ME. G-. GOEE ON ELECTEOTOESION. 
547 
opposite in direction, were passed, commencing with one which produced a north pole 
below. The following represent the results : — 1. N. m+ 4’0; 2. S. 4'0 ; 3. N. 3 - 5 ; 
4. S. -HK 3-25 ; 5. N. »n- 2-75 ; 6. S. +« 2-5 ; 7. N. 2-7 ; 8. S. «k 2-25 ; 9. N. »+ 2-7 ; 
10. S. 2*0 ; 11. N.»+2*3; 12. S.-mkT75; 13. N.*m-2-0; 14. S.-m«T8. 
(2) After an up ward current. — Sixteen coil-currents, the first producing a south pole 
below 1. S. 2'75 ; 2. N. +« 5-25 ; 3. S. m+ 4*25 ; 4. N. +« 3-75 ; 5. S. m+ 3-70 ; 
6. N.-mk 3-25; 7. S.^3-25; 8. N.-hk3T0; 9. S.^-3-20; 10. N. -hk 3*00; 11. S.^3-00; 
12. N. 3-00 ; 13. S. 2'75 ; 14. N. -hk 3-25; 15. S. an- 2-83; 16. N.-mk 2-88. 
On comparing these results with those obtained with iron (described in Section 27), 
we find that the residual effect, both of a downward and of an upward axial current, was 
much more persistent in steel than in iron ; and we may conclude that steel possesses, 
in a greater degree than iron, a coercive power for the influence of an axial electric 
current. 
29. Influence of direction of coil-currents upon residuary effect of axial ones. 
To determine whether coil-currents producing a north pole below had a different 
effect upon the residuary influence of an axial one from those in an opposite direction, 
I made the following experiments, using the current from twelve Grove’s cells arranged 
as three : — 
(A) With a soft iron wire T75 mm. diameter. — 1st. After an up ward axial current 
from the same battery, six successive coil-currents, each producing a north pole below, 
were passed: the first produced a deflection of 2'75 mm. to the left hand, and the 
others no movement. After restoring the axial condition by several upward currents, 
six coil ones, each producing a south pole, were transmitted : the first produced a 
movement of 1*6 mm. to the right hand, and the others no effect. 2nd. After a down- 
ward axial current, six coil-currents, producing north poles below, were passed : the 
first yielded a movement of 4 mm. to the right hand, and the remainder had no effect. 
The downward axial-current influence was then restored, and six coil-currents producing 
south poles below transmitted: the first resulted in a movement of 4 - 75 mm. to the 
left hand ; the others were without effect. 
On comparing these results with those described in Section 17, page 540, it will be 
seen that the cessation of torsion was less sudden with axial currents succeeding coil 
ones than with the reverse, probably because the residuary axial condition is less stable 
than the residuary coil one, and the latter was renewed by the influence of terrestrial 
magnetism. 
(B) With a steel wire 2T7 mm. diameter. — 1st. After an upward axial current, six 
coil-currents, producing north poles below, were transmitted : the first produced a 
movement of 0-5 mm. to the left, and the others no effect. The smallness of the tor- 
sion was partly because the lower end of the wire was previously a north pole. After 
restoring the upward axial current several times, six coil ones, producing south poles 
below, were passed: the first developed a movement of 6'75 mm. to the right hand, 
4 d 2 
