190 Loomis — Effects of Changes of Temperature on 



M: 



\~^ 



nd. 



To this value the following correction was added : If AB in 

 figure 4 is the length of one of these divisions of the magnet, 

 and CD a part of the distribution curve supposed to be straight, 

 then the area ABDC represents the number of lines of induc- 

 tion issuing from the magnet in the length AB. Let F be the 

 center of gravity of the triangle CED. It is evident that the 

 portion of the distribution represented by the triangle should 

 be m ultip lied by the abscissa of F, not of H, therefore a correc- 

 tion ^> area CEDxGrH was added to the summation already 



given. From this calculation the following results were 

 obtained : 



Magnets. A. B. 



Moment at 14° C. 2298 2060 



Moment at 99*°5 C. 2140 2018 



Loss. 158 142 



M 14 

 M 99 , 

 M 14 -M 9 

 M,.-M„ 



M, 



Proportional loss. 



Intensity at 14° C. 

 Intensitv at 99*°5 C. 



0-0687 



322 

 300 



0-0689 



289 

 283 



The magnetic moments were also determined by the method 

 used in the first part of this investigation with the following 

 results : 



Magnets. 

 Moment at 14° C. 

 Moment at 99°-5 C. 

 Loss. 



5J" 



M 99 - 6 

 M 14 -M c 



M. 



Proportional loss. 



Intensity at 14° C. 

 Intensity at 99°-5 C. 



A. 



B. 



2359 



2091 



2197 



1947 



166 



146 



0686 



0-0687 



339 



298 



316 



277 



The difference between these two sets of values is consider- 

 able, amounting to two per cent in the case of magnet A. 

 This may be due to the fact that only an approximation could 

 be made to the moments of inertia of the magnets because of 

 the holes in the ends, where a slight er»or would affect the 

 result materially, as the distance from the center was above 

 15 cm . The moments of inertia were calculated by dividing the 

 magnet into two parts, an inner core and an outer shell extend- 

 ing bevond the core at both ends. On the other hand, it is to 



M M 



be noticed that the ratios — ^ 99 ' 6 differ by less than one part 



14 



in 300. In this ratio the moment of inertia of the magnet is 

 eliminated. 



