It was during these years in Italy that Stensen did what must be considered, undoubtedly, his most important work, even more important, if possible, than his anatomical discoveries. This was his foundation of the science of geology. As has been well said in a prominent text-book of geology, his book on this subject sets him in that group of men who as prophets of science often run far ahead of their times to point out the path which later centuries will follow in the road of knowledge. It is rather surprising to find that the seventeenth century must enjoy the privilege of being considered the cradle of geological knowledge. There is no doubt, however, that the great principles of the science were laid down in Stensen's little book, which he intended only to be an introduction to a more extensive work, but the latter was unfortunately never completed, nor, indeed, so far as we are able to decide now, ever seriously begun.
One of the basic principles of the science of geology Stensen taught as follows: "If a given body of definite form, produced according to the laws of nature, be carefully examined, it will show in itself the place and manner of its origin." This principle he showed would apply so comprehensively that the existence of many things, hitherto apparently inexplicable, became rather easy of solution. It must not be forgotten that before this time two explanations for the existence of peculiar bodies, or of ordinary bodies, in peculiar places, had been offered. According to one school of thought, the fossils found deep in the earth, or sometimes in the midst of rocks, had been created there. It was as if the creative force had run beyond the ordinary bounds of nature and had produced certain things, ordinarily associated with life, even in the midst of dead matter. The other explanation suggested was that the flood had in its work of destruction upon earth caused many anomalous displacements of living things, and had buried some of the animals under such circumstances that later they were found even beneath rocks, or deep down in the earth, far beyond where the animals could be supposed to have penetrated by any ordinary means during life.
Stensen had observed very faithfully the various strata that are to be found wherever special appearances of the earth's surface were exposed, or wherever deep excavations were made. His explanation of how these various strata are formed will serve to show, perhaps better than anything else, how far advanced he was in his realization of ideas that are supposed to belong only to modern geology. He said: "The powdery layers of the earth's surface must necessarily at some time have been held in suspension in water, from which they were precipitated by their own weight. The movement of the fluid scattered the precipitate here and there and gave to it a level surface."
"Bodies of considerable circumference," Stensen continues, "which are found in the various layers of the earth, followed the laws of gravity as regards their position and their relations to one another. The powdery material of the earth's strata took on so completely the form of the bodies which it surrounded that even the smallest apertures became filled up and the powdery layer fitted accurately to the surface of the object and even took something of its polish."
With regard to the composition of the various strata of the earth, the father of geology considered that if in a layer of rock all the portions are of the same kind there is no reason to deny that such a layer came into existence at the time of creation, when the whole surface of the earth was covered with fluid. If, however, in any one stratum portions of another stratum are found, or if the remains of plants or animals occur, there is no doubt that such a stratum had not its origin at the time of creation, but came into existence later.
If there is to be found in a stratum traces of sea salt, or the remains of sea animals, or portions of vessels, or such like objects, which are only to be encountered at the bottom of the sea, then it must be considered that this portion of the earth's surface once was below the sea level, though it may happen that this occurred only by the accident of a flood of some kind. The great distance from the sea, or other body of water, at the present time, may be due to the sinking of the water level in the neighborhood, or by the rising up of a mountain from some internal terrestrial cause in the interval of time. He continues:–
If one finds in any layer remains of branches of trees, or herbs, then it is only right to conclude that these objects were brought together because of flood or of some such condition in the place where they are now found. If in a layer coal and ashes and burnt clay or other scorched bodies are found, then it seems sure that some place in the neighborhood of a watercourse a fire took place, and this is all the more sure when the whole layer consists of ashes and coal. Whenever in the same place the material of which all the layers is composed is the same, there seems to be no doubt that the fluid to which the stratum owes its origin did not at different times obtain different material for its building purposes.
In respect to the mountains and their formation, Stensen said very definitely:–
All the mountains which we see now have not existed from the beginning of things. Mountains do not, however, grow as do plants. The stones of which mountains are composed have only a certain analogy with the bones of animals, but have no similarity in structure or in origin, nor have they the same function and purpose. Mountain ranges, or chains of mountains as some prefer to call them, do not always run in certain directions, though this has sometimes been claimed. Such claims correspond neither to reason nor to observation. Mountains may be very much disturbed in the course of years. Mountain peaks rise and fall somewhat. Chasms open and shut here and there in them, and though there are those who pretend that it is only the credulous who will accept the stories of such happenings, there is no doubt that they have been established on trustworthy evidence.
