516 



PROFESSOR KNOTT ON SOME RELATIONS BETWEEN 



Table IV. — Nickel Wire, 76 cm. long, 0*86 mm. in diameter' — continued. 



Current in 

 Amperes, 



Twist. 



Intensity. 



Lag. 



Area +• ir. 



Range. 



020 



-225° 



175 



175 







- 46 



351 





-180 



168 



162 



+ 6 









- 90 



+ 111 



117 



- 6 













- 27 



4 45 



- 72 









90 



-119 



- 95 



- 24 









+ 180 



-163 



-166 



+ 3 









+ 225 



- 



L76 











0-46 



-225 



260 



260 







-140 



521 





-180 



243 



251 



- 8 









- 90 



+ 142 



205 



- 63 













- 82 



+ 60 



-142 









+ 90 



- 212 



-170 



- 58 









+ 180 



-254 



-252 



- 8 







0-92 



+ 225 



-261 











-225 



284 



284 







-182 



567 





-180 



273 



278 



- 5 









- 90 



-179 



246 



- 67 













+ 112 



+ 113 



-225 









+ 90 



-244 



-182 



- 62 









+ 180 



-277 



-272 



- 5 









+ 225 



-283 











1-62 



-225 



302 



300 



+ 2 



-261 



604 





-180 



283 



296 



- 13 









- 90 



+ 160 



+ 270 



-110 













-166 



+ 149 



-315 









+ 90 



-273 



-195 



- 78 









+ 180 



-300 



-292 



- 8 









+ 225 



-303 











2-73 



-225 



311 



311 







-285 



625 





-180 



295 



306 



- 11 









- 90 



+ 179 



283 



-104 













-183 



+ 175 



-358 









+ 90 



-287 



-198 



- 89 









+ 180 



-311 



-303 



- 8 









+ 225 



-314 











18. Magnetic Lagging and Priming. — The principal features embodied in this table 

 are indicated in figs. 1-5 of PL IV. Figures 1, 2, and 3 are examples of complete cycles 

 for three different ranges of twist. The twists are taken as abscissa? and the intensities 

 as ordinates. The intensity scale is the same for all, but in fig. 3 the twist scale is con- 

 tracted for convenience of representation. The number placed at the left-hand cusp of 

 each cyclic graph is the current corresponding ; so that the graph can be easily associated 

 with the numbers in the table. The sign + or — at the right-hand cusp is an indication 

 of the manner in which the graph is gone round ; the positive sign being clockwise 

 (lagging), and the negative counter-clockwise (priming). Fig. 1 gives four out of the 

 eight distinct experiments for the twist cycle ± 90°. All show positive lagging. Fig. 2 

 gives three out of the six experiments for the twist C3^cle ± 180°. For the smallest 



