522 



PROFESSOR KNOTT ON SOME RELATIONS BETWEEN 



Table showing the effect of decreasing and increasing Cycles of Twist {diameter of 



Nickel Wire =1 '3 mm.). 





203 



203 



1-94 



1-86 



1-84 



1-84 



1-77 



1-75 



1-72 



1-72 



1-72 



1-72 



-135 



















tap. 





tap. 





tap. 



- 90 



- 24 























- 1 



+ 5 



- 45 



-140 



-24 

















+ 2 



- 1 







- 30 







+ 24 



- 1 











- 1 



+ 29 



- 5 







- 15 









+ 84 









+ 73 



-12 











- 5 













+ 1 



















-297 



-91 



+ 94 



+ 83 



+ 37 



+ 4 



+ 86 



-21 



+ 120 



-82 



-48 



-281 



+ 5 





























+ 15 









+ 23 









+ 24 



- 3 











+ 30 







+ 10 



















+ 12 



- 6 







+ 45 



-119 



-13 





























+ 90 



- 21 































+ 135 





























Range 



526 



501 



416 



331 



166 



41 



328 



399 



409 



448 



497 



494 



This table contains in epitome many of the features that have been discussed in the 

 preceding paragraphs. The new point to note is this after-effect of the second order, in 

 virtue of which the positive lagging is greater and the negative lagging is less when the 

 corresponding twisting is approached from lower values than when it is approached 

 from higher values. 



22. Results for Iron. — We now pass to the consideration of the iron, the results for 

 which are given in Table VII. , constructed after the fashion of Table VI. Since, however, 

 it was necessary to work up to considerably higher twists, it has been found more con- 

 venient to express the half-twists as submultiples or multiples of ir. As in Table VI. , 

 the numbers marked with an asterisk belong to experiments in which the wire was 

 vigorously tapped throughout its length at each stage of observation. 



Table VII. — Iron Wires. 



Diameter in 



Current in 



Half-Twist in 



Area 



Range of 



mm. 



Amperes. 



Multiples of ir. 



IT. 



Intensity. 



0-86 



0-077 



1 



19 



60 









14* 



112* 





0-151 





51 



138 









45-5* 



208* 





0-276 





78-5 



212 





0-48 





102-3* 



274* 





0-87 





139-5 



365 





1-48 





151-6 



401-5 





2-58 





131 



377 





3-80 





121-8 



350-5 





3-50 





84-4* 



544-5* 





0-14 



1 



102 



260 





0-38 





280 



460 





0-70 



>) 



353 



586 



