This paper is a continuation of a paper communicated to the Society in July of last year, the publication of which was withheld until the whole subject could be treated as one. In the previous paper we discussed the magnetic induction in Iron and Steel Tubes. These tubes, and the nickel tubes now under discussion, were constructed primarily for the purpose of investigating their changes of volume under magnetisation ; but it seemed advisable to study as. many of their magnetic properties as possible.