About this trick I was specially anxious, in order that I might practise some wanton jokes on my comrades. More particularly I formed a plan for keeping my ill-tempered mother-in-law in check by this means. I pretended that my object was merely to do good, and guard against evil. The preacher consented, but said at the same time, that on my part certain preparations were required. Three days in succession I was to feast, and every day to say some _Ichudim_. These are Cabbalistic forms of prayer, whose occult meaning aims at producing in the intellectual world sexual unions, through means of which certain results are to be brought about in the physical. I did everything with pleasure, made the conjuration which he had taught me, and believed with all confidence that I was now invisible. At once I hurried to the _Beth Hamidrash_, the Jewish academy, went up to one of my comrades, and gave him a vigorous box on the ear. He however was no coward, and returned the blow with interest. I started back in astonishment; I could not understand how he had been able to discover me, as I had observed with the utmost accuracy the instructions of the preacher. Still I thought I might, perhaps, unwittingly and unintentionally have neglected something. I resolved, therefore, to undertake the operation anew. This time, however, I was not going to venture on the test of a box on the ear; I went into the academy merely to watch my comrades as a spectator. As soon as I entered, however, one of them came up to me, and showed me a difficult passage in the Talmud, which he wished me to explain. I stood utterly confounded, and disconsolate over the failure of my hopes. Thereupon I went to the preacher, and informed him of my unsuccessful attempt. Without blushing, he replied quite boldly, "If you have observed all my instructions, I cannot explain this otherwise than by supposing that you are unfit for being thus divested of the visibility of your body." With great grief, therefore, I was obliged to give up entirely the hope of making myself invisible. This disappointed hope was followed by a new delusion. In the preface to the _Book of Raphael_, which the angel of that name is said to have delivered to our first father Adam at his banishment from paradise, I found the promise, that whoever keeps the book in his house is thereby insured against fire. It was not long, however, before a conflagration broke out in the neighbourhood, when the fire seized my house too, and the angel Raphael himself had to go up into heaven in this chariot of fire.