Some of the ship manifests don't correspond to where they should be on the actual films.
Go to Stevemorse.org that compensates for such mistakes.... and you will be able to track down the correct manifest....... using the various tools on that site. What you want is in the Ellis Island folder......
Added Note: You are wrong. If you went to the Ellis Island folder on the morse site, and choose the ships list utility, it would take you to the Missing Manifests portion. You can see manifests directly with this approach. However, so saying this, I tried to see the images for your ship. The morse site shows that it comes in on June 30, 1910, gives the roll, volume, and frame number, but cannot get there. So..... what I would do is to email Steve Morse directly. Explain the problem and that the Missing Manifest utility is not working, and ask for advice. Steve is at Roots Tech starting today, but he usually responds to such emails and likes these puzzles.
Added Note 2: Obviously, you didn't follow my advice, so I emailed Steve and asked about this situation. He found that Ellis Island apparently has changed the way they display Roll 1509, and thus Steve Morse's correction was not working...... it is now.
http://stevemorse.org/cgi-bin/boat.php?series=&rollStart=&rollEnd=&volumeStart=&volumeEnd=&monthStart=&dayStart=&yearStart=&monthEnd=&dayEnd=&yearEnd=&boatkind=starts&boat=Themistocles&offset=1&portkind=starts&port=&pageSize=50&database=all&local=yes&auth=
Joel Weintraub