Dan wrote,
"I'm trying to find an ancestor who supposedly sailed >from Bremen to
Baltimore on the Koeln on July 2, 1899. When looking at the passenger
lists for this time period, I did not see any listing for the Koeln.
Is there a way to find out when and where this ship sailed around this
time? (The Morton Allen directory doesn't list the Koeln until 1901)."

The NARA (National Archives) has an index of Baltimore arrivals, if my
memory serves me, cover the dates you are interested in. If you can find
your relative in the index you can request a copy of the passenger list

from the NARA.

Are you sure that your relative arrived in 1899? I seem to have spent
years chasing arrivals that were one or more years in error. My ancestors
had the ships correct but not the year.
Barry Chernick
CHERNICK, CHERNIK, CZERNIK - StaroKonstantinov, Krasilov, Volocisk
MITTLEMAN - Tchan (Tiofipol), Satanov
SCHULMAN, SHULMAN - Dolhinov, Minsk, Bialystok
KARP, CARPE ? Minsk, Bialystok

MODERATOR NOTE: Yes, there are indexes to the Baltimore arrivals.
See http://www.jewishgen.org/infofiles/PassLists/Baltimore.html