In a former paper (Proc. R.S.E., 1905) an investigation was given of the magnetic properties of the closest packed homogeneous cubic arrangement of molecular magnets, and it was found that the results were in good agreement with the observed properties of crystals of magnetite. It was also suggested that a parallel investigation of other cubic arrangements might lead to a discrimination of molecular arrangement, so far as the magnetic constituents are concerned, in actual crystals. To settle this point, if possible, the present investigation was undertaken.