be an ordinary business letter, and the persons alluded
to were so mentioned as that only the individual to whom the letter was
addressed, or some person interested in the same transaction, could
understand the allusion.

The person to whom the letter was addressed must return the letter, if
requested, but might keep a copy. Along this mail line lived many of the
Brotherhood, and as they knew each other by signs, and were able to
converse in a _flash language_, unintelligible to the community
generally; when we recollect that they were bound by solemn oaths to aid
and defend each other in every emergency, right or wrong--that both men
and women belonged to the order--the reader will see what security a
villain could enjoy when hunted by the police; how easily the
_respectable_ citizen, the country merchant, the lawyer, the captain of
a steamboat, could conceal the fugitive, and put the officer upon the
wrong scent.

In addition to this caution, any thing which must be so explicit that a
stranger to the order might understand, if he should see it, was written
with sympathetic ink, which would appear only when heated, and would
disappear again when cold; and even this was written in a perfectly
unintelligible cipher, to which, however, I very fortunately found the
key among the letters. I insert it for the benefit of the curious.

One of the most profitable branches of their business was that of
_trading in horses_. For this, as will be seen, their combination gave
them peculiar facilities.

One of the _common_ robbers steals a _horse_, rides it fifty or a
hundred miles, and offers it to a _respectable_ robber, called a
_trader_. If it do not appear a dangerous bargain, he makes the
transaction as public as possible; he takes a bill of sale, and enters
it on his books, and the common robber goes on his way rejoicing.
Presently the owner comes along, and _claims the horse_. The
_respectable_ trader is very much astonished at the discovery, b