To speak of authorities, what comparison is there between these great scientists and discoverers, and those who are satisfied with the general assurance that “any one who has grasped the elements of natural sciences must become a monist,” and “that the supernatural exists only in the brain of the visionary and ignorant,” that, “in the same measure in which the victorious progress of modern knowledge of nature surpasses the scientific achievements of former centuries, the untenableness of all mystical views of life that tend to harness the reason in the yoke of so-called revelation has been made clear” (_Haeckel_), and who in such assurance find perfect intellectual gratification. They recall an incident at the Congress of English natural scientists, held at Belfast in 1874, when _Tyndall_ delivered from the platform a materialistic lecture, and among the audience sat _Maxwell_, his superior in scientific research, who put down the lecture in doggerel rhyme, in a humorous vein, of course, but not without deserved sarcasm. We proceed on our way, trying to make haste, and omitting many names that might be mentioned, limiting ourselves to the most prominent ones. Among the chemists we name _Lavoisier_. A martyr to his science, he died under the guillotine of the Revolution in 1794; he had remained true to his Christian faith. The Swede, _J. Berzelius_ (died 1848), openly professed his belief in God. _Thénard_ (died 1859), the discoverer of boron, of a blue dye named after him, and of many other chemicals, was a staunch Catholic. The pastor of St. Sulpice could testify at his funeral as follows: “He attended church every Sunday, eyes and heart fixed on his prayer-book, and on solemn Feast days he received Holy Communion.... With _Baron Thénard_ one of the greatest benefactors of my poor people is gone” (_Kneller_). _Dumas_ (died 1884), who is esteemed by his pupil _Pasteur_ as the peer of _Lavoisier_, was also a practical Catholic, as was his compatriot _Chevreul_ (died 1889). This great man had the rare good fortune to be present at his own centenary in 1886. At this great celebration he received an address by the Berlin Academy, stating that his name had a prominent place on the list of the great scientists who had carried the scientific repute of France to all quarters of the globe. When, in view of the mundane character of the celebration, the liberal press endeavoured to rank him among the representatives of unbelieving science, and this question being discussed in public, _Chevreul_ felt himself constrained to proclaim his religious persuasion openly in a letter to _Count de Montravel_, in which he said: “I am simply a scientist, but those who know me, know also that I was born a Catholic, that I lead a Catholic life, and that I want to die a Catholic” (Civilta Cattolica, 1891, 292). Two Germans may conclude the list of chemists, _Schoenbein_ (died 1868) and _J. Liebig_ (died 1873).