288 HISTORY OF DISCOVERY ■ RELATIVE TO MAGNETISM. 



contact with the poles of the magnet. Some plausibility was, however, given 

 to these stories, because magnets have been obtained which could sustain a 

 heavy weight of iron when the latter was in contact with the poles of the latter. 

 Thus, Wolf mentions examples of natural magnets which could support, by 

 means of an armature, from sixteen to forty times, and even three hundred and 

 twenty times their own weight. Dufay had in his possession a magnet of nine 

 pounds in weight, which could hold seventy-six pounds. As a general rule, 

 smaller magnets can support comparatively more than larger ones. Such, for 

 example, as weigh from twenty to thirty grains will sometimes support fifty 

 times their weight, whilst magnets Aveighing two pounds scarcely ever sustain 

 ten times their own weight. According to Dr. Martin, Sir Isaac Newton had 

 a magnet which was set in a finger-ring, and which, though only of three 

 grains in weight, could hold seven hundred and forty-six grains. In the philo- 

 sophical cabinet of the university at Dorpat there is a magnet weighing forty 

 pounds, including the armature and a copper case, which is able to sustain 

 eighty-eeven pounds. A still larger one is found in Tyler's museum, which 

 Aveighs three hundred and seven pounds, the armature inclusive, and holds 

 more than two hundred and thirty pounds. Not less considerable was the 

 mngnet which John 1, King of Portugal, received as a present from the Em- 

 peror of China, which weighed a little over thirty-eight pounds, and was able 

 to support tAvo hundred and two jiounds. 



But to return to the direct continuation of our history, we should state that a 

 tradition of a A^ery ancient date still exists in China respecting a mountain of 

 magnetic ore rising in the midst of the sea, the intensity of attraction of Avhich 

 is so great as to draAv the nails and iron bolts Avith Avhich the planks of a ship 

 are fastened together from their places Avith such force as to cause the vessel to 

 fall to pieces. This tradition is not confined to China, but is very general 

 throughoxit all Asia; and the Chinese historians assign to the mountain a spe- 

 cific place Avhich they call Tchang-hai, the southern sea, between Tonqiiin and 

 Cochin- China. Ptolemy, also, in a remarkable passage in his geography, 

 places this mountain in the Chinese seas. In a Avork attributed to St. Ambrose 

 there is an account of one of the islands of the Persian Gulf, called Mammoles, 

 in Avhich the magnet is found, and the pi-ecautions necessary to be taken in 

 building ships Aviihout iron to navigate in that vicinity is distinctly specified. 

 In tAA'o passages of the Avork of the Arabian geographer, Chenf-Edrlu, and in a 

 remarkable one in the apocryphal Arabian translation of the "Treatise on 

 Stones," attributed to Aristotle, the existence of this mountain is again specifi- 

 cally stated. A reference to it also occurs in Vincent de Beauvais, a French 

 Avriter, Avho had been in the holy Avars ; and, after his time, in the works of a 

 groat number of European writers. 



A circumstance remarkable enough is, that the Chinese Avriters place this 

 magnetic mountain in precisely the same geographical region in Avhich it is 

 stated^ to exist by the author of the voyages of Sikbad the Sailor. This has 

 been justly lookod upon as a confirmation of an opinion as to the oriental 

 origin of a great number of the talcs, half fiction, half fact, Avhich are so univer- 

 sally diffused among the legendary literature of every country as to appear 

 indigenous in each of them. We would not, however, go to the extent of saying 

 that all our nursery fictions are derived from the east, though it cannot be 

 denied that a great number of them are of oriental origin.- 



It is not surprising that the magnet Avhich exhibited such extraordinary 

 physical effects should have attributed to it Avonderful moral and medicinal 

 powers. Accordingly avc find the belief entertained that it could enable its 

 possessor to gain the confidence of princes, the affection of Avomen, and to 

 secure conjugal love, as Avell as cure the gout, the headache, and the heartache. 

 ,ln a little book of secrets, extracted from Albertus Magnus and others, Avas one 

 to ascertain Avhether your sweetheart did really love you, and another to dis- 



