It is often asserted that geology was one of the sciences that was distinctly opposed by churchmen; yet we shall see that the father of modern geology, one of the greatest anatomists of his time, was not only a convert to Catholicity, but became a clergyman about the time he was writing the little book that laid the foundation of modern geology. We shall see, too, that, far from religion and science clashing in him, he afterwards was made a bishop, in the hope that he should be able to go back to his native land and induce others to become members of that Church wherein he had found peace and happiness. In the modern times biology has been supposed to be the special subject of opposition, or at least fear, on the part of ecclesiastical authorities. It is for this reason that the life of Abbot Mendel has been introduced. While working in {11} his monastery garden in the little town of Brünn in Moravia, this Augustinian monk discovered certain precious laws of heredity that are considered by progressive twentieth-century scientists to be the most important contributions to the difficult problems relating to inheritance in biology that have been made. These constitute the reasons for this little book on Catholic clergymen scientists. It is published, not with any ulterior motives, but simply to impress certain details of truth in the history of science that have been neglected in recent years and, by presenting sympathetic lives of great clergymen scientists, to show that not only is there no essential opposition between science and religion, but on the contrary that the quiet peace of the cloister and of a religious life have often contributed not a little to that precious placidity of mind which seems to be so necessary for the discovery of great, new scientific truths. {12} II. COPERNICUS AND HIS TIMES. {13} All the vast and most progressive systems that human wisdom has brought forth as substitutes for religion, have never succeeded in interesting any but the learned, the ambitious, or at most the prosperous and happy. But the great majority of mankind can never come under these categories. The great majority of men are suffering, and suffering from moral as well as physical evils. Man's first bread is grief, and his first want is consolation. Now which of these systems has ever consoled an afflicted heart, or repeopled a lonely one? Which of these teachers has ever shown men how to wipe away a tear? Christianity alone has from the beginning promised to console man in the sorrows incidental to life by purifying the inclinations of his heart, and she alone has kept her promise.--MONTALEMBERT, Introduction to _Life of St. Elizabeth_. {14} [Illustration: NICOLAO COPERNICO] {15} II. COPERNICUS AND HIS TIMES.