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 [{183}] 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 [{184}] 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 [{185}] 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 [{186}] 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.