One day Casanova asked the gaoler to buy him the works of Maffei; but as that worthy profited by any surplus of the daily allowance that might be in hand at the end of the month, Laurent was terribly averse to extraordinary expenses, and suggested that other people in the prison had books and that they might advantageously lend them to each other. A system of regular exchange now began, and a correspondence was started by means of the hollow backs of the vellum-bound books, which lay flat when the books were closed, but formed a kind of pocket when opened. Letters passed back and forth between the tenants of neighbouring cells. Casanova found that overhead were two occupants, one Father Balbi, a monk of noble Venetian family, and the other an aged man, Count Aschino of Udine. Casanova’s pen was the long nail of his little finger trimmed to a point and dipped into mulberry juice; the fly leaves of the books themselves supplied the paper. The subject discussed was eternally the same,--that of their escape; but the mind of the reverend Father Balbi was more critical than inventive, and Casanova felt that they could not work again for awhile. Nevertheless, he informed the monk of the existence of his precious crowbar, and offered to convey it to him if he would consent to use it in making an opening through the ceiling of his own cell into the garret above and then cutting his way through the floor to reach Casanova, who would answer for the rest of the operation. Certainly he had formed no high opinion of the discretion and skill of his new ally, but realised that he must work with such tools as he had at hand. Balbi’s first step was to provide himself with a large number of pictures of saints to cover up and conceal the damaged ceiling and floor. The next difficulty was to pass the working tool safely from one cell to the other. The fur-lined dressing gown was first thought of as a vehicle, but was abandoned. At last, after severe cogitation, an astute plan was devised. Casanova begged the gaoler to buy him a new folio edition of the Vulgate, just published, and the volume was procured in the hopes that the crowbar might be concealed in the back of the binding. But it was two inches too long and the ends protruded!