WINCKLER (Prof. J. H.) Gedanken von den Eigenschaften, Wirkungen und Ursachen der Elektricität. 8vo. Leipzig, 1744.
YELIN (J. C. von). Ueber die Blitzableiter aus Messingdrahtstricken. 8vo. München, 1824.
HISTORY, NATURE, AND MODE OF APPLICATION.
‘First let me talk with this philosopher: What is the cause of thunder?’ asks Shakspeare in ‘King Lear’ but without giving a reply. The ‘philosopher’ of Shakspeare’s days had no answer to make; nor had any others long after. From the dawn of history till within comparatively modern times, thunder and lightning were mysteries to the human mind; nor did there exist so much as a surmise that there might be any connection between them and the equally mysterious agent called electricity. The latter force indeed revealed itself early to attentive observers, though in forms very different from those known at the present time. The Greeks found out that amber, or ‘electron,’ attracted certain other bodies under friction, and named the force after it; and the Romans were aware that the shocks discharged by the torpedo fish were of electrical nature, and they used them for the cure of rheumatic complaints in the reign of the Emperor Tiberius. Both Greeks and Romans also observed the sparks emitted, under certain circumstances, from clothing and from the fur of animals. But this represented the total sum of knowledge about electricity for ages and ages.
It was not until the year 1600 that Dr. William Gilbert, physician to Queen Elizabeth, made a great step forward by showing in his celebrated work, ‘De magnete, magneticisque corporibus, et de magno magnete tellure, physiologia nova,’ that the two classes of phenomena, the magnetic and the electric, are emanations of a single fundamental force pervading all nature. Dr. Gilbert further discovered that many other substances besides amber possess the electric power, and that this power is easily excited when the air is dry and cool, and with difficulty when it is moist and warm. These discoveries caused great commotion in the European learned world, yet produced no further result for another half a century. In 1650, Otto von Guericke, burgomaster of Magdeburg, the inventor of the air-pump, who had studied with deep interest Dr. Gilbert’s book, succeeded in constructing a little electrical machine, composed mainly of a ball of sulphur mounted on a revolving axis. By the aid of this instrument, very rude in construction, he produced powerful sparks and flashes of electric light, and it helped him likewise to discover, first, that bodies excited by friction communicate their electricity to other bodies by mere contact, and, secondly, that there resides in electrified substances the power of repulsion as well as that of attraction.