What was written on the paper that Charley found inside the envelope in the lesson third level by jack Finney?

Charley read the note that confirmed the fact that the third level was true. The note signed by Sam also read that he had been at Galesburg for two weeks and was enjoying himself there.

Sam had urged Charley and his wife Louisa to keep looking for the third level till they could find it and join him. It was worth the effort.