240 SEC. 9. MAGNETISM. 



of the needle produced by the magnet when open, and when more or less 

 closed. 



See the memoir of Prof. Van der Willigen, which will soon appear in the 

 Archives du Musee Teyler. 



1109. Great Artificial Magnet, forged and magnetised in 

 1850 by Messrs. Van Wetteren and Logemann, according to the 

 directions of Dr. Elias, whose property it is. 



Teyler Foundation, Haarlem. 



Newly magnetised at Teyler's Museum. 



Weight - 28 kilograms. 



Primitive force - - 260 



Permanent force - - 200 



1109a. Large Artificial Magnet made of thin Plates. 



M. Jamin, Paris. 



1110. Photograph of a Horse-shoe Magnet, made by 

 Johann Dietrich, of Basle, in 175,5. 



Professor Hagenbach-Bischoff, Director, The Physical 

 Institute in the Bernoullianum, Basle. 



1111. Permanent Bar Magnets (pair of), in case. 



James Hmv fy Co. 



1112. Compound Horse-shoe Magnet. James How $ Co. 



1112a. Series of Permanent Magnets, bar form, in 

 wooden cases for students. Harvey, Reynolds, and Co. 



1113. A '< Logemann's " Magnet, being a powerful bat- 

 tery of steel-plate magnets. Frederick Guthrie, F.R.8. 



1113a. Magnets by M. Jamin. M. Breguet, Paris. 



III. ELECTRO-MAGNETS AND ELECTRO-MAGNETIC 



ENGINES. 



1114. Saxton's Magneto-Electric Machine. Copy of the 

 original machine made by Mr. Saxton, and exhibited by him 

 before the third meeting of the British Association, held at Cam- 

 bridge in the year 1833." John O. N. Ruttcr, F.R.A.S. 



This machine was made specially for the contributor by Mr. Saxton, 

 immediately after the meeting at Cambridge, and has been in his possession 

 ever since. It is capable of producing sparks, shocks (through the tongue), 

 and decomposes water. It also reproduces the ordinary phenomena of electro- 

 magnetism. 



The machine is described in Daniell's " Introduction to Chemical Philosophy," 

 1843, p. 585, sec. 873. 