In the course of his observations in Italy, Stensen had seen many mussel shells, which had been gathered from various layers of the earth's surface. With regard to the shells themselves, he said that there could be no doubt that they had come as the excretion of the mantle of the mussel, and that the differences that could be noted in them were in accordance with the varying forms of these animals. He pointed out, however, that some of the mussel shells found in strata of rock were really mussel shells in every respect as regards the material of which they were composed as well as their interior structure and their external form, so that there could be no possible question of their origin. On the other hand, a certain number of the so-called mussel shells were not composed of the ordinary materials of which such shells are usually made up; but had indeed only the external form of genuine shells. Stensen considered, however, that even these must be regarded as originating in real mussel shells, the original substance having been later on replaced by other material. He explained this replacement process in very much the same way that we now suggest the explanation of various processes of petrification. There is no doubt that in this he went far beyond his contemporaries, and pointed out very clearly what was to be the teaching of generations long after his own.
The same principles he applied to mussel shells, Stensen considered must have their application also to all other portions of animal bodies, teeth, bones, whole skeletons, and even more perishable animal materials that might be found buried in the earth's strata. His treatment of the question of the remains of plants was quite as satisfactory as that of the animals. He distinguished between the impressions of plants, the petrification of plants, the carbonization of plants, and then dwelt somewhat on the tendency of certain minerals to form dendrites, that is, branching processes which look not unlike plants. He pointed out how easy it is to be deceived by these appearances, and stated very clearly the distinction between real plants and such simulated ones.
It will be scarcely necessary for us to apologize for having given so much space to Stensen's work on geology. Many distinguished scientists, however, have insisted that no greater advance at the birth of a science was ever made than that which Stensen accomplished in his geological work. Hoffman says that after carefully studying the work, he has come to the conclusion that of the successors of Stensen, no student of the mountains down to Werner's day had succeeded in comprehending so many fruitful points of view in geology. None of his great successors in geology has succeeded in introducing so many new ideas into the science as the first great observer. For several centuries most of his successors in geology remained far behind him in creative genius, and so there is little progress worth while noting in the knowledge of the method of earth formation, until almost the beginning of the nineteenth century, though his little book was written in 1668 and 1669.
Leibnitz regretted very much that Stensen did not complete his work on geology as he originally intended. Had he succeeded in gathering together all of his original observations, illustrated by the material he had collected, his work would have had much greater effect. As it was, the golden truth which he had expressed in such few words, without being able always to state just how he had come to his conclusions, was only of avail to science in a limited way. Men had to repeat his observations long years afterwards in order to realize the truth of what he had laid down. Leibnitz considered that it took more than a century for geological science to reach the point at which it had been left by Steno's work, and which he had reached at a single bound. There is scarcely a single modern geologist interested at all in the history of the science who has not paid a worthy tribute to Steno's great basic discoveries in the science. It was not a matter for surprise, then, that the International Congress of Geologists which met at Bologna in 1881 assembled at his tomb in Florence in order to do him honor, after the regular sessions of the Congress had closed. They erected to his memory a tablet with the following scription:
"Nicolae Stenonis imaginem vides hospes quam aere collato docti amplius mille ex universo terrarum orbe insculpendam curarunt in memoriam ejus diei IV cal. Octobr. an. MDCCCLXXXI quo geologi post conventum Bononiae habitum praeside Joanne Capellinio equite hue peregrinati sunt atque adstantibus legatis flor Municipii et R. Instituti Altiorum doctrinarum cineres viri inter geologos et anatomicos praestantissimi in hujus templi hypogaeo laurea corona honoris gratique animi ergo honestaverunt."11
Stensen's work brought him in contact with some of the distinguished men of the seventeenth century, all of whom learned to appreciate his breadth of intelligence and acuity of judgment. We have already mentioned his epistolary relation with Spinoza, and have said something about the controversy with Leibnitz, into which, in spite of his disinclination to controversy generally, he was drawn by the circumstances of the time and the solicitation of friends. Another great thinker of the century with whom he was brought into intimate relationship was Des Cartes, the distinguished philosopher. In fact, Des Cartes's system of thought influenced Stensen not a little, and he felt, when describing the function of muscles in the human body, and especially when he demonstrated that the heart was a muscle, that the mechanical notions he was thus introducing into anatomy were likely to prove confirmatory of Des Cartes's philosophic speculations. Almost more than any other, Stensen was the father of many ideas that have since become common, with regard to the physics of the human body and its qualities as a machine.
