Thank you for that Jed. Actually there is some osscillation there, but we chose to represent the data without it. There is a 'ripple' every 5 or 6 seconds. I'm afraid that the chances of our calorimetry being adrift* are slim to none. And slim just left town.
ETA * by more than 2.5% - we are looking at XSH in multiple joules, not millijoules. And we have done calibration every which way.