544 
ME. Gr. GOEE ON ELECTEOTOESION. 
nor even detorsion, by influence of the weight occurred. It is evident from these results 
that the torsions produced by alternate coil and axial currents are affected by mechanical 
pull, and are therefore related to the forces of cohesion (compare also Section 42). 
23. Relation of coil-current torsions to electric sounds. 
To ascertain this I employed the same iron wire &c. as before (see Section 12). 
Coil-currents in each direction were tried, both in succession and alternation, and coil- 
currents succeeding axial ones were also employed. In every instance a coil-current 
acting alone produced a sound, both at its commencement and termination, the former 
being the loudest and the latter more metallic ; and by repetition of the current in the 
same direction the two sounds were more feeble. Coil-currents succeeding axial ones 
also produced sounds, both at their commencement and cessation, the former being in 
every case louder and more dull, and the latter feebler and more metallic (see also 
Section 24) ; and by repeating the coil-current in the same direction the two sounds 
were more feeble. In each case, with coil-currents alone, the louder and duller sounds 
accompanied the large inelastic torsions, and the feebler and more metallic ones 
occurred with the small elastic movements ; but the sounds produced by repeating a 
doil-current in the same direction did not appear to be weakened in proportion to the 
degree of diminution of magnitude of the torsions. These results are generally similar 
to those obtained with axial currents (see Section 12), and similar general conclusions 
to those stated on page 536 may be drawn from them. (For sounds produced by simul- 
taneous and divided currents, see Section 36, p. 555.) 
24. Does a red heat destroy residual axial-current effect \ 
A soft-iron wire 1*55 mm. diameter was placed in the helix, and a series of alternate 
coil-currents (producing south poles below) and downward axial ones transmitted, in 
order to ascertain the average amount of movement produced by the coil-currents. 
The coil-current movements were all detorsions (see Section 21) to the right hand, and 
averaged 5T mm. Ten downward axial currents were then transmitted to impart the 
axial state. The wire was now heated to redness throughout its length whilst in the 
magnetic meridian, and allowed to cool in that position. On replacing it in the helix, 
and passing a single coil-current in the same direction as before, not the slightest 
torsion occurred, although a strong metallic sound was heard in the wire on making 
contact. The wire was again similarly imbued with the axial influence, then heated to 
redness, and cooled whilst in a horizontal position at right angles to the magnetic 
meridian. On again replacing it in the helix and passing a coil-current as before, a 
torsional movement, amounting only to -5 mm., occurred, and a dull thud was heard in 
the wire on making contact. It is evident that the residuary axial-current state is 
destroyed by a red heat, and is but little restored by cooling the wire whilst in a 
direction at right angles to the terrestrial magnetic meridian. 
As electrotorsion is closely related to the magnetism, cohesion, and mechanical states 
