A celeste tends not to work if you plant it next to the stop with which it's intended to beat. They tend to pull each other into tune. Therefore, you often find the celeste next to the diapason, so it may not beat properly. The problem wouldn't arise for Whitlock because he was used to Compton unit organs with the ranks planted separately. And Compton often provided a two-rank celeste, so the beat would be there already. When you can get a diapason that beats with the celeste, the effect can be ravishing.