With his breadth of view, from familiarity with the progress of science generally in his time, Steno's discussions of the reason for the lack of exact knowledge and for the prevalence of error, in spite of enthusiastic investigation, are worth while appreciating. He considered that the reason why so many portions of natural science are still in doubt is that in the investigation of natural objects no careful distinction is made between what is known to a certainty and what is known only with a certain amount of assurance. He discusses the question of deductive and inductive science, and considers that even those who depend on experience will not infrequently be found in error, because their conclusions are wider than their premises, and because it only too often happens that they admit principles as true for which they have no sure evidence. Stensen considered it important, therefore, not to hurry on in the explanation of things, but, so far as possible, to cling to old-time principles that had been universally accepted, since nearly always these would be found to contain fruitful germs of truth.
He was universally acknowledged as one of the greatest original thinkers of his time, and his conversion to the Church did much to dissipate religious prejudices among those of German nationality. His influence over distinguished visitors who came to Florence, and who were very glad to have the opportunity of making his acquaintance, was such that not a few Northern visitors became, like himself, converts to the Church.
It was in the midst of this that the request of the Duke of Hanover came that he should consent to become the bishop of his capital city. It was only after Stensen had been put under holy obedience that he would consent to accept the proffered dignity. His first thought was to distribute all his goods among the poor, and betake himself even without shoes on his feet, on a pedestrian journey to Rome. First, however, he made a pilgrimage to Loretto, where he arrived so overcome by the fatigue of the journey that the clergyman who took care of him while there, insisted on his accepting a pair of shoes from him, though he could not prevail upon him to travel in any other way than on foot.
His first action, after his consecration as bishop, was to write a letter, sending his episcopal benediction to Sister Maria Flavia, to whom he felt he owed the great privilege of his life. His lasting sense of satisfaction and consolation in his change of religion may be appreciated from what is, perhaps, the most interesting personal document that we have from Stensen's own hand, in which, on the eighteenth anniversary of his conversion, he writes to a friend to describe his feelings. "To-morrow," he says, "I shall finish, God willing, the eighteenth year of my happy life as a member of the Church. I wish to acknowledge once more my thankfulness for the part which you took under God in my conversion. As I hope to have the grace to be grateful to Him forever, so I sigh for the opportunity to express my thankfulnes to you and your family. I can feel that my own ingratitude toward God, my slowness in His service, make me unworthy of His graces; but I hope that you who have helped me to enter his service will not cease to pray, so that I may obtain pardon for the past and grace for the future, in order in some measure to repay all the favors that have been conferred on me."
The distinguishing characteristic of his life as a bishop was his insistence on poverty as the principal element of his existence. He refused to enter his diocese in state in the carriage which the Duke offered to provide for him, but proceeded there on foot. No question of supposed dignity could make him employ a number of servants, and his only retainers were converts made by himself, who helped in the household and whom he treated quite as equals. He became engaged in one controversy on religious matters, but said that he did not consider that converts had ever been made by controversies. He compared it, indeed, to the gladiatorial contests in which the contestants had their heads completely enveloped in armor, so as to prevent any possible penetration of the weapons of an opponent. He insisted especially that in religious controversies the contending parties do not realize the significance given to words by each other, and that therefore no good can result.
After a time, Stensen did not find his work in Hamburg very satisfactory, because it was typically a missionary country, and the Jesuit missionaries who had been introduced were accomplishing all that could be hoped for. Accordingly, when the Duke of Mecklenburg-Schwerin became a convert to the Catholic Church, and asked that Stensen should be sent as a bishop into his dukedom, the request was complied with. Here, in the hardest kind of labor as a missionary, and in the midst of poverty that was truly apostolic, Stensen worked out the remaining years of his life. At his death he was looked upon as almost a saint. Notwithstanding his close relationship with two reigning princes, he did not leave enough personal effects to defray the expenses of his funeral. Besides his bishop's ring, and the very simple episcopal cross he wore, he had nothing of any value except some relics of St. Francis Xavier, St. Ignatius Loyola, and St. Philip Neri, which he had prized above all other treasures.
His missionary labors had not been marked by any very striking success in the number of converts made. In this his life would seem to have been a bitter personal disappointment. He never looked upon it as such, however, but continued to be eminently cheerful and friendly until the end. As a matter of fact, the influence of his career was to be felt much more two centuries after his death than during his lifetime. At the present moment, his life is well known in northern Germany, thanks to the biographic sketch written by Father Plenkers for the Stimmen aus Maria Laach, which has been very widely circulated since its appearance in 1884. Something of the reaction among scientific minds in Germany toward a healthier orthodoxy of feeling, with regard to great religious questions, is undoubtedly due to the spread of the knowledge of the career of the great anatomist and geologist who gave up his scientific work for the sake of the spread of the higher truth.
