Mercury bulb on spirit thermometer?

I recently broke a Quickfit distillation thermometer and the bulb had liquid metal in it. I assumed it's mercury and acted accordingly. However, the column looks like spirit filled (blue liquid). Has anyone seen those, and if so, do you know if the metal is indeed mercury or something else? The model is Quickfit MF 31/2 (not MF 31/2S which is the newer one). I have never seen mercury and spirit combined in other thermometers. Just curious that's all.


[![Thermometer image](https://i.stack.imgur.com/NxeFG.jpg)](https://i.stack.imgur.com/NxeFG.jpg)


