Haüy's interest in botany, however, was to prove only temporary. It brought him in contact with other departments of natural history, and it was not long before he found that his favorite study was that of minerals, and especially of the various forms of crystals. So absorbed did he become in this subject that nothing pleased him better than the opportunity to spend long days in the investigation of the comparative size and shape of the crystals in the museum at Paris. A friend has said of him that, whether they were the most precious stones and gems or the most worthless specimens of ordinary minerals, it was always only their crystalline shape that interested Haüy. Diamonds he studied, but only in order to determine their angles; and apparently they had no more attraction for him than any other well-defined crystal–much less, indeed, than some of the more complex crystalline varieties, which attracted his interest because of the difficulty of the problems they presented.
Like many another advance in science, Haüy's first great original step in crystallography was the result of what would be called a lucky accident. These accidents, however, be it noted, happen only to geniuses who are capable of taking advantage of them. How many a man had seen an apple fall from a tree before this little circumstance gave Newton the hint from which grew, eventually, the laws of gravity! Many a man, doubtless, had seen little boys tapping on logs of wood, to hear how well sound was carried through a solid body, without getting from this any hint, such as Laennec derived from it, for the invention of the stethoscope. So, too, many a person before Haüy's time had seen a crystal fall and break, leaving a smooth surface, without deriving any hint for the explanation of the origin of crystals.
According to the familiar story, Haüy was one day looking over a collection of very fine crystals in the house of Citizen Du Croisset, Treasurer of France. He was examining an especially fine specimen of calcspar, when it fell from his hands and was broken. Of course the visitor was much disturbed by this accident. His friend, however, in order to show him that he was not at all put out at the breaking of the crystal, insisted on Haüy's taking it with him for purposes of study, as they had both been very much interested in the perfectly smooth plane of the fracture. As Haüy himself says, this broken portion had a peculiarly brilliant lustre, "polished, as it were by nature," as beautifully as the outer portions of the crystal; thus demonstrating that in building up of so large a crystal there must have been certain steps of progress, at any of which, were the formation arrested, smooth surfaces would be found.
On taking the crystal home, Haüy proceeded further to break up the smaller fragment; and he soon found that he could remove slice after slice of it, until there was no trace of the original prism, but in place of it a rhomboid, perfectly similar to Iceland spar, and lying in the middle of what was the original prism. This fact seemed to him very important. From it he began the development of a theory of crystallization, using this observation as the key. Before this time it had been hard for students of mineralogy to understand how it was that substances of the same composition might yet have what seemed to be different crystalline forms. Calcspar, for instance, might be found crystallized in forms, apparently, quite at variance with one another.
By his studies, however, Haüy was able to determine that whenever substances of the same composition crystallized, even though the external form of the crystals seemed to be different, all of them were found to have the same internal nucleus. Whenever the mineral under observation was chemically different from another, then the nucleus also had a distinctive character; and so there came the law that all substances of the same kind crystallized in the same way, notwithstanding apparent differences. Indeed, one of the first results of this law was the recognition of the fact that when the crystalline forms of two minerals were essentially different, then, no matter how similar they might be, there was sure to be some chemical difference. This enabled Haüy to make certain prophecies with regard to the composition of minerals.
A number of different kinds of crystals had been classed together under the name of heavyspar. Some of these could not, by the splitting process, be made to produce nuclei of similar forms, and the angles of the crystals were quite different. Haüy insisted that, in spite of close resemblances, there was an essential distinction in the chemical composition of these two different crystalline formations; and before long careful investigation showed that, while many of the specimens called heavyspar contain barium, some of them contain a new substance–strontium–which had been very little studied heretofore. This principle did not prove to be absolute in its application; but the amount of truth in it attracted attention to the subject of crystallography because of the help which that science would afford in the easy recognition of the general chemical composition of mineral substances. The most important part of Haüy's work was the annunciation of the law of symmetry. He emphasized the fact that the forms of crystals are not irregular or capricious, but are very constant and definite, and founded on absolutely fixed and ascertainable laws. He even showed that, while from certain crystalline nuclei sundry secondary forms may be derived, there are other forms that cannot by any possibility occur. Any change of crystalline form noticed in his experiments led to a corresponding change along all similar parts of the crystal. The angles, the edges, the faces, were modified in the same way, at the same time. All these elements of mensuration within the crystal Haüy thought could be indicated by rational coefficients.
