I am positive Basses is for tubas only. In this case it's an easy call, because this edition happens to have a separate String Bass part. I wouldn't bet Sousa wrote the String Bass part - it looks like nothing but a transposition of the lower tuba part (string bass plays 8vb), which is what a back room copyist would do.scottw wrote: I may be wrong [Paul?], but the usual divisi you mention is actually for string bass/tuba. Still, many bands do split the part among the tuba section, as most do not have a string bass to double. I'm just not sure that is what souse had in mind. Paul Maybery would be the one to clarify that.
More generally, these two parts tend to match up very well with contrabass and bass tuba. Low end is G -- both 3V BBb tuba and string bass go to E, but the string bass is much more convincing down there. And again, if John Philip Sousa ever did write a real string bass part, I bet a quarter it doesn't just double the tuba part (especially if he were writing for published version to be used by a wide range of bands, because a part like that isn't just musically questionable, it's hard.)
As for what Sousa had his own band doing - I'm sure Paul has as much of the story as anyone. But Sousa didn't get The John Church Company to print up an arrangement of Liberty Bell so he could pass it out to his band, and he probably didn't have them print up the arrangement they played. All these arrangements are for standard band configuration of the time, so certainly would need to account for an Eb tuba, and in this case the arrangement shows more signs of some musical intelligence at work - I mean, the line is always divided if it goes below A, but above that, a C for example may be doubled in some places, not in others, for what I suppose are musical reasons that wouldn't have motivated a copyist. So whether Sousa had an Eb tuba in mind at some point in the process of getting this arrangement to the publisher, anyway it's a real part that does serve that purpose pretty well.

