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.
When Livingstone returned from his first journey his acquaintance with Mr. Young was resumed, and their friendship continued through life. It is no slight testimony from one who knew him so long and so intimately, that, in his judgment, Livingstone was the best man he ever knew, had more than any other man of true filial trust in God, more of the spirit of Christ, more of integrity, purity, and simplicity of character, and of self-denying love for his fellow-men. Livingstone named after him a river which he supposed might be one of the sources of the Nile, and used ever to speak with great respect of the chief achievement of Mr. Young's life,--filling houses with a clear white light at a fraction of the cost of the smoky article which it displaced.
Beyond their own department, men of science are often as lax and illogical as any; but when scientific training is duly applied, it genders a habit of thorough accuracy, inasmuch as in scientific inquiry the slightest deviation from truth breeds endless mischief. Other influences had already disposed Livingstone to great exactness of statement, but along with these his scientific training may be held to have contributed to that dread of exaggeration and of all inaccuracy which was so marked a feature of his character through life.
It happened that Livingstone did not part company with Professor Graham and Mr. Young when he left Glasgow. The same year, Dr. Graham went to London as Professor in University College, and Livingstone, who also went to London, had the opportunity of paying occasional visits to his class. In this way, too, he became acquainted with the late Dr. George Wilson, afterward Professor of Technology in the University of Edinburgh, who was then acting as unsalaried assistant in Dr. Graham's laboratory. Frank, genial, and chivalrous, Wilson and Livingstone had much in common, and more in after-years, when Wilson, too, became an earnest Christian. In the simplicity and purity of their character, and in their devotion to science, not only for its own sake, but as a department of the kingdom of God, they were brothers indeed. Livingstone showed his friendship in after-years by collecting and transmitting to Wilson whatever he could find in Africa worthy of a place in the Edinburgh Museum of Science and Art, of which his friend was the first Director.
In the course of his second session in Glasgow (1837-38) Livingstone applied to the London Missionary Society, offering his services to them as a missionary. He had learned that that Society had for its sole object to send the gospel to the heathen; that it accepted missionaries from different Churches, and that it did not set up any particular form of Church, but left it to the converts to choose the form they considered most in accordance with the Word of God. This agreed with Livingstone's own notion of what a Missionary Society should do. He had already connected himself with the Independent communion, but this preference for it was founded chiefly on his greater regard for the _personnel_ of the body, and for the spirit in which it was administered, as compared with the Presbyterian Churches of Scotland. He had very strong views of the spirituality of the Church of Christ, and the need of a profound spiritual change as the only true basis of Christian life and character. He thought that the Presbyterian Churches were too lax in their communion, and particularly the Established Church. He was at this time a decided Voluntary, chiefly on the ground maintained by such men as Vinet, that the connection of Church and State was hurtful to the spirituality of the Church; and he had a particular abhorrence of what he called "geographical Christianity,"--which gave every man within a certain area a right to the sacraments. We shall see that in his later years Dr. Livingstone saw reason to modify some of these opinions; surveying the Evangelical Churches from the heart of Africa, he came to think that, established or non-established, they did not differ so very much from each other, and that there was much good and considerable evil in them all.