Outdoor exercise brought little relief from the eternal solitude; it was only taken every other day, and lasted a very short while. The time allowed was but a quarter of an hour, including dressing and undressing, my own clothes being brought to me for these occasions. My walks took place in a yard enclosed with high walls, where no one was to be seen but gendarmes and sentries. The slightest attempt to converse with them was forbidden, or even that they should answer the simplest question. If one asked anything they stared straight in one’s face and were dumb. After some days, however, an occupation provided itself; I became aware of a gentle knocking, perceptible at a slight distance from the wall. When I was in prison before I had learned to use this means of communication with my fellow-captives, and the alphabetical code at once came back to me.[23] Footnote 23: The letters of the alphabet being arranged in certain groups, _e.g._:— a b c d e f g h i k l m n o p r s t u v w x y z, words are made up by knocking so many times on the wall for each letter. First the horizontal line in which the letter stands is counted, and then its number in the line. For example, to make the word “you” one would knock as follows: four taps, a short pause, five taps, a longer pause; three taps, a short pause, two taps, longer pause; four taps, short pause, one tap. The taps are not only heard in the neighbouring cell, but sometimes in far-distant ones if they have a common wall. It is difficult to describe my joy when I heard the familiar sounds, and supposed they must be addressed to myself, but I was soon undeceived. I began to knock back, but found out at once that the signals were not meant for me; two friends were having conversation, and they would not answer my attempts to introduce myself. This knocking was strictly forbidden, and they hesitated to admit an unknown person to their company, fearing to be entrapped, and deprived of further intercourse. I was obliged to content myself with making out what these two said to each other in their short conversations, but it was only stereotyped, often-recurring phrases: “Good morning,” “How have you slept?” “What are you doing?” and the answers: “Well,” “Drinking tea,” etc. I envied them the exchange of such insignificant speeches. I never discovered whether they were two men or two women, or a man and a woman.