ON A NEW DIAMAGNETIC ATTACHMENT TO THE LANTERN, 

 WITH A NOTE ON THE THEOEY OF THE OSCILLATIONS 

 OF INDUCTIVELY MAGNETIZED BODIES 



[American Journal of Science [8], IX, 357-361, 1875] 



1. DESCRIPTION OF APPARATUS 



Some time ago, in thinking of the theory of diamagnetism, I came 

 to the conclusion that apparatus of large size was by no means neces- 

 sary in diamagnetic experiments, and on testing my conjectures experi- 

 mentally, I was much pleased to find that they were true. So that for 

 more than a year I have been in the habit of illustrating this subject 

 to my classes by means of a small apparatus weighing only about a 

 pound or two, which I place in my lantern and magnify to a large size 

 on the screen. 



The effects obtained in this way are very fine and are not surpassed 

 by those with the largest magnets; and we are by no means confined, 

 to strongly diamagnetic substances, but, with proper care, can use any- 

 thing, even the most feeble. The apparatus which I used consisted of 

 a horseshoe electro-magnet, made of an iron bar half an inch in diam- 

 eter and about ten inches long, bent into the proper form, and sur- 

 rounded with four or five layers of No. 16 wire. But the following 

 apparatus will, without doubt, be found much more convenient. It can 

 be made of any size, though the dimensions given will probably be 

 found convenient. 



d d 



FIGURE 1. 



The apparatus is represented in Fig. 1. To a straight bar of iron h, 

 7 in. long, in. thick, and f in. wide, are attached two pieces e e of 

 the same kind of iron by two set screws g g, which move in slots in the 



