Permanent Magnets. 



193 



determined by swinging the magnets in the earth's field. The 

 results obtained are summed up in the table on page 184. 



The second series of experiments shows that the proportional 

 change in distribution of magnetism due to change of tempera- 



Magnet B. 



Distance 



from 

 center of 

 magnet. 



15-20 

 13-03 

 10-86 

 8-68 

 6-51 

 4-34 

 2-17 







2-17 



4-34 



6-51 



8-68 



10-86 



13-03 



15-20 





Change in 



Distribu- 



I 14 



199-5 



Distribu- 

 tion at 14° 



distribu- 

 tion. 



tion at 

 99°-5. 



Induction 

 at 14°. 



Induction 

 at 99° -5. 



61-0 



- 3-9 



+ 57-1 



258- 



242- 



359-5 



— 39-6 



+ 3199 



1777- 



1594- 



227*6 



— 15-1 



+ 212-5 



2738- 



2491- 



159-7 



— 6-0 



+ 153-7 



3413- 



3141- 



139-4 



— 3-4 



+ 136-0 



4002- 



3716- 



108-1 



- 2-1 



+ 106-0 



4458* 



4163- 



81*4 



- 1-5 



+ 80-0 



4802- 



4501? 



43-5 



— o-i 



+ 43-4 



j 4986- 

 ( 4950- 



j 4685- 

 ( 4650- 









3-6 



+ 0-7 



+ 4-3 



4965- 



4668- 



— 36-2 



+ l'l 



— 35-1 



4812- 



4520° 



— 79-8 



+ 2-0 



- 77-8 



4475- 



4191* 



— 128-3 



+ 2-4 



-125-9 



3933- 



3659- 



— 188-6 



+ 6-6 



— 182-0 



3136- 



2890- 



-266-3 



+ 19-0 



— 247-3 



2011- 



1845- 



— 406-4 



+ 35-4 



— 371-0 



294- 



277- 



— 69-7 



+ 4-1 



— 65-6 







I] 4—199- 



ITT - 



062 

 103 

 090 

 079 

 071 

 066 

 062 



060 



060 

 060 

 063 

 069 



078 

 082 

 057 



ture is greatest at the ends and least in the middle of the mag- 

 net. A glance at the tables given above, or at the curves in 

 fig. 3, will show this. This is different from the result obtained 

 by Poloni, who found the proportional change sensibly con- 

 stant throughout the magnet. It could not be expected that 

 the small difference noticed here could be detected by his 

 method, which consisted in measuring two large quantities and 



