Arriving at Constantine on a Thursday we were delighted to find that by a happy chance we had come in the right week, almost on the right day to witness—if indeed we should be fortunate to gain admittance, a most difficult task we were told—the performances of that strange sect of fanatics, the Aïssa-Ouas, who held their mysterious séances only once a fortnight, on Fridays. […] we set out on the Friday night […] for the place of the orgies indicated to us by the landlord and which, having once entered the precincts of the native quarter, we had no difficulty in locating from the low, threatening tumult of voices, more like that of wild animals than of human beings, mixed with the noise of high-pitched drums and weird, monotonous chanting that reached our ears, increasing with every step that brought us nearer to it. We wondered what it could be like inside if already yards away we felt every nerve strangely excited At last, in a narrow, dirty little side street we came to some broad stone steps leading to what looked like a mosque […] As we entered we faced a large court, ending in a semicircle and surmounted by a high cupola from which was suspended a large, many-armed chandelier, whilst two candelabra stood between the columns on the line between the large court and the two adjoining smaller ones on the right and left. In the middle court there were crouching four old Arabs, each with a little drum between his knees and a small cauldron with glowing coals before him, over which, from time to time, they warmed the skin of the drum to keep it taut. Around those four, also sitting on the floor with their legs crossed, were from fifteen to twenty young men, all dressed in white and turbaned like the rest. It was from those the chanting noise we had heard in the street, emanated. They were “singing” at the top of their shrill voices passages from the Koran, paying no heed to time or pitch, every one as he listed, whilst the drums unceasingly and in perfect rhythm repeated the one phrase that approached anything like music […]

               Against the wall of the left aisle were leaning, in an upright position, shoulder to shoulder, and swaying to and fro like the pendulum of a clock, to the rhythm of the drums, a motley crowd of Arabs, Moors, Negroes from the Soudan, Bedouins, and Kabyles; every now and then the outer door would be thrown open and a new addition to the number of fanatics press his form between two links of the swaying human chain and join in the movement, desirous of becoming one of the elect, as will be seen presently. In the right aisle, under a sort of canopy, was sitting on an elevation a tall, silent, serious man of great age, with a long beard and in the beautifully draped, rich robe of a priest, two younger men, equally silent and serious, standing immovably beside him on the floor. At the feet of the priest there stood a mysterious-looking wooden chest with finely wrought brass corners. Louder and louder, quicker and quicker grew the noise of the drums and the chanting, and from the moving mass of the men on the wall of the left aisle, describing ever-larger half-circles with their bodies, there commenced to issue deep sighs and groans, ever increasing in frequency and force until the whole building resounded as with the agonized moans of souls in the torment of hell-fire, more terrifying almost than what was to come.