14 
REPORT — 1851. 
experiments to ascertain the effects of transverse magnetization on portions of i 
circuit of soft iron or of steel wire; and to test differences of thermo-electi 
properties in different directions in a magnetized mass, which the author ant e 
pated from certain considerations more fully explained in a theoretical paper on 
thermo-electricity in crystals recently communicated to the Royal Society of bl n- 
burgh. Experiments on the effects of temporary and permanent strains, byteww. I 
and by either lateral or longitudinal compression, on various metals were descntH 
The thermo-electric effects of temporary tension in the cases of cupper «tkI im 
which had been communicated by the author to the Royal Society in May ( ,,an ‘' '• 
current from stretched to unstretehed through hot, in copper, and from mitre t' 
to stretched through hot, in iron), were verified by means of a new form o 
tus so simple that he hoped to be able with great ease to test the correspo.v.- 
property for a great variety of metals. In those two cases the permanen 
electric effects of permanent extension by drawing the wires through a P j 
which had been discovered by Magnus, were the reverse of temporary ^ 
temporary extension discovered by the author of the present paper. ^ I 
electric effects produced by permanent lateral compression, always ‘ ^ 
with those of permanent longitudinal extension, were tested in *“ eca ? _ cr ’p, | 
cadmium, and lead, and were found to be the same as in the case 0 PIV ^ j 
current was from unstrained to strained through hot in each case. ^ .... I 
results agreed, while others appeared at variance, with what roig , eW , 
pected from Magnus’s careful experiments; but os the aatbor , lectnCc ff. 
cycle of experiments which he proposed to make on the tnpr • ^ - otl 
either tempoiary or permanent, of longitudinal extensions, lac . aQV ia” •' 
longitudinal compressions, and lateral extensions, he refraine 
remarks on the present occasion. 
opinion in a series of memoirs recently published in Poggenaomj » n «b 
affirms that diamagnetic bodies possess a polarity the same as a this couo' r 
deavours to bring the phenomena into harmony with this vie • .p| inia5 on, nC 
°n the contrary, we have Prof. Faraday, and it was behoved, n 0 „ the I*; 
of whom are prepared to admit the existence of any polarity f .j, e difficult' 
of diamagnetic bodies. These divergences were a sufficient prooi 
the subject, and the necessity of caution in dealing with it, . _ sCC ndi c ? 
thought it well to commence with the fundamental phwnomcu » n£f (0 c i; - 
them to the more complicated, to endeavour to obtain, by stri _ prta iu bodu-- - 
ment. a clear insight as to the real nature of that force by i wh “?_, |)Cr iments IU ‘, 
repdled by the poles of a magnet. From an extensive senes of M ^ ^ 
with different bodies, and under the most diverse circumstance-, , e {o(tc a* 
a few which clearly exhibited the law according to which to* "S' tbe rep® 1 *- ' 
ments when the strength of the repelling magnet is increased. ^ then ^ r , 
of a diamagnetic body dependent on any coustant property of - | )U t it i= 
pulsion must be simply proportional to the strength of the y franc* • 
oy the concurrent testimony of experiments carried on in ^ focre*-*’^ 
England, that for a wide range of magnetic power, the repu .* u i n evi , * bl >' l ' 
he square ot the strength of the influencing magnet. This a(onS oD the K 
conclusion that the repulsion of a diamagnetic body depends, n « » diil nisf ,,, 
il» Pe f r K Ung T a but u P° a ,he joint action of the magnet ^ 1* 
piece of bismuth, for example in the presence of the magnet, u , , !L r j e s, and r , , 
15 wwlk5i[ 0f<a l c " crnc " t * ' vhich voiles as the magnetic strength' wl „t^ , 
°JZ h,C f the - sub4tttncc ia repelled. The next question to he dec ■ ^ ab|cS s r . 
state of excitement evoked by one pole, in a diamagnetic t**? \ » 
an opposite quality to repel it. To decide this, two cores of ^ toge ,lu ' r " r .>, 
that the two semi-cylindrical ends of the cores could be Pj acC ‘ C " ht portion^' 
to form a single cylinder of the same diameter as that of the st»ig« I 
