The ingenuous youth of Owens in the writer’s time were not a particularly lamb-like lot, and occasional _émeutes_ were not unknown, but disturbances in Roscoe’s class-room were absolutely unheard of. Indeed, such was his personal ascendancy that at times his assistance was invoked to quell an uproar in a neighbouring territory. As he stepped into the room and began, “Now, boys, etc.,” he would be received with a round of cheers, and order would once more reign in Warsaw. A word of expostulation from him would suffice to ensure it. Of course, as the number of his pupils increased, and the laboratories became larger and more numerous, it became impossible to give so great a share of individual attention, and much had to be delegated to demonstrators, for the most part chosen from among senior students who were preparing for an academic career, and who had themselves been trained by him. At the same time he was quite alive to the value of “new blood,” and any promising young man who had shown aptitude for teaching or ability in research was sympathetically considered on the occasion of a vacancy. He next visited his private laboratory to consult with his assistants, and to learn how their work was progressing. As his engagements multiplied, and the calls upon his time increased, he gradually ceased to take any active part in the operations when assured of the competence of those to whom he had entrusted the execution of his plan of research. Indeed, he allowed his chosen helpers considerable latitude, if, as usually happened, they were genuinely interested in their work. He had a strong belief in the wisdom of giving the ’prentice hand “his head,” as the surest way of strengthening any latent faculty for original inquiry he might possess. He had himself been trained in this way, and he employed the same methods in turn. Roscoe, like Bunsen, set no very great value on lecture-room teaching, although he recognized that with the majority of students no other system is practicable. It no doubt serves to afford an _aperçu_ of the subject, which is what the average attendant at lectures presumably wants. At the same time he spared no pains to make his lectures interesting, and they were always admirably illustrated by experiments. Luckily he had in his _famulus_ Heywood, a remarkably able lecture-assistant, a skilful glass-blower, and a good mechanician, with a talent for devising striking and original illustrations. Roscoe had a good voice, clear enunciation, and a pleasant, easy mode of delivery, but he had none of the arts of the orator—nothing of the fiery, impulsive manner of his contemporary, Hofmann, or the command of polished speech that characterized Kekulé. In the lecture-room his language was simple and direct; he was an excellent expositor, always lucid, occasionally humorous, and never dull.