44 General and Special Apophthegms, 



XXXV. The maximum difference, at a given period, be- 

 tween two or more languages is also capable of being 

 approximated. 



XXXVI. The original unity of the species is a postulate. 



XXXVII. The minimum amount of time necessary for the 

 maximum amount of difference is the measure of the shortest 

 admissible recent period, 



XXXVIII. The probable nature of the future changes in 

 the relationship between the diflFerent varieties of man is, 

 certainly, within the department of the ethnologist. In this 

 case, however, he reverses his method, and arguing from the 

 past and present to the future, argues from cause to effect 

 also. 



XXXIX. Still his proper sphere is limited to the appre- 

 ciation of physical influences. The historian measures the in- 

 fluence of a great warrior. The ethnologist inquires whether 

 the American of New England can be acclimatized to the 

 intertropical influences of Brazil. — Latham's Natural History 

 of Man, p. 559. 



On the Connection between the Colour and the Magnetic Pro- 

 perties of Bodies. By Richard Adie, Esq., Liverpool. 

 Communicated by the Author. 



In continuing my experiments* on the connection between the 

 colour of bodies and their magnetism, I was desirous, in the first 

 place, to determine the nature of several substances which contained 

 particles that moved on a sheet of paper to a magnet underneath ; 

 for, in applying this test, such bodies had appeared much more 

 numerous than I expected, and as I had been cautioned against the 

 prevalence of iron, which by treatment may become unmasked mag- 

 netically, I took care to prepare the salts free from this metal, 

 and to test for iron in every stage of the operations. Notwithstand- 

 ing these precautions, I found in the repetition of the experiments 

 metallic particles containing carbon to move on a sheet of paper to a 

 magnet underneath ; in every case such bodies forming only a small 

 proportion of the pulverulent mass, made me apprehensive that there 

 was yet some other impurity, rather than to suppose that this was the 

 true magnetism of those particles; an opinion that was soon con- 

 firmed. For, on substituting a sheet of silver foil for the paper, I found 



* See Vol. 50, p. 214, of this Journal. 



