There seems some little likelihood that certain examples of the gem called lychnis and noted by Pliny may have been varieties of the tourmaline. As the first tourmalines brought to modern Europe came to Holland from Ceylon, we might conjecture that those kinds of lychnis said by Pliny to have been brought from India had a like origin. Of these Indian specimens, the finest examples of this gem, one kind resembled the carbuncle or ruby, while another bore the designation Ionia because its color was like that of the violet (in Greek ion). The most striking peculiarity of the lychnis was its power to attract straws or bits of paper, when it had been heated by the sun’s rays or by hand-friction.[[91]]
Such is the confusion in the statements made by the early Greek and Latin writers as to the emerald, under which generic name they seem to have included almost all green stones of any ornamental or other value, that we cannot absolutely reject the conjecture[[92]] that Theophrastus (third century B.C.), the earliest of these writers on precious stones, might have referred to specimens of green tourmaline, when he states that the true emerald appeared to have been produced from jasper, as one of the Cyprian specimens was said to have consisted of one-half jasper and the other half emerald, the metamorphosis as yet being incomplete.[[93]] We admit that if Theophrastus uses the word jasper here to signify the reddish variety, we would have the combination of green and red zones in a single crystal sometimes observable in tourmaline. How this can be reconciled with the previous statement of the same author that the Cyprian “emeralds” which came from the copper mines of that island were chiefly used for soldering gold, and hence seem to have been of the class of mineral called chrysocolla by ancient writers, is, however, not easy to suggest.[[94]]
The so-called Brazilian emeralds mentioned by the Dutch mineralogist, Johann de Laet, as having been found shortly before 1647 in mines near Spiritus Sanctus, may perhaps have been green tourmalines. These crystals were described by Gesner as of cylindrical form, striated, and of a vitreous lustre; their color was like that of the prase and they were transparent. Although De Laet adds the assertion that the Oriental emerald (green corundum) was as hard as the sapphire, the Brazilian emeralds approached more closely to the Oriental in point of hardness than did emeralds from any other source of supply;[[95]] and green sapphires have never been found in Brazil, while green tourmalines have been.
The earliest published work in which the electric properties of tourmaline are noted appears to be an anonymous or quasi anonymous treatise published in 1707, certain initial letters of the quaint title being italicized to indicate the initials of the author’s name.[[96]] The first scientist to derive the action of the so-called Aschentrekker or “Ash-Attractor” from electric energy is said to have been the great Linnæus, who bestowed upon the tourmaline the name of the “Electrical Stone.”[[97]]
The attractive properties of the tourmaline are said to have been first brought to scientific notice by M. Louis Lémery, in a report made during 1717 to the French Academy of Sciences; however, Lémery was inclined to attribute them to magnetic influence. That these phenomena of attraction and repulsion were really due to the electric properties of the stone was first clearly brought out by the German physicist, Franz Ulrich Theodor Aepinus, and his conclusions were communicated to the Berlin Academy of Sciences in 1756.[[98]] Aepinus made his experiments upon two specimens of tourmaline from Ceylon, which had been furnished him by Lehmann, a fellow-member of the Berlin Academy, who, as Aepinus frankly admits, first drew his attention to the electric action of the stone. That not only friction but heat also should develop the electric energy, both positive and negative, of the tourmaline, serves to differentiate it from many other potentially electric substances, in the case of which friction alone is effective.
A SIMPLE APPARATUS FOR ILLUSTRATING THE ELECTRIC PROPERTIES OF THE TOURMALINE
The stone is suspended from a hollow rod and will be attracted by the finger, if the latter be brought within a short distance of the tourmaline. When the stone has been slightly heated, its positive electricity will draw toward it the heart-shaped piece of paper, just as amber attracts paper, or magnetic iron does iron filings.
The specimen shown by M. Lémery to the French Academy of Sciences in 1717 is stated to have come from “a river in the Island of Ceylon,” and is described as being of small size, flat, orbicular, quite thin, of a brown color, and smooth brilliant surface.[[99]] Its peculiar property of attracting and then repelling ashes or iron filings as well as bits of paper, was duly noted. This specimen had cost M. Lémery 15 livres. After reciting the constant repulsion and attraction exercised by a magnet upon the needle, the attraction by the opposite pole, and repulsion by the same pole, he proceeds to remark that this Cinghalese stone acted quite differently, since it first attracted and then repulsed the same object presented in the same way. This intermittent or irregular action was in his opinion to be explained by the theory that a vortex was intermittently developed in the substance. As it begins the small bodies are attracted, when it ceases they remain stationary, but when it is renewed “and there emanates from the stone a material analogous to the magnetic emanation” then the bodies are repulsed. Another peculiarity was that the body which had been repulsed could not again be attracted, whence the conclusion was arrived at that the stone’s repellent force was superior to its attractive power. These necessarily somewhat inexact observations are interesting as marking one of the earliest attempts to explain these phenomena, even although the explanation is faulty.
The great French crystallographer, Abbé Haüy, relates his experiments on a tourmaline crystal.[[100]] He set this crystal in steel clamps, with a long stem which was inserted in a wooden handle, and then subjected the tourmaline to the heat of a brasier. As the heat augmented and penetrated the stone, its natural electric force became decomposed, the two component fluids being forced to separate from each other. It was now necessary to cool the tourmaline off a little; when too much heated the electrical phenomena were interrupted; they were also diminished in intensity when the stone became cool again. The perfect crystal chosen for experiment clearly showed the negative and positive electrical poles; even the smallest pieces showed this, and, indeed, if a very small piece were broken off the positively electric side of a crystal, it would preserve this positive electricity and soon develop a negative electricity also.
We may be somewhat loath to doubt the tale that little Dutch children were the first to note what to them was the queer action of some bits of tourmaline, but preference should probably be given to the statement that the discovery of the electric phenomena induced by heating in these stones was due to the fact that some Dutch jewellers put specimens of tourmaline in the fire to test their hardness, and then found that the stones attracted or repelled the ashes of the fire.[[101]]