52 
MR. S. W. J. SMITH ON THE THERMOMAGNETIC ANALYSIS OF 
wires were used for the primary and secondary coils, but a coil with a greater 
number of turns was substituted for the original heating coil. 
Except for occasional assistance, nearly all the permeability observations after the 
second winding were made by Mr. Satterly. 
§7. Meteoric Iron (2nd Winding ).—See fig. 10, &c. 
An attempt has been made, in the series of figures numbered 10 to 16, to represent 
the relations between the data obtained after the second winding. It required more 
consideration than might appear necessary at first sight to decide upon the form of 
some of the curves, and they may not be altogether free from such errors of inter¬ 
pretation as are difficult to avoid in the attempt to construct continuous curves from 
a set of discontinuous observations. 
Fig. 10. Meteoric iron (2nd winding). 
Field intensity = 0-43, C.G.S. values of /x = ordinates x 160-5 (approximate). 
Variation of permeability with temperature during continuous cooling from about 850 C., and continuous 
reheating to same temperature. 
Fig. 10 is intended to represent the variation with change of temperature 
of the permeability of the meteorite as it is cooled continuously from above the 
critical temperature to the temperature of the air, and then heated uninterruptedly 
until its ferromagnetism again becomes too small to he measurable. The numbers 
of the experiments upon which the curve is based are given in the figure. It will he 
seen that the greatest amount of uncertainty as to the form of the curve is in the part 
representing the cooling from 400' C. to 15' C. The similarity between 28 and 29 
(1st winding), and between 58 and 59 (2nd winding) seemed to suggest that the 
