Heroes of science

by P. Martin Duncan

Aristoteles, Strabo, and Plinius wrote about the changes which were progressing on the surface of the earth, and compared them, in their reasoning, with changes they presumed had been, but still no great advance was made.

In the early part of the sixteenth century a remarkable discussion sprang up about the nature of shells and bones, which were found in layers of earth remote from the sea. The celebrated painter Leonardo da Vinci had seen some of these fossils during his youth, when he planned and carried out some important canals in the north of Italy. He laughed at the fancies of the day about the shells, for some people said that they were made by the stars, and others that they were brought forth naturally, in the layers of earth in which they were found. He wanted to know where the things were being made in the hills, by the stars, at the present time, and stated that, like the rounded stones of gravel, the shells had been in the sea, and that they were of different ages and kinds, and were once alive. But the former living condition of fossils, and the possibility of their being understood, by comparing them with recent or living things, was, perhaps, most strongly put by Steno, a Dane.

In 1638, a goldsmith, Steno by name, living at Copenhagen, who was a tradesman of the King Christian IV. of Denmark, had a son. The young Nicholas was brought up carefully, evidently was well educated, and was destined for the medical profession. A strict Lutheran, he naturally went to Holland for a part of his education, and studied at Leyden under the very distinguished anatomists there, after he had taken his degree. Nothing is known about his person or habits, but the results of his constant labour prove him to have been a most industrious student, and also an investigator of the human frame in his early days of manhood. At first the medical profession was everything to him, and he studied human anatomy and physiology with great success, making some important and interesting discoveries. He discovered the duct or channel by which the saliva runs into the mouth from the salivary gland beneath the skin on the cheek, and in 1664 he published some researches on the manner in which the chick is nourished in the egg. Moreover, he examined the structures of the eye of the calf, the nature of the mucous secretion, and wrote on the heart. While engaged in these researches at Amsterdam, he heard of the death of his mother, and returned to Copenhagen. After a short stay there, he set out for Italy, taking France on his way; and he began a series of researches on the structure of the brain at Paris in 1664. Here a great change occurred, which influenced his future life in a remarkable degree. Steno, well known then as a successful investigator, came under the notice of a great French geographer, Thévenot, and, what was more important, became the friend of Bossuet, one of the greatest preachers and teachers the Roman Catholic Church has ever produced. Steno was so influenced by Bossuet, that he became converted to the Roman Catholic faith, and left the Lutheran Church. Going subsequently into Italy, Steno pursued his studies, and settled in Florence, in 1667, being well received by the Grand Duke Ferdinand II. de Medici. In spite of the somewhat natural jealousy of the medical men of the city, Steno was appointed physician to the Grand Duke, and prosecuted his anatomical studies under his influence. Then he came across a subject which directed his attention to geology, or rather to that part of the science which relates to extinct animals. In a letter to Thévenot, Steno describes the dissection of a shark which had been captured off Leghorn in 1666, and especially discussed the mode of growth of the teeth of the animal. At this time many fossils were picked up and gathered out of layers or strata, which were called by many curious names, and believed to be anything but what they really were. They were distinguished by Steno at once as shark’s teeth, and he insisted that sharks lived during the former ages of the globe, and that they had become entombed in the deposits which were then forming a stratum or layer of earth, the result of deposition in water, being the burial-ground of the time of its collection or formation.

Fossils were thus shown by Steno to be mineralized or petrified organic remains, and he gave the hint or method to future investigators, that the example of the existing animals must be taken, in order to learn the nature of those creatures whose remains are more or less perfectly preserved in the fossil condition.

Following out this subject, Steno wrote on the manner in which deposits accumulate, and accumulated in past ages; and he concluded that if we found a deposit containing sea-salt and the remains of marine animals, planks of ships etc., we should believe that the sea had once been there, whether the bed was exposed in consequence of the sea having retired, or because the land had been raised. He showed that although the lowest beds deposited over any area, must conform to the shape of the underlying rock, the tendency of all sediment must be to occupy the horizontal position; and so when we find them highly inclined, as in mountains, for instance, we must refer this to subsequent movement. He noticed that mountains are made up both of horizontal and inclined strata, as may be seen along their flanks. He infers that mountains were once not in existence, and that they do not grow, but that their regions are raised and depressed and subject to rending and fissuring. Steno clearly showed that the land had sunk and had been again elevated in the geological ages, and in considering the causes he seems to have grasped the idea that the internal heat of the earth becoming less, the mass cools, and that the movements on the surface have had to do with the cooling. His most important work was removing fossils out of the category of marvels, sports of nature, and as things which grew in the earth, to the proper truth that they are preserved parts of animals and plants which were formerly alive. In 1688, Steno was appointed to the chair of anatomy at Copenhagen; but he had to suffer from jealousy, and doubtless some religious persecution influenced his desire to leave his native country and to return to Florence again. This he did, and Cosmo III. entrusted him with the education of his son. Steno then began to give up science and to study theology, and wrote several works on the subject by which he hoped to convert his old natural history friends. One of these involved him in a controversy with the reformed clergy of Jena. The Pope, Innocent XI., rewarded Steno in 1677, by making him a bishop and apostolic vicar of Northern Europe. Steno went to reside at Hanover; but he had to leave, and returning to Schwerin, he died there. His body was, at the request of the Grand Duke Cosmo, carried back to Tuscany in 1687.

CHAPTER X.
THE LIFE OF HUTTON.

The rise of the modern school of geology—The continuity of the operations of nature and their sameness—The necessity of studying the existing state of things in order to comprehend the past—The denial of catastrophes—Hutton’s theory of the earth the foundation of scientific geology.