From Ash Street the countess took me to Glasnevin Cemetery, where men lie buried, who, having lived under conditions such as I had just looked upon, spent their lives in protest against the same. Here was the grave of O'Donovan Rossa and a score of others whom I felt were heroes. Here, also, was the grave of Anne Devlin, that brave woman who refused to betray Robert Emmet to the British officers seeking him after his unsuccessful effort to oppose English rule in 1803. These graves and the ruinous houses of Ash Street show patriotism and poverty working for each other and, despite themselves, against each other. A few months after my visit, there was fighting all about Glasnevin Cemetery between the Royal Irish Constabulary and those who were to carry on the traditions of the great struggle. Not far from the home of Countess Markievicz stand the Portobello barracks, while much farther off are the Beggar's Bush barracks. She asked me one day if I thought I could make a plan of the latter from observation that would be of use if at any time it was decided to dynamite them. She gave no explanation, did not even tell me in what part of Dublin the barracks were located nor that two officers of the Irish Volunteers had already tried to make this plan and had failed. But she knew that I had had experience in gaging distances and drawing maps. I had just taken a course in calculus, and it was when telling her of my love for mathematics that she set me this task. There was a large map of Dublin on the wall of a study in her house. I scrutinized this carefully, for I did not know my way alone about Dublin. Then I started out and found the place without great difficulty. It is in the southwestern outskirts of the city, a large, brick structure filling in the right angle where two streets meet. From this corner I walked very slowly along the front of the barracks, counting my paces, gaging the height of the outer wall, and studying the building itself for anything its secretive exterior might betray. I presently noticed that the loopholes which appeared in the wall at regular intervals stopped short a number of yards from the corner. They had been filled in with bricks of a slightly different color than the rest of the wall. At once I asked myself why this had been done and, to discover the reason, if possible, crossed the street to where I could look over the wall. I was able to see that within the right angle at the corner was a small, circular building. It stood close to both the front and side wall, yet did not touch either. There was room for a sentry to walk around it, and all loopholes near it had been bricked up. The conclusion I drew from this fact was that here was a powder magazine. It was so placed as not to be too noticeable from the street, easily guarded by a sentry, and conveniently near the loopholes in case defense of the barracks became necessary.