Dr. C. Froinme on the Magnetism of Steel Bars. 193 



With these data Gr, and from it k and K, can be calculated 

 as soon as the angles a and /3 are ascertained by observation. 



On every occasion three series of observations were made 

 for this purpose, as before and after each observation with the 

 ellipsoid inserted the angle /3, corresponding to the direct in- 

 duction-current, was found by turning the helix alone. Each 

 of the three series consisted of two sets of twelve return-points 

 of the galvanometer-needle, half belonging to one, and half to 

 the other extremity of the multiplication-arc. The return- 

 points were taken successively in threes ; and from the eight 

 resulting triples the multiplication-deflection was calculated on 

 the scale. 



As an example, I give in extenso the notes of one observa- 

 tion : — 



0. 



Monday, March 2, 1874, 



evening. Temperature 



Ellipsoid I. 5. Inducing fore 



3 the horizontal compone 





Helix. 



a. b. 





a. b. 



784-3 740-3 





785-3 741-0 



784-6 740-6 





785-0 740-8 



784-9 740-8 





785-3 741-0 



784-9 740-7 





785-1 741-0 



785-0 740-8 





785-0 741-0 



785-0 741-0 





785-0 741-1 



a-b. 





a— b. 



44-15 





44-15 



44-2 





44-4 



44-25 





44-05 



44-1 





44-0 



44-175 





44-15 



a 



-b 



-22-0813. 



Helix plus Ellipsoid. 



b'. 



a\ 



711-6 



814-9 



711-2 



814-8 



711-0 



814-7 



710-9 



814-7 



710-7 



814-8 



711-0 



814-8 



hilMag. S.5. 



Vol. 1. 



No. 3. 



b\ 



a'. 



711-0 



814-6 



710-8 



814-5 



710-5 



814-2 



710-2 



813-8 



710-1 



813-8 



710-1 



813-8 



March 1876. 



