A double knock at the street door stops my pen suddenly. I make no complaint, for I have been, to my own amazement, filling these pages for the last three hours, in my parlour after dinner, without interruption. A well-known voice in the passage smites my ear, inquiring for me, on very particular business, and asking the servant to take in the name. The servant appears at my door, and I make up my mind to send these leaves to the printer, unfinished as they are. No necessity, Susan, to mention the name; I have recognised the voice. This is my friend who does not at all like the state of my health. He comes, I know beforehand, with the address of a new doctor, or the recipe of a new remedy; and he will stay for hours, persuading me that I am in a bad way. No escaping from him, as I know by experience. Well, well, I have made my confession, and eased my mind. Let my friend who doesn't like the state of my health, end the list, for the present, of the dear friends whom I could dispense with. Show him in, Susan--show him in. CASES WORTH LOOKING AT.--III. THE CAULDRON OF OIL. About one French league distant from the city of Toulouse, there is a village called Croix-Daurade. In the military history of England, this place is associated with a famous charge of the eighteenth hussars, which united two separated columns of the British army, on the day before the Duke of Wellington fought the battle of Toulouse. In the criminal history of France, the village is memorable as the scene of a daring crime, which was discovered and punished under circumstances sufficiently remarkable to merit preservation in the form of a plain narrative. I. THE PERSONS OF THE DRAMA. In the year seventeen hundred, the resident priest of the village of Croix-Daurade was Monsieur Pierre-Célestin Chaubard. He was a man of no extraordinary energy or capacity, simple in his habits, and sociable in his disposition. His character was irreproachable; he was strictly conscientious in the performance of his duties; and he was universally respected and beloved by all his parishioners. Among the members of his flock, there was a family named Siadoux. The head of the household, Saturnin Siadoux, had been long established in business at Croix-Daurade as an oil-manufacturer. At the period of the events now to be narrated, he had attained the age of sixty, and was a widower. His family consisted of five children--three young men, who helped him in the business, and two daughters. His nearest living relative was his sister, the widow Mirailhe.