A History of Inventions, Discoveries, and Origins, Volume I (of 2). Johann Beckmann

Чтение книги онлайн.

СКАЧАТЬ when rubbed, is, like the magnet, endued with an attractive power is to be found in a passage of John Serapion, the Arabian, pointed out to me by Professor Bütner218. This stone indeed cannot with much probability be taken for the tourmaline, as all precious stones, when heated, have the same property; but it is worthy of remark, that, like the lyncurium of the ancients, it belongs to the hyacinths, the colour of which many of the real tourmalines have; and among those of the island of Ceylon there are, perhaps, some which ought to be classed among the hyacinths, rather than among the schorls.

      The real tourmaline was first brought from Ceylon, and made known by the Dutch, about the end of the seventeenth or beginning of the eighteenth century. It is commonly believed that the first account of it ever published is that to be found in the Memoirs of the Academy of Sciences at Paris for the year 1717; but it appears that fuller and more accurate descriptions of the properties of that stone were given in German works ten years before. The earliest information that I know respecting it is in a book now almost and justly forgotten, entitled Curious Speculations during Sleepless Nights219. In a passage, where the author, speaking of hard and glassy bodies which attract light substances, affirms that this property is not magnetic, he says, “The ingenious Dr. Daumius, chief physician to the Polish and Saxon troops on the Rhine, told me, that in the year 1703 the Dutch first brought from Ceylon in the East Indies a precious stone called tourmaline, or turmale, and named also trip, which had the property, that it not only attracted the ashes from the warm or burning coals, as the magnet does iron, but also repelled them again, which was very amusing; for as soon as a small quantity of ashes leaped upon it, and appeared as if endeavouring to writhe themselves by force into the stone, they in a little sprang from it again, as if about to make a new effort; and on this account it was by the Dutch called the ashes-drawer. The colour of it was an orange-red heightened by a fire colour. When the turf coals were cold, it did not produce these effects, and it required no care like the magnet. I have considered whether it would not attract and repel the ashes of other burning coals as well as those of turf; and I have no doubt, that, if heated, it would attract other things besides ashes.”

      This whole passage has been inserted word for word, without variation or addition, and without telling the source from which taken, in a book perhaps equally forgotten, called Observationes curioso-physicæ, or Remarks and Observations on the great Wonders of the World, by Felix Maurer, physician220. This thick volume is entirely compiled from a number of works, the names of which are not mentioned.

      In the Catalogue of the collection of natural curiosities belonging to Paul Hermann, which were sold at Leyden in June 1711, I find, among the precious stones, Chrysolithus Turmale Zeylon. Though no description is added, it cannot be doubted that our tourmaline is meant. From this however we learn that the name together with the stone came to us from Ceylon, as Watson has remarked. We learn further, that the stone was at first considered as a chrysolite, and perhaps it may be mentioned under this name in the old accounts of Ceylon. Hermann, whose service to botany is well known, was in that island from 1670 to 1677; and it might be presumed, from his spirit of inquiry, that, had he known this stone, he would somewhere or other in his works have taken notice of its properties: but I find no mention of it either in his Cynosura Materiæ Medicæ, or in Musæum Zeylonicum.

      In the year 1719 the Academy of Sciences at Paris announced in their memoirs for 1717, that in the latter year M. Lemery had laid before them a stone found in a river in the island of Ceylon, which attracted and repelled light bodies221. It is there called a small magnet, though some difference between the two stones was admitted; but the German naturalist before-mentioned, denies that the tourmaline is endowed with magnetic virtue. It is however very remarkable, that though it is said, in the Memoirs of the Academy, that it has the power of attracting and repelling, no mention is made that it acquires that property, only after it has been heated, which is expressly remarked by the German. Those therefore who wish to ascribe to the ancients a knowledge of the tourmaline may say, If the editor of the Memoirs of the French Academy could forget this circumstance, is it not highly probable that Theophrastus might have forgot it in describing the lyncurium; Pliny, in describing the carbuncle; and Serapion, in describing his hyacinth?

      After this period the tourmaline must have been very scarce in Europe; for when Muschenbroek made his well-known experiments with the loadstone, and spared no labour to carry them to the utmost extent, he was not acquainted with the nature of the tourmaline, which, according to the account given of it by the Academy at Paris, he considered as a magnet, as he himself says in the preface to his first dissertation, published in 1724.

      About the year 1740 however some German naturalists made experiments with this stone, in order to discover the real cause of its attractive property. These may be seen, under the article Trip, in the well-known Dictionary of Natural History which is often printed with Hübner’s preface; but I do not know to whom the honour belongs of having first investigated the properties of this stone. As the above dictionary is common, I shall give here only a very short extract from it: – “This stone was brought to Holland by some persons who had travelled in India, from the island of Ceylon, where it is found pretty frequently among the fine sand near Columbo, and sold to the German Jews. These caused it to be cut thinner, and the price of it soon rose to eight and ten Dutch florins. It has been since much dearer; but at present it is cheaper. It attracts not only ashes, but also metallic calces: it however attracts more easily and with greater force those which have been formed by means of sal-ammoniac, or the spirit of that salt. It acquires its attractive power only after it has been moderately heated; for when cold or heated to a greater degree it produces no effect, which the author ascribes to its being united with martial sulphur. The chrysolites and other precious stones of the island do not possess the same property.” As the author quotes the Laboratorium Zeylonicum, I consulted it, but found no information in it respecting the tourmaline. The first person who thought of explaining the property of the tourmaline by electricity was the great Linnæus, who in the preface to his Flora Zeylanica222, where he enumerates the productions of the island, calls it the electrical stone; but at that time, as he himself afterwards told me, he had not seen it.

      What Linnæus only conjectured, Æpinus proved at Berlin in 1757 by accurate observation and experiments, when endeavouring with Wilke to investigate the secret of negative and positive electricity. The history of their discoveries I shall here omit, as a better account of them than I could give has been published in the Transactions of the Swedish Academy by Wilke.

      [The discovery by Huygens, in 1678, of the polarization of light by double refraction, laid the foundation of a much more important application of the tourmaline; for MM. Biot and Seebeck, in their subsequent experiments, discovered that certain yellowish tourmalines, that is, those which are yellowish by refracted light, possessed the remarkable property of absorbing or checking one of the rays of a beam of polarized light, and transmitting the others. This discovery led to the use of tourmalines in most experiments which were subsequently made with polarized light. For this purpose, the tourmaline, which generally crystallizes in the form of a long prism, is cut lengthwise, that is, parallel to the axis of the prism, into plates about the 30th of an inch thick.

      The invention of Mr. Nichol of a method of destroying one of the rays of a polarized beam in a crystal of calcareous spar, has however in later times entirely replaced the use of the tourmaline in optical science, the colour of the tourmaline being a disadvantage which is entirely removed in the use of Nichol’s prism223.]

      SPEAKING-TRUMPET

      Instruments by which the voice could be so strengthened as to be heard at a much greater distance than would otherwise have been possible, were known in the earliest ages; for of all musical instruments, wind instruments were first invented, and their use in war to give the signal of battle, we find mentioned in JobСКАЧАТЬ