HISTORY OF DISCOVERY RELATIVE TO MAGNETISM. 



COMl'ILEI-) FOR Tin: IXSTITLTIOX PRINCIPALLY FROM THE "AUS DF.R NATUR." 



There are two great forces of nature everywhere present and at every 

 moment exerting tlicir influence, namely, gravitation and magnetism. They 

 are similar in many particulars, all pervading and perhaps equally powerful. 

 The magnetic phenomena of the earth, however, do not manifest themselves as 

 freely to the senses as those of gravitation, and the naturalist is obliged to em- 

 ploy refined, and, in some cases, complicated apparatus to study the laws of its 

 operation. In. this article we purpose to present to our readers a sketch of the 

 earlier discoveries relative to magnetism, and in doing so we shall also briefly 

 explain the general principles of the science. 



There is found in different parts of the earth a mineral of a dark color, 

 principally composed of iron and oxygen, which has long been an object of in- 

 terest to the ignorant as well as the learned, principally on account of the attrac- 

 tion which it exhibits for iron, and the wonderful property which it imparts to 

 steel needles of pointing toward the poles of the earth. Its composition may 

 bo expressed cheniically by th" formulse Fe + Fe2 03, being a compound 

 of the first and second oxide of iron. It is called loadstone, and occurs most 

 generally in primary mountains of gneiss ; chlorite slate, in primitive lime- 

 stone, and sometimes in considerable masses in serpentine, and in trap. It is 

 found in great quantity and purity at Ivosslay, in Sweden, in Corsica, on the 

 island of Elba, in Norway, Siberia, Saxony, Bohemia, and in the Hartz moun- 

 tains. A hill in Swedish Lapland, and Mount Pumachanche, in Chili, arc said 

 to consist almost entirely of magnetic ore. Extensive beds of magnetic iron ore 

 are found in various places in the United States, and in some of these occur 

 masses of the mineral possessing polarity ; such as those at Marshall's island, 

 Maine, at ^Magnet's Cove, Arkansas, at (iosheu, Chester county, Pennsylvania, 

 and Franklin, New Jersey. 



It has been asserted that this mineral is not magnetic in its natural condition 

 in the mine, but that the pieces only exhibit this property after having been 

 exposed to the light ; but this statement has not been verified, and is apparently 

 at variance with well-established facts. 



Th(i specimens of th*s mineral are usually so hard that they produce fire when 

 struck with steel, and it is this circumstance which renders them so difficult to 

 be worked into proper form for exhibiting in the best manner the magnetic 

 piYtperty. 



The name magnet, by which the mineral is known to us, is said to be derived 

 from ^lagnesia, a city in Asia Minor, where it was first found. The Roman 

 poet Lucretius bears testimony to this in a passage of his celebrated poem on 

 the nature of things, in which he states that the (xreeks called this stone mag- 

 net because it was found in the country of the Magnesians. 



This statement is much more probable than the account given by Pliny, who 

 derives the name of magnet from Magnes, a herdsman, who, in guarding his 

 flock on ]\Iount Ida, f'oiuul himself suddenly held fast to a magnetic rock by the 

 iron nails in his shoes and the iron point of his staff. But whatever may be 

 the origin of the names by which the magnet has been designated in different 

 languages, it is a remarkable fact that they show distinctly the idea that pre- 



