198 Dr. Faraday’s Experimental Researches in Electricity. 
2674. It is therefore at these two points that the commutator 
should change, if adjusted to produce the greatest effect at the 
galvanometer by the currents excited in the experimental helix, 
through the influence of, or in connection with, currents of in- 
duction produced in the core; and experiment fully justifies this 
conclusion. If the length of the journey from the stop out to 
the stop in, which is 2 inches (2643. 2644.), be divided in 100 
parts, and the dominant magnet be supposed to be on the right 
hand, then such an expression as the following, 50/50, may rep- 
.  Yesent the place where the commutator changes, which i in this 
, ~  jilustration would be rida in the to and from motion, or at 
*.~ .the a of rg velocity. 
io 26 ial of various = porte of the eocknon aaa I 
*_ eopper core. On the whole, and hak many experiments, I con- 
clude that with the given strength of ae er 58 distance aA 
of the + hago core when at the nearest from the magnet, 
as 
; cS change. 
2676. From what has been said befor (2667.), it will a seen ~ 
oat both:in theory and experiment these are the points in which 
anny thé effect of any polarity, magnetic or diamagnetic, would be ab- 
os “solutely nothing. Hence the power of submitting by this ma- 
“\° * ‘chine metals and other bodies to experiment, and of eliminating 
. we e eflects’of magnetic polarity, of ane 2 polarity, and of 
iductive action, the one from the others: for either by the com- 
at BE Thu itator or by the direction of the Piothy: they can be separated ; 
Pooke a furthey, they can also’ be combined in various ways for the 
=" : tery pose of elucidating sae Jonas a action. Be) 
mi. 2677, ; For let the arr ee 
rns, 
2 % + 
‘ On 8 é a : ~ 
4a deflection of the needle always: ii’ Sie direction ; - 
when the ends a and 6 have pst aud d, ‘ake ~ 
fe preg te’ lirect at i. : 
ee ee 
a 3 
