ghost was heard fiddling with the lock, but failed to enter. Another time he hid under the table and recognized the shoes of a ghost as the shoes he had sold the day before to Schrepfer's oldest marqueur. Schrepfer had once rather suspiciously refused to raise the spirit of the famous poet Christian Fürchtegott Gellert who had been known in person by some of the spectators. Among the techniques that Schrepfer reportedly used for his elaborate effects were actors performing as ghosts, ventriloquism, hidden speaking tubes, glass harmonica sounds, aromatic smoke, camera obscura projections, magic lantern projections on smoke, concave mirror projections and staged thunder. Schrepfer had been friends with pharmacist and Freemason Johann Heinrich Linck the Younger and regularly held lodge meetings in Linck's garden. Schrepfer even allowed Linck's wife into his lodge, while women were usually excluded from Freemason lodges. Linck was expelled from another lodge and probably told Schrepfer all he had learned there. Schrepfer needed materials that only a pharmacist could provide and Linck also knew a thing or two about optical and acoustic devices. A magic lantern and another type of projection box from his collection are now in the Museum Waldenburg. The projection box is decorated with a crucifix and a skull with wings. Conflicts with Masonic lodge Minerva Schrepfer had several conflicts with the Leipzig Freemason lodge "Minerva zu den drey Palmen" of the Order of Strict Observance, whose members he tried to recruit for his own lodge. There are some indications that Schrepfer was connected to the secret Rosicrucian Order of the Golden and Rosy Cross, that wanted to infiltrate Freemason lodges to weaken them from within. Schrepfer claimed support of the Jesuits to hide this connection and to win people for his own lodge. After many dismissed attempts Minerva allowed Schrepfer to speak at a meeting on January 15, 1773. With much aplomb he declared himself the true Freemason of knowledge and power in front of the gathering. Minerva's leaders pleaded to show more respect for their lodge, as they had heard that he had accused them of being impostors. They reminded Schrepfer that Minerva had the protection of Prince Karl von Sachsen, former Duke of Kurland and said they would make a case of it if they heard more accusations, and then they let him go. In the summer of 1783 Schrepfer reportedly entered a conference of the Minerva lodge