286 Messrs. J. T. Bottomley and A. Tanakadate. [June 20, 



Finally, another bundle was built up, consisting of a much larger 

 number of fine annealed iron wires. With this the creeping was 

 almost insensible. 



It may be that the comparative absence of magnetic creeping, or 

 " nachwirkung," in these last experiments is to be ascribed to the 

 quickness with which the process of creeping completes itself in a finely 

 divided mass of iron : in other words, that the process is practically 

 complete in a time much shorter than the period of the magneto- 

 meter needle. The marked difference in effect between a solid core 

 (a single thick wire) of soft iron and a laminated core (a bundle of 

 fine wires) of the same material, suggests that in the former much 

 more than in the latter the process of creeping is retarded by the 

 eddy currents which are set up by those molecular movements in 

 which the process itself consists. 



[July 11th. — In seeking an explanation of the difference in beha- 

 viour it may be worth while to bear in mind that there is probably a 

 considerable difference in molecular structure between a solid core 

 and a laminated core of iron. If we accept the view that the mag- 

 netically neutral state is due to the molecular magnets forming closed 

 rings, these rings will for the most part be closed within the limits of 

 the separate constituent pieces of the laminated core, whereas in the 

 solid core they may be much larger, their dimensions being limited 

 only by those of the core itself.] 



I have received very valuable help in these experiments from two 

 students, Mr. David Low and Mr. William Frew, who have prosecuted 

 a troublesome research with much patience and zeal. 



III. " Note on the Thermo-electric Position of Platinoid." By 

 J. T. Bottomley, M.A., F.R.S., and A. Tanakadate, 

 Rigakusi. Received June 1#, 1889. 



In carrying out a series of experiments on radiation of heat by 

 solid bodies, an investigation to which one of the present writers has 

 for some time past devoted considerable attention, it became neces- 

 sary, for a purpose which need not here be detailed, to select a 

 thermo-electric pair of metals, of which one metal is essentially 

 platinum, as it passes through glass. Various pairs were considered, 

 and some trials were made ; and it was finally determined to make 

 use of platinum and platinoid. The latter metal is an alloy whose 

 electrical and mechanical properties were investigated some years 

 ago by one of the present writers;* and since that time it has 

 * J. T. Bottomley, ' Roy. Soc. Proe.,' 1885. 



