His chief work in Glasgow was the prosecution of medical study. Of his teachers, two attracted him beyond the rest--the late Dr. Thomas Graham, the very distinguished Professor of Chemistry, and Dr. Andrew Buchanan, Professor of the Institutes of Medicine, his life-long and much-attached friend. While attending Dr. Graham's class he was brought into frequent contact with the assistant to the Professor, Mr. James Young. Originally bred to a mechanical employment, this young man had attended the evening course of Dr. Graham, and having attracted his attention, and done various pieces of work for him, he became his assistant. The students used to gather round him, and several met in his room, where there was a bench, a turning-lathe, and other conveniences for mechanical work. Livingstone took an interest in the turning-lathe, and increased his knowledge of tools--a knowledge which proved of the highest service to him when--as he used to say all missionaries should be ready to do--he had to become a Jack-of-all-trades in Africa. Livingstone was not the only man of mark who frequented that room, and got lessons from Mr. Young "how to use his hands." The Right Hon. Lyon Playfair, who has had so distinguished a scientific career, was another of its habitués. A galvanic battery constructed by two young men on a new principle, under Mr. Young's instructions, became an object of great attraction, and among those who came to see it and its effects were two sons of the Professor of Mathematics in the University. Although but boys, both were fired at this interview with enthusiasm for electric science. Both have been for many years Professors in the University of Glasgow. The elder, Professor James Thomson, is well known for his useful inventions and ingenious papers on many branches of science. The younger, Sir William Thomson, ranks over the world as prince of electricians, and second to no living man in scientific reputation. Dr. Graham's assistant devoted himself to practical chemistry, and made for himself a brilliant name by the purification of petroleum, adapting it for use in private houses, and by the manufacture of paraffin and paraffin-oil. Few men have made the art to which they devoted themselves more subservient to the use of man than he whom Livingstone first knew as Graham's assistant, and afterward used to call playfully "Sir Paraffin." "I have been obliged to knight him," he used to say, "to distinguish him from the other Young." The "other" Young was Mr. E. D. Young, of the Search Expedition, and subsequently the very successful leader of the Scotch Mission at Lake Nyassa. The assistant to Dr. Graham still survives, and is well known as Mr. Young, of Kelly, LL.D. and F.R.S.