After his death the Medici family asked for and obtained the privilege of having his body buried in San Lorenzo at Florence, with the members of the princely Medici house. More and more do visitors realize that the tablet over his remains chronicles the death of a man who was undoubtedly one of the world's great scientists, and one of the most original thinkers of his time, and that time a period greatly fertile in the history of science.
VII.
ABBÉ HAÜY, FATHER OF CRYSTALLOGRAPHY
They continue this day as they were created, perfect in number and measure and weight, and from the ineffaceable characters impressed on them we may learn that those aspirations after accuracy in measurement, truth in statement, and justice in action, which we reckon among our noblest attributes as men, are ours because they are essential constituents of the image of Him who in the beginning created not only heaven and earth, but the materials of which heaven and earth consist.–CLERK MAXWELL On the Molecule, "Nature," Vol. VIII. 1873.
VII.
ABBÉ HAÜY, FATHER OF CRYSTALLOGRAPHY
12Modern learning is gradually losing something of the self-complacency that characterized it in so constantly harboring the thought that the most important discoveries in physical science came in the nineteenth century. A more general attention to critical history has led to the realization that many of the primal discoveries whose importance made the development of modern science possible, came in earlier centuries, though their full significance was not then fully appreciated. The foundations of most of our modern sciences were, indeed, laid in the eighteenth century, but some of them came much earlier. It is genius alone that is able to break away from established traditions of knowledge, and, stepping across the boundary into the unknown, blaze a path along which it will be easy for subsequent workers to follow. Only in recent years has the due meed of appreciation for these great pioneers become part of the precious traditions of scientific knowledge.
We have seen that clergymen were great original investigators in science in the older times and we shall find, though it may be a source of astonishment to most people that even our modern science has had some supreme original workers, during the last two centuries, in the ranks of the Catholic clergy.
The eighteenth century was not behind the seventeenth in original contributions made to science by clergymen. About the middle of the century, a Premonstratensian monk, Procopius Dirwisch by name, of the little town of Prenditz in Bohemia, demonstrated the identity of electrical phenomena with lightning, thus anticipating the work of our own Franklin. Dirwisch dared to set up a lightning-conductor, by which during thunderstorms he obtained sparks from clouds, and also learned to appreciate the danger involved in this experiment. When, in 1751, he printed his article on this subject, he pointed out this danger. His warning, however, was not always heeded, and at least one subsequent experimenter was struck dead by a charge of electricity.
Just at the junction of the last two centuries, Father Piazzi enriched the realm of science by one of the most important of modern discoveries in astronomy. On the night of 31 December, 1800–1 January, 1801, he discovered the little planet Ceres. This was the first of the asteroids, so many more of which were to be revealed to astronomical study during the next half-century. Father Piazzi's discovery was made, not by accident, but as the result of detailed astronomical work of the most painstaking character. He had set out to make a map of the heavens, and to determine and locate the absolute position of all the visible stars. He had succeeded in cataloguing over 7,000 stars when his attention was called to one, hitherto supposed to be fixed, which he found had moved, during the interval between two observations, from its original position. He made still other observations, and thus determined the fact that it was a planetoid and not a fixed star with which he had to deal. Needless to say, his discovery proved a strong incentive to patient astronomical study of the same kind; and it is to these, rather than to great single discoveries, that we owe whatever progress in astronomy was made during the nineteenth century.
Contemporary with both of these last-mentioned men, and worthy to share in the scientific honors that were theirs, was the Abbé Haüy, who toward the end of the second half of the eighteenth century founded the science of crystallography; made a series of observations the value of which can never be disputed, originated theories some of which have served down to our own time as the basis of crystal knowledge, and attracted the attention of many students to the new science because of his charming personal character and his winning teaching methods. His life is a typical example of the value of work done in patient obscurity, founded on observation, and not on brilliant theories; and what he accomplished stamps him as one of the great scientific geniuses of all time–one of the men who widened the bounds of knowledge in directions hitherto considered inaccessible to the ordinary methods of human investigation.
It is a commonplace of the lecturer on popular science at the present day, that the impulse to the development of our modern scientific discoveries which became so marked toward the end of the eighteenth century, was due in a noteworthy degree to the work of the French Encyclopedists. Their bringing together of all the details of knowledge in a form in which it could be readily consulted, and in which previous progress and the special lines of advance could be realized, might be expected to prove a fruitful source of suggestive investigation. As a matter of fact, however, a detailed knowledge of the past in science often seems to be rather a hindrance than a help to original genius, always prone to take its own way if not too much disturbed by the conventional knowledge already gained. Most of the great discoverers in science were comparatively young men when they began their careers as original investigators; and it was apparently their freedom from the incubus of too copious information that left their minds untrammelled to follow their own bent in seeking for causes where others had failed to find any hints of possible developments.
