It has been found that in Co-31. 0% Fe-9. 0% Cr alloy the alpha //D has such small value as minus 0. 42 multiplied by 10** minus **5. The (d lambda /dH)//m is 0. 36 multiplied by 10** minus **6/Oe and is comparable with the absolute value of minus 0. 39 multiplied by 10** minus **6/Oe in nickel. The alpha //D for CO-37. 8%Fe-4. 3%Cr-16. 7%Ni alloy also shows a very small value of minus 0. 07 multiplied by 10** minus **5, while its (d lambda /dH)//m shows a very large value of 0. 80 multiplied by 10** minus **6/Oe which is about two times greater than the absolute value of nickel and five times greater than that of Ni-Span C.