A thible is a smooth stick used to stir broth or porridge.
In Chapter 9 of Wuthering Heights, Isabella is already regretting her recent marriage to Heathcliff as she prepares a pot of oatmeal:
It racked me to recall past happiness — and the greater peril there was of conjuring up its apparition, the quicker the thible ran round, and the faster the handfuls of meal fell into the water.
