But their greatest reliance was placed in the use of dynamite. This highly explosive material was regarded as the chief arm of their cause. For many weeks, the leaders had experimented with it. Some six weeks before the disastrous Haymarket riot, Louis Lingg had brought a bomb to the house of William Seliger, No. 442 Sedgwick Street, where he boarded, and announced his intention of making other bombs like it. Before this he had provided himself with dynamite, the money for its purchase having been realized at a ball given some time previously and turned over to him to use in experiments. Being out of employment at the time, he devoted himself energetically to experiments with that material, and produced large gas-pipe bombs. One of these he took out to a grove north of the city, and, placing it in the crotch of a tree, exploded it, splitting the tree to pieces. The result of the test appears to have been satisfactory, and he next gave his attention to the manufacture of globular shells. In the casting of these he used the kitchen stove to melt his metal, and often received the assistance of Seliger, Thielen and Hermann. All day Tuesday, May 4, he worked most persistently and seemed in a great hurry to make as many bombs as possible. He was helped on that day by the parties named and two others, Hueber and Munzenberger. Before the close of the day they had finished over a hundred bombs. While they were at work Lehman visited them and carried home a satchel of dynamite, which he subsequently, after the Haymarket riot, buried out on the prairie, and which was afterwards disinterred by the police. Not alone did he and his friends experiment with dynamite, but it appears that Spies, Parsons, Fischer, Fielden and Schwab also tried their hands at it and handled the deadly stuff at the office of the _Arbeiter-Zeitung_. They had several bombs there and made no secret of the purpose for which they intended them. The office was afterwards discovered to be an arsenal of revolvers and dynamite.