100 A. M. Mayer—Effects of Magnetization 
After the quantities given in the columns, I have written ¢ 
to designate the elongation of the rod, and r to indicate its 
retraction. 
u 
gives the elongations and retractions of Table I expressed in 
fractions of the inch of “ Troughton’s scale.”* 
Table III contains the coefficients calculated from the num- 
bers given in Table IL. 
rtain numbers of the tables are followed by * or by +; 
* indicates the maximum effect observed in the iron, or in the 
steel rods, corresponding to the phase of experiment given in 
the heading of the columns of Table I, or as subsequently 
break-circuit,” we see that rod No. 8 gives the maximum effect 
observed, while rod No. 1 gives the minimum 
The phenomena of Elongation and Retraction observed in Rods of 
Steel. 
. 
_ The phenomena observed in the magnetization and demagne- 
tization of the rods of steel have not been referred to. Here 
we have presented to us remarkable results. On first passing 
the current around rod 000, of soft steel, it elongated ‘8 of a 
scale-division, behaving like a rod of soft iron; but, on break- 
ing the cireuit, to my astonishment, it again elongated ‘6 of a 
division, thus rock this rod with a permanent elongation 
of 1-4 divisions; and this elongation exceeds the permanent 
* “Two copies of the new British Standard, viz, a bronze standard, No. 11, 
and a malleable iron standard, No. 57, have been presented by the British govern- 
Uni ies of careful compari 
:. I er - Bache,—of 
No. 11, with the Troughton scale of 82 inches, showed that the British bronzé 
sta m merican . So that in very 
exact measures with the costar, it is necessary to state whether the standard is 
ich deat? 
g . 
“Vo. Notes on Physics,” by A. M. Mayer, p.12. Van Nostrand, New York. 
