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 {182} 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.