Hiding in a quiet spot, the two friends began working at the philosopher's stone, that is, at converting copper into silver and gold. Chasteuil had some experience of alchemy, and fancied he was master of the famous secret. Full of gratitude for the service done him, he gave Vanens the secret so far as silver was concerned, but would tell him nothing about the gold, 'not thinking Vanens prudent enough for that.' Shortly afterwards we find Chasteuil in the service of the Duke of Savoy, captain of the guards of the White Cross, and--extraordinary fact--tutor to his son! While occupied with the education of the young Prince of Piedmont, Chasteuil continued his 'philosophy,' and discovered an oil, which, as he appeared convinced himself, would turn metals into gold. He also wrote translations of authors sacred and profane--the minor prophets, Petronius, the Thebaïd of Statius; and he dabbled in poetry. He had just passed his fortieth year. A contemporary gives us his portrait: 'Middle height, very thin, always troubled with a nasty cough caused by a wound he received in the body, round-shouldered, slightly crooked, with a wry mouth, scanty beard, hair black and flat, complexion swarthy and sallow.' Moréri adds: 'Monsieur de Chasteuil was one of the most accomplished of gentlemen, and a perfect master of the platonic philosophy.' Vanens and Chasteuil struck up an alliance with Robert de Bachimont, lord of La Miré, who had married a cousin of Superintendent Fouquet. Bachimont had at Paris a house near the Temple, with four smelting furnaces: a large one on the third floor, two smaller ones in an ante-room, and a large one in the cellar. He also had apartments at Compiègne in the _Ecu de France_, where there was nothing but crucibles, alembics, vessels of glass and of earthenware, cucurbits, philosophical stoves open and closed, grates and mortars, retorts and matrasses, sal-ammoniac and iron filings, and a thousand varieties of powders, pastes, and liquids. Finally, he had another establishment at the abbey of Ainay, near Lyons, completely fitted up for the fusion of metals, the distillation of herbs, and other practices of alchemy. Before long the association was enlarged by the addition of a person of some importance, Louis de Vasconcelos y Souza, Count of Castelmelhor, who had been practically the governor of Portugal for five or six years as the favourite of King Alfonso VI. Bachimont says that Castelmelhor taught him the secret of colouring glass red. After the death of the Duke of Savoy on June 12, 1675, Castelmelhor withdrew to England, where he gained the favour of Charles II., an ardent alchemist and astrologer. He was present at the death of the English king, and it was he that brought in the Catholic priest who gave him extreme unction.