Crystallography, however, did not absorb all Haüy's attention. He further demonstrated his intellectual power by following out other important lines of investigation that had been suggested by his study of crystals. It is to him more than to any other, for instance, that is due the first steps in our knowledge of pyro-(or thermo-) electricity. Mr. George Chrystal, professor of mathematics at the University of St. Andrews, in the article on electricity written for the ninth edition of the Encyclopedia, says it was reserved for the Abbé Haüy in his Treatise on Mineralogy to throw a clear light on this curious branch of the science of electricity.
To those who are familiar with the history of the development of this science it will be no surprise to find a clergyman playing a prominent role in its development. During the days of the beginning of electricity many ecclesiastics seem to have been particularly interested in the curious ways of electrical phenomena, and as a consequence they are the original discoverers of some of the most important early advances. Not long before this, Professor Gordon, a Scotch Benedictine monk who was teaching at the University of Erfurt, constructed the first practical electrical machine. Kleist, who is one of the three men to whom is attributed the discovery of the principle of storing and concentrating electricity, and who invented the Leyden Jar, which was named after the town where it was first manufactured, was also a member of a Religious Order. As we have already stated, Dirwisch, the Premonstratensian monk, set up a lightning-conductor by which he obtained sparks from the clouds even before our own Franklin.
Abbé Haüy was only following a very common precedent, then, when he succeeded by his original research in setting the science of pyro-electricity firmly on its feet. It is true, others before him had noted that substances like tourmaline possessed electrical properties. There is even some good reason for thinking that the lyncurium of the ancients which, according to certain of the Greek philosophers, especially Theophrastus, who seems to have made a close study of the subject, attracted light bodies, was really our modern tourmaline. In modern times the Dutch found this mineral in Ceylon and, because it attracted ashes and other light substances to itself, called it aschentriker--that is, attractor of ashes. Others had still further experimented with this curious substance and its interesting electrical phenomena. It remained for Abbé Haüy, however, to demonstrate the scientific properties of tourmaline and the relations which its electrical phenomena bore toward the crystalline structure of the mineral. He showed that the electricity of tourmaline decreases rapidly from the summits or poles toward the middle of the crystal. As a matter of fact, at the middle of the crystal its electrical power becomes imperceptible.
He showed also that each particle of a crystal that exhibits pyro-electricity is itself a source of the same sort of electricity and exhibits polarity. His experimental observations served to prove also that the pyro-electric state has an important connexion with the want of symmetry in the crystals of the substances that exhibit this curious property. In tourmaline, for instance, he found the vitreous charge always at the summit of the crystal which had six faces, and the resinous electricity at the summit of the crystal with three faces.
His experiments soon showed him, too, that there were a number of other substances, besides tourmaline, which possessed this same electrical property when subjected to heat in the crystalline stage. Among these were the Siberian and Brazilian topaz, borate of magnesia, mesotype, sphene, and calamine. In all of these other pyro-electrical crystals, Haüy detected a corresponding deviation from the rules of symmetry in their secondary crystals to that which occurs in tourmaline. In a word, after he had concluded his experiments and observations there was very little left for others to add to this branch of science, although such distinguished men as Sir David Brewster in England were among his successors in the study of the peculiar phenomena of pyro-electricity.
It may naturally enough be thought that, born in the country, of poor parents, and compelled to work for his living, Haüy would at least have the advantage of rugged health to help him in his career. He had been a delicate child, however; and his physical condition never improved to such an extent as to inure him to hardships of any kind. One of his biographers has gone so far as to say that his life was one long malady. The only distraction from his almost constant suffering was his studies. Yet this man lived to be nearly eighty years of age, and accomplished an amount of work that might well be envied even by the hardiest.
In the midst of his magnificent success as a scientist, Haüy was faithful to all his obligations as a priest. His name was known throughout Europe, and many of the scientific societies had considered that they were honoring themselves by conferring titles, or degrees, upon him; but he continued to be the humble, simple student that he had always been.
At the beginning of the Revolution, Abbé Haüy was among the priests who refused the oath which the Republican government insisted on their taking, and which so many of them considered derogatory to their duty as churchmen. Those who refused were thrown into prison, Haüy among them. He did not seem to mind his incarceration much, but he was not a little perturbed by the fact that the officers who made the arrest insisted on taking his precious papers, and that his crystals were all tossed aside and many of them broken. For some time he was kept in confinement with a number of other members of the faculty of the University, mainly clergymen, in the Seminary of St. Firmin, which had been turned into a temporary jail.
