He frowned at the attempted greeting. The condition of the thing seemed to deteriorate more and more; its cylinders required regular replacement, and preparing them could be tedious. It was possible that the student who had been directed to replace it the previous week had botched the job, but unlikely... it wasn't that difficult, and they were bright.

L turned his head to Temeraire. "Have you established anything yet? It shouldn't require replacement as quickly as this. The first thing to do is to remove this plate here on the back."