154 DR. FARADAY’S EXPERIMENTAL RESEARCHES IN ELECTRICITY. (SERIES XXIX.) 
3221. A soft iron bar, now applied in the first, second and third positions instead 
of the magnet A, raised DE to the following values respectively, 16°'24, 16°'43, 
and 18°. 
3222. When an ordinary bar-magnet was employed instead of the hard magnet 
D E, great changes took place. Thus a bar B, corresponding to bar A in size and 
general character, was employed in place of the hard magnet. Alone, B had a power 
of 14°'83, but when associated adversely with A, as in position 3 (3218.), its power 
fell to 7°‘87j being reduced nearly one-half. This loss was chiefly due to a coercion 
internally, and not to a permanent destruction of the state of magnet B ; for when 
A was removed, B rose again to 13°'06. When B was laid for a few moments 
favourably on A and then removed, it was found that the latter had been raised 
to a permanent external action of 15°'25. 
3223. A very hard steel bar 6 inches long, 0*5 broad and OT in thickness, given to 
me by Dr. Scoresby, was magnetized and then found, by the use of the loop, to have 
a value at ray galvanometer of 6°'88 (3189.). It was submitted in position 2 to a 
compound bar-magnet like D E, having a power of 1 1°‘73, or almost twice its own 
force, but whether in the adverse or the favourable position, its power was not sensi- 
bly altered. When submitted in like manner to a 12-inch bar-magnet having a force 
of 40°'21, it was raised to 7°'53, or lowered to but here the dominant magnet 
had nearly six times the power of the one affected. 
3224. The variability of soft steel magnets, both in respect of their absolute degree 
of excitation or charge, and also of the disposition of the force externally and infer- 
nally, when their degree of excitation may for the time be considered as the same, is 
made very manifest by this mode of examination ; and the results agree well with 
our former knowledge in this respect. It is equally manifest, that hard and invariable 
magnets are requisite for a correct and close investigation of the disposition and 
characters of the magnetic force. A common soft bar-magnet may be considered as 
an assemblage of hard and soft parts, disposed in a manner utterly uncertain ; of 
which some parts take a much higher charge than others, and change less under the 
influence of external magnets ; whilst, because of the presence of other parts within, 
acting as the keeper or submagnet, they may seem to undergo far greater changes 
than they really do. Hence the value of these hard and comparatively unchangeable 
magnets which Scoresby describes. 
3225. From these and such results, it appears tq me, that with perfect, unchange- 
able magnets, and using the term line of force as a mere representant of the force as 
before defined (3071. 3072.), the following useful conclusions may be drawn. 
3226. Lines of force of different magnets in favourable positions to each other 
coalesce. 
3227 . There is no increase of the total force of the lines by this coalescence ; the 
section between the two associated poles gives the same sum of power as that of the 
section of the lines of the invariable magnet when it is alone (3217.)* Under these 
