II. PERMANENT ARTIFICIAL MAGNETS. 239 



SECTION 9. MAGNETISM. 



WEST GALLERY, GROUND FLOOR, ROOM F. 



I. NATURAL MAGNETS. 



1106. Great Natural Magnet; the largest known. See 

 Lament, " Handbuch des Magnetismus," 1867, p. 107. 



Teyler Foundation, Haarlem. 



Weight, with the armature - 152 kilograms. 



Force - - - 114 



1107. Natural Magnet, mounted in brass case, with steel 

 poles, and soft iron keeper. Elliott Brothers. 



HO7a. Natural Loadstones (two), Russian, in perforated 

 and painted metal cases. Bennet Woodcraft, F.R.S. 



1107b. Siberian Loadstone and Spark Apparatus. This 

 was the loadstone employed by Faraday in his experiments on 

 magneto-electric induction, from which he first obtained the 

 induction spark. (See Exp. Researches, vol. n.) 



Museum of King George III., King's College. 



II. PERMANENT ARTIFICIAL MAGNETS. 



1108. Collection of Artificial Magnets, lately forged by 

 Mr. Van Wetteren, and magnetised at Teyler's Museum. 



Teyler Foundation, Haarlem. 



A. Single magnet, weight 2 '17 kilogr. ; greatest primitive force, 51*3 

 kilogr. ; permanent force, 35 9 kilogr. 



B. Compounded magnet. No. 3,053. Weight, 1-52 kilogr.; greatest 

 primitive force, 36 '4 kilogr. ; permanent force, 27 7 kilogr. 



C. Two single magnets. No. 3,003. Weight, 0-51 kilogr.; greatest 

 primitive force, 19 '5 kilogr.; permanent force, 12*4 kilogr. No. 3,005. 

 Weight, 0-52 kilogr. ; greatest primitive force, 18-6 kilogr.; permanent 

 force, 13 '7 kilogr. 



A third open keeper with moveable side plates. 



The box, C, forms a school apparatus, to demonstrate the effect of mutual 

 contact of the magnets, and of the constitution of the keeper, on the distribution 

 of free magnetism, on the weight that can be suspended, and on the deflections 