Haüy did not allow his studies to be entirely interrupted by his imprisonment. He succeeded in obtaining permission to have his cabinets of crystals brought to his cell, and he continued his investigation of them. It was not long before powerful friends, and especially his scientific colleague, Gregory St. Hilaire, interested themselves in his case, and succeeded in obtaining his liberation. When the order for his release came, however, Haüy was engaged on a very interesting problem in crystallography, and he refused to interrupt his work and leave the prison. It was only after considerable persuasion that he consented to go the next morning. It may be added that only two weeks later many from this same prison were sent to the guillotine.
It is rather remarkable that the Revolutionary government, after his release, did not disturb him in any way. He was so much occupied with his scientific pursuits that he seems to have been considered absolutely incapable of antagonizing the government; and, as he had no enemies, he was not denounced to the Convention. This was fortunate, because it enabled him to pursue his studies in peace. There was many another member of the faculty of the University who had not the same good fortune. Lavoisier was thrown into prison, and, in spite of all the influence that could be brought to bear, the great discoverer of oxygen met his death by the guillotine. At least two others of the professors in the physical department, Borda and De Lambre, were dismissed from their posts. Haüy, though himself a priest who had refused to take the oath, and though he continued to exercise his religious functions, did not hesitate to formulate petitions for his imprisoned scientific friends; yet, because of his well-known gentleness of character, this did not result in arousing the enmity of any members of the government, or attracting such odious attention as might have made his religious and scientific work extremely difficult or even prevented it entirely.
Notwithstanding the stormy times of the French Revolution and the stirring events going on all round him in Paris, Haüy continued to study his crystals in order to complete his observations; and then he embodied his investigations and his theories in his famous "Treatise on Crystallography." This attracted attention not only on account of the evident novelty of the subject, but more especially because of the very thorough method with which Haüy had accomplished his work. His style, says the historian of crystallography, was "perspicuous and elegant. The volume itself was noteworthy for its clear arrangement and full illustration by figures." In spite of its deficiencies, then deficiencies which must exist in any ground-breaking work–this monograph has had an enduring influence. Some of the most serious flaws in his theory were soon brought to light because of the very stimulus afforded by his investigations.
As to the real value of his treatise, perhaps no better estimate can be formed than that given by Cuvier in his collection of historical eulogies (Vol. III, p. 155): "In possession of a large collection, to which there flowed from all sides the most varied minerals, arranged with the assistance of young, enthusiastic, and progressive students, it was not long before there was given back to Haüy the time which he had apparently wasted over other things. In a few years he raised up a wondrous monument, which brought as much glory to France as it did somewhat later to himself. After centuries of neglect, his country at one bound found itself in the first rank in this department of natural science. In Haüy's book are united in the highest degree two qualities which are seldom associated. One of these is that it was founded on an original discovery which had sprung entirely from the genius of its author; and the other is that this discovery is pursued and developed with almost unheard-of persistence down even to the least important mineral variety. Everything in the work is great, both as regards conception and detail. It is as complete as the theory it announces."
It was not surprising, then, that, after the death of Professor Dolomieu, Haüy should be raised to the chair of mineralogy and made director of that department in the Paris Museum of Natural History. Here he was to have new triumphs. We have already said that his book was noted for the elegance of its style and its perspicuity. As the result of this absolute clearness of ideas, and completeness and simplicity of expression, Haüy attracted to him a large number of pupils. Moreover, all those interested in the science, when they came in contact with him, were so charmed by his grace and simplicity of manner that they were very glad to attend his lectures and to be considered as his personal friends. Among his listeners were often such men as La Place, Berthollet, Fourcroy, Lagrange and Lavoisier.
It was not long before honors of all kinds, degrees from universities and memberships in scientific societies all over Europe, began to be heaped upon Haüy. They did not, however, cause any change in the manners or mode of life of the simple professor of old times. Every day he continued to take his little walks through the city, and was very glad to have opportunity to be of assistance to others. He showed strangers the way to points of interest for which they inquired, whenever it was necessary, obtained entrance cards for them to the collection; and not a few of those who were thus enabled to take advantage of his kindness failed to realize who the distinguished man was to whom they owed their opportunities. His old-fashioned clothing still continued to be quite good enough for him, and his modest demeanor and simple speech did not betray in any way the distinguished scientist he had become.