This was certainly the case with regard to many of those distinguished founders who lived in centuries prior to the nineteenth. Most of them were men under thirty years of age, and not one of them had been noted, before he began his own researches, for the extent of his knowledge in the particular department of science in which his work was to prove so fruitful. Their lives illustrate the essential difference there is between theory and observation in science. The theorizer reaches conclusions that are popular as a rule in his own generation, and receives the honor due to a progressive scientist; the observer usually has his announcements of what he has actually seen scouted by those who are engaged in the same studies, and it is only succeeding generations who appreciate how much he really accomplished.
This was especially exemplified in the case of the Abbé Haüy, whose work in crystallography was to mean so much. What he learned was not from books, but from contact with the actual objects of his department of science; and it is because the example of a life like this can scarcely fail to serve a good purpose for the twentieth-century student, in impressing the lesson of the value of observation as opposed to theory, that its details are retold.
Réné Just Haüy was born 28 February, 1743, in the little village of Saint-Just, in the Department of Oise, somewhat north of the center of France. Like many another great genius, he was the son of very poor parents. His father was a struggling linen-weaver, who was able to support himself only with difficulty. At first there seemed to be no other prospect for his eldest son than to succeed to his father's business. Certainly there seemed to be no possibility that he should be able to gain his livelihood by any other means than by the work of his hands.
Fortunately, however, there was in Haüy's native town a Premonstratensian monastery, and it was not long before some of the monks began to notice that the son of the weaver was of an especially pious disposition and attended church ceremonies very faithfully. The chance was given to him to attend the monastery school, and he succeeded admirably in his studies. As a consequence, the prior had his attention directed to the boy, and found in him the signs of a superior intelligence. He summoned the lad's parents and discussed with them the possibility of obtaining for their son an education. There were many difficulties in the way, but the principal one was their absolute financial inability to help him. If the son was to obtain an education, it must be somehow through his own efforts, and without any expense to his parents.
The prior thereupon obtained for young Haüy a position as a member of a church choir in Paris; and, later, some of those to whom he had recommended the boy secured for him a place in the college of Navarre. Here, during the course of a few years, he made such an impression upon the members of the faculty that they asked him to become one of the teaching corps of the institution. It was a very modest position that he held, and his salary scarcely more than paid for his board and clothes and a few books. Haüy was well satisfied, however, because his position provided him with opportunities for pursuing the studies for which he cared most. At this time he was interested mainly in literature, and succeeded in learning several languages, which were to be of considerable use to him later on in his scientific career.
After some years spent in the college of Navarre he was ordained priest, and not long afterward became a member of the faculty of the college of Cardinal Lemoine. Here his position was somewhat better, and he was brought in contact with many of the prominent scholars of Paris. He seems, however, to have been quite contented in his rather narrow circle of interests, and was not specially anxious to advance himself. It is rather curious to realize that a man who was later to spend all his time in the pursuit of the physical sciences, knew practically nothing at all about them, and certainly had no special interest in any particular branch of science, until he reached the age of almost thirty years.
Even then his first introduction to serious science did not come because of any special interest that had been aroused in his own mind, but entirely because of his friendship for a distinguished old fellow-professor, whose walks he used to share, and who was deeply interested in botany. This was the Abbé Lhomond, a very well-known scholar, to whom we owe a number of classic text-books arranged especially for young folk.
The Abbé's recreation consisted in botanizing expeditions; and Haüy, who had chosen the kindly old priest as his spiritual director, was his most frequent companion. Occasionally, when M. Lhomond was ailing, and unable to take his usual walks, Haüy spent the time with him. He rather regretted the fact that he did not know enough about botany to be able to make collections of certain plants to bring to the professor at such times, in order that the latter might not entirely miss his favorite recreation. Accordingly, one summer when he was on his vacation at his country home, he asked one of the Premonstratensian monks, who was very much interested in botany, to teach him the principles of the science, so as to enable him to recognize various plants. Of course his request was granted. He expected to have a pleasant surprise for Abbé Lhomond on his return, and to draw even closer in his friendly relations with him, because of their mutual interest in what the old Abbé called his scientia amabilis (lovely science). His little plan worked to perfection, and there was won for the study of physical science a new recruit, who was to do as much as probably any one of his generation to extend scientific knowledge in one department, though that department was rather distant from botany.