What calls/stores DBMS_JOB calls?

I have a DBMS_JOB submitted every hour (yes, part of the syntax of the call).  I'm looking to change the interval that it is called, but can't locate where that is done.

The call:

declare number;

begin

dbms_job.submit(j.'<PROCEDURE_NAME>;',sysdate,'sysdate + 1/24');

end;

/

What reads this every hour?  (I understand that "1/24" goes to "1" if I want it to run daily.  Just not sure where to set that (and how to keep this from running once an hour when I do).

Mike