Equipotentiol Lines of an Electric Current, 145 



June 11. 

 June 11. 



Mean. 



24-9? 

 24-95 



7-00 

 6-82 



1-985 

 1-625 



23' 



45' 



1-84 

 *7'86 



16-39 

 16-57 



23-80 27 25 

 24-27 28£ 28£ 



24-96 6-91 1-805 36° 34' 7-85 1648 24-Q3 28 27 



Keducing the three means to uniform conditions we find 



June 4 and 5. 

 June 7. 

 June 11. 



Mean. 



A 

 25 

 25 



25 



R 



6-62 

 6-26 

 6-69 



D 



1-886 

 1-825 

 1-778 



36° 

 36 c 

 36° 



E.I. 



7-60 

 7-60 

 7-60 



M. F. 

 16-6 

 16-5 

 16-1 



A' 

 25 



25 

 25 



t 



25 

 25 



25 



f 

 28 

 28 

 28 



25 



6-52 1-86 36 c 



7-60 16- 



25 28 



The observations made with weaker magnetic fields will be 

 given with somewhat ' less detail : 



No. 5. 





A 



R 



d e 



B. I. 



M. F. 



A' 



t 



*' 



June 14. 



8.21 



2-81 



500 35° 13' 



7-75 



9-44 



8-22 



28 



27 



Reduced. 



8-33 



2-80 



5-20 36° 0' 



No. 7. 



7-60 



9-38 



8-33 



25 



28 



June 14. 



837 



4-72 



1-377 36° 23' 



7-83 



9-51 



8-3 



28 



23 



June 14. 



8-20 



4-63 



1-442 36° 1' 



7-80 



9-41 



8-12 



28 



31 



Reduced mean 



.8-33 



4-57 



1-409 36° 

 No. 5. 



7-60 



9-34 



8-33 



25 



28 



June 18. 



7-34 



2-63 



4-86 34° 28' 



7-84 



8-76 



7-15 



31 



32 



Reduced. 



7-25 



2-53 



4-98 36° 



No. 7. 



7-60 



8-56 



7-25 



25 



28 



June 18. 



7-72 



451 



1-337 35° 9' 



7-85 



902 



7-55 



31° 



29° 



June 18. 



6-74 



4-11 



1-332 35° 13' 



7-85 



8-35 



6-52 



31° 



35° 



Reduced mean 



.7-25 



4-18 



1*349 36° 0' 



7-60 



8-57 



7-25 



25° 



28° 



In the above tables no corrections have been applied with 

 reference to the facts, already discussed, that the test-coil is 

 not used in just the same manner as the loops on the crosses, 

 or to the further fact that the readings of the ballistic galva- 

 nometer scale are proportional to the tangent of twice the de- 

 flection instead of being proportional to the sine of one-half 

 the deflection. In the table which follows, and which is in 

 the main derived from those going before, corrections are ap- 

 plied with these points in view. 



No. 5. 





D x (thickness R (cor- M. F. (cor- 



of cross) rected) rected) 



Int. of mag. 2 x area Area of tes 



field. of loop. coil. 



Mag. ind. 

 in cross 



D x (thickness 

 of cross) 



Int. of mag. 

 field. 



t- Mao-, ind. 

 of field. 



R (cor- 

 rected). 



16,350 280 xlO- 9 3-15 +-' 312 1*01 

 9,360 278 xlO" 9 1'83 -s- 1-79 = 1-02 

 8,540 292 xlO" 9 1-69 -4- 1*63 = 1-04 

 4,900 (July 3, '88 : no observations on tr'nsv'rsecurrent.)l -02 



•929 



11? [■- 



Am. Jour 



Sci— Third Series, Vol. XXXVI, 

 10 



No. 212.— August, 1888. 



