His collection of instruments, which subsequently passed into the possession of the University, and is at present used by me as his successor, is the most eloquent testimony of this. Everything is in the most perfect order: if a silk-thread, a glass tube, or a cork, are required for an experiment, one may safely depend on finding them near the instrument. All the apparatus which he contrived is made with the best means at his disposal, without sparing either material, or the labour of the workman, so as to ensure the success of the experiment, and by making it on a sufficiently large scale to render it visible as far off as possible. I recollect very well with what wonder and admiration we students saw him experiment, not merely because all the experiments were successful and brilliant, but because they scarcely seemed to occupy or to disturb his thoughts. The easy and clear flow of his discourse went on without interruption; each experiment came in its right place, was performed quickly, without haste or hesitation, and was then put aside. I have already mentioned that the valuable collection of apparatus came into the possession of the University during his lifetime. He specially wished that what he had collected and constructed as appliances in his scientific work should not be scattered and estranged from the original purpose to which he had devoted his life. With this feeling he bequeathed to the University the rest of the apparatus of his laboratory, as well as his very rich and valuable library, and he thus laid the foundation for the further development of a Public Physical Institute. It is sufficient in these few touches to have recalled the mental individuality of our departed friend, so far as the sources of the direction of his activity are to be found. Personal recollections will furnish a livelier image to all those of you who have worked with him for the last thirty years. If we now proceed to discuss the results of his researches it will not be sufficient to read through and to estimate his academical writings. I have already shown that a prominent part of his activity was directed to his fellow-creatures. To this must be added, that he lived in an age when natural science passed through a process of development, with a rapidity such as never occurred before in the history of science. But the men who belonged to such a time, and co-operated in this development are apt to appear in wrong perspective to their successors, since the best part of their work seems to the latter self-evident, and scarcely worthy of mention.