332 Mr. H. A. Rowland on the Magnetic Permeability 



K. 



3. 







12-5 

 18-75 

 22-5 

 25 



-140 

 205 

 455 

 703 



1206 



3802 

 2833 

 2269 

 1835 



K 



on • 3+25k+140 

 " 25sm 21-9 ' 





I have not as yet obtained a complete curve of iron at a high 

 temperature ; but as far as I have tried, it does not seem to be 

 affected much, at least for high magnetizing-powers. I have, 

 however, found that the maximum of magnetization of iron 

 decreases about 2 per cent, by a rise of temperature from 15° C. 

 to 222° C, while that of nickel decreases 22'7 per cent. 



The experiments which I have made with cobalt do not seem 

 to be so satisfactory as those made with nickel and iron. There 

 are some things about them which I cannot yet explain ; but as 

 they are the only exact experiments yet made on cobalt, they 

 must possess at least a transient value. The difficulties of getting 

 a good cobalt-curve are manifold, and are due to the following 

 properties — (1) its small permeability, (2) its sensitiveness to 

 temperature, and (3) its property of having its permeability 

 increased by rise of temperature at all magnetizing-powers within 

 the limits of experiment. The following are the results with 

 No. I. :— 



Table IV. 



Cast Cobalt, normal, at 5° C. 



Experiments made November 27, 1873. 



fr 



SB. 



p. 



T. 



P. 



| 



3- 



K. 



Ob- 



served. 



K. 



Calcu- 

 lated. 



Error. 



49-33 



4303 



87-24 



3702 



601 



3385 



6-86 



6-75 



-•11 



58-83 



5608 



95-32 



4526 



1082 



441-6 



7-51 



7-44 



-•07 



76-47 



8409 



109-95 



6175 



2234 



6631 



8-67 



8-79 



12 



93-15 



11623 



124-8 



7826 



3797 



9175 



9-85 



9-81 



-•04 



113-0 



14993 



132-7 



9805 



5188 



1193-1 



10-48 



10-44 



-•04 



1293 



17439 



1349 



10580 



6859 



1387-8 



10-66 



10-72 



•06 



159-4 



22309 



1400 



14090 



8219 



1775-3 



11-06 



11-00 



-•06 



189-0 



26769 



141-6 



16260 



10509 



2130-3 



1119 



10-97 



-•22 



219-6 



30580 



139-3 



18200 



12380 



'24335 



11-01 



10-83 



-•18 



264-7 



35525 



134-2 



21120 



14405 



j2827-0 



10-60 



10-50 



-•10 



3511 



43421 



123-7 



25670 



17751 



3455-0 



976 



9-73 



-•03 



4000 



46640 



116-6 



27830 



18810 



37115 



9-20 



9-34 



•14 



5521 



55410 



100-4 



34090 



21320 



44090 



7-91 



8-16 



•25 



7321 



63400 



86-6 



39850 



23550 



50450 



6-81 



6-93 



12 



999-8 



71800 



71-8 



47310 



24490 



5714-0 



5-63 



5-55 



-•08 



1471 



80770 



54-9 



55870 



24900 



64300 



8160 



4-29 



3-98 

 .0 



-•31 



46 