Some idea of the consideration in which the Abbé Haüy was held by his contemporaries may be gathered from the fact that several of the reigning monarchs of Europe, as well as the heirs apparent to many thrones, came at some time or other to visit him, to see his collection, and to hear the kindly old man talk on his hobby. There was only one other scientist in the nineteenth century–and that was Pasteur, toward the end of it–who attracted as much attention from royalty. Among Haüy's visitors were the King of Prussia, the Emperor of Austria, the Archduke John, as well as the Emperor of Russia and his two brothers, Nicholas and Michael, the first of whom succeeded his elder brother, Alexander, to the throne, and half a century later was ruling Russia during the Crimean War. The Prince Royal of Denmark spent a portion of each year for several years with Haüy, being one of his intimates, who was admitted to his room while he was confined to his bed, and who was permitted to share his personal investigations and scientific studies.
His most striking characteristic was his suavity toward all. The humblest of his students was as sure to receive a kindly reception from him, and to have his difficulties solved with as much patience as the most distinguished professor in this department. It was said that he had students of all classes. The attendants at the normal school were invited to visit him at his house, and he permitted them to learn all his secrets. When they came to him for a whole day, he insisted on taking part in their games, and allowed them to go home only after they had taken supper with him. All of them looked upon him as a personal friend, and some of them were more confidential with him than with their nearest relatives. Many a young man in Paris during the troublous times of the Revolutionary period found in the good Abbé Haüy not only a kind friend, but a wise director and another father.
It is said that one day, when taking his usual walk, he came upon two former soldiers who were just preparing to fight a duel and were on their way to the dueling ground. He succeeded in getting them to tell him the cause of their quarrel, and after a time tempted them to come with him into what I fear we should call at the present day a saloon. Here, over a glass of wine, he finally persuaded them to make peace and seal it effectually. It is hard to reconcile this absolute simplicity of character and kindness of heart with what is sometimes assumed to be the typical, distant, abstracted, self-centered ways of the great scientist.
Few men have had so many proofs of the lofty appreciation of great contemporaries. Many incidents serve to show how much Napoleon thought of the distinguished scholar who had created a new department of science and attracted the attention of the world to his splendid work at Paris. Not long after he became emperor, Napoleon named him Honorary Canon of the Cathedral of Notre Dame; and when he founded the Legion of Honor, he made the Abbé one of the original members. Shortly after these dignities had been conferred upon him, it happened that the Abbé fell ill; and Napoleon, having sent his own physician to him, went personally to call on him in his humble quarters, saying to the physician: "Remember that you must cure Abbé Haüy, and restore him to us as one of the glories of our reign." After Napoleon's return from Elba, he told the Abbé that the latter's "Treatise on Crystallography" was one of the books that he had specially selected to take with him to Elba, to while away the leisure that he thought he would have for many years. Abbé Haüy's independence of spirit, and his unselfish devotion to his native country, may be best appreciated from the tradition that after the return from Elba, when there was a popular vote for the confirmation of Napoleon's second usurpation, the old scientist voted, No.
In spite of his constant labor at his investigations, his uniformly regular life enabled him to maintain his health, and he lived to the ripe age of over seventy-nine. Toward the end of his career, he did not obtain the recognition that his labors deserved. After the Restoration, he was not in favor with the new authorities in France, and he accordingly lost his position as professor at the University. The absolute simplicity of life that he had always maintained now stood him in good stead; and, notwithstanding the smallness of his income, he did not have to make any change in his ordinary routine. Unfortunately, an accidental fall in his room at the beginning of his eightieth year confined him to his bed; and then his health began to fail very seriously. He died on the 3 June, 1822.
He had shown during his illness the same gentleness and humility, and even enthusiasm for study whenever it was possible, that had always characterized him. While he was confined to his bed he divided his time between prayer, attention to the new edition of his works which was about to appear, and his interest for the future of those students who had helped him in his investigations. Cuvier says of him that "he was as faithful to his religious duties as he was in the pursuit of his studies. The profoundest speculations with regard to weighty matters of science had not kept him from the least important duty which ecclesiastical regulations might require of him." There is, perhaps, no life in all the history of science which shows so clearly how absolutely untrue is the declaration so often made, that there is essential opposition between the intellectual disposition of the inquiring scientist and those other mental qualities which are necessary to enable the Christian to bow humbly before the mysteries of religion, acknowledge all that is beyond understanding in what has been revealed, and observe faithfully all the duties that flow from such belief.