CHAPTER III.

OERSTED'S DISCOVERY AND THE ELECTRO

MAGNET.

ALL the world would doubtless be glad to unite in doing honor to the author of one of the finest discoveries of all time, could his identity be revealed. There is little chance, however, that the discoverer of the magnet, or the discoverer and inventor of the magnetic needle, will ever be known by name, or that even the locality and date of the discovery will ever be determined. The first observer of the attractive power of certain ores of iron may or may not have found their tendency to assume a certain direction when freely suspended. The transfer of this power and tendency to pieces of iron and steel, and thus the invention of the mariner's compass, constitutes an advance upon the observed attraction of the ore so considerable as to challenge the admiration of those most skilled in modern methods of research.

It has been claimed by Humboldt and others that the earliest known use of the magnetic

needle was among the Chinese, in whose history it is referred to at a date as early as twenty-six hundred years before the Christian era. It is not there described as a mariner's compass, but seems to have been used to guide armies over the great plains of the interior. It is represented as having been carried in a wagon, and consisting of the figure of a man whose extended arm constantly pointed towards the south. It is interesting to note that among the Chinese the needle was described as pointing to the south, precisely as among Western nations it is spoken of as indicating the north. The custom of China in this respect prevailed also in Japan. Although the Greeks and Romans were aware of the attractive power of the magnet, they were evidently ignorant of its polarity, or directive power. Unfortunately, nearly all references to it in the literature of that period are so undoubtedly fabulous that they are of little real value.

The name "magnet" is unquestionably derived from Magnesia, a city in Asia Minor, where the first specimens were probably found; although Pliny derives it from Magnes, a herdsman who found himself rooted to a magnetic rock by the nails in his shoes and the iron points of his staff. Magnets were made use of in the ceremonies of the temple, and by their

aid statues of the gods were suspended in midair. A statue of Venus, made from a magnet, held an iron statue of Mars, suspended; and every one knows the story of Mahomet's coffin, which "soared in a sanctuary built of magnetic stones." The tradition of a magnetic mountain at sea, over which a ship with iron bolts and nails could not sail in safety, is found in many languages. In Japan it is a popular belief that a magnet loses its power a short time previous to an earthquake, and it has been used as a prophetic seismoscope. The magnet has also been credited with extraordinary medicinal, and, indeed, moral powers. In addition to its power to cure various diseases, it was thought to possess the very desirable quality of enabling its owner to win friendship and love, to succeed in business, and to discover the secret feelings of others. It was solemnly affirmed to be capable of revealing whether a bride had accepted a husband from motives of affection, or from considerations of a pecuniary nature.

Even brief reference to such absurdities would be inexcusable, were it not for the purpose of inviting attention to the fact, that, as with electricity, the present age is not free from impositions of a similar character. Only a few years ago, in a city which is the seat of a university and sundry other educational establishments,

the writer happened upon a dealer who was doing a thriving business in the sale of small fragments of loadstone, to be used for psychical rather than physical research.

The use of the compass does not appear to have been known among Western nations before the twelfth century. The tremendous extension of human knowledge through the extension of human intercourse, which rapidly followed during the succeeding centuries, must be largely attributed to its use; and a feeling of astonishment results from a contemplation of the fact that the Chinese, according to their own records, were in possession of the secret of ocean navigation for four thousand years previous to the time of Columbus, and yet almost no use was made of it.

As stated in a previous chapter, the magnet and magnetism received their first scientific treatment at the hands of Dr. Gilbert. During the two centuries succeeding the publication of his work, the science of magnetism was much cultivated. The distribution of the magnetism of the earth was investigated, and methods of making artificial magnets by the "touch" of the natural were experimented upon, and considerable improvements devised. The development of the science went along parallel with that of the science of electricity, as outlined in

the first chapter, although the latter was more fruitful in novel discoveries and unexpected applications than the former. It is not to be imagined that the many close resemblances of the two classes of phenomena were allowed to pass unnoticed. Both had been known from the earliest times; both exhibited attraction, both repulsion, and under decidedly similar conditions. In both cases the law of attraction and repulsion was that of inverse squares. But nearly all bodies were known to be capable of electrification, while hardly more than one or two could be magnetized. Electrification could be produced under almost all circumstances, and electricity made to appear where none apparently existed before. Magnetism had to be borrowed; and although the touching or inducing magnet lost none of its power in establishing polarity in a piece of steel; and while it was possible, by proper manipulation and combination, to produce a magnet of greater strength than that used as the source, there was no known process by means of which the condition of magnetization could be created from the beginning.

Notwithstanding these differences, there was enough resemblance to suggest an intimate relation; and the connecting link was sought for by many eminent philosophers during the last