Chemical Constitution of Bodies to Light. 295 



calcium : he thought it was due to the metals which were at 

 the base. 



Blackness is appropriate to extreme dissolution ; and, in 

 this connection, it was worthy of remark that many nations 

 had chosen that colour to express extreme grief. 



The conclusions of Prof. Horsford were, that the colour of 

 bodies depends upon the extent of the surface of their smaller 

 particles, or groups of atoms. Transparency depends upon 

 the arrangement of lesser atoms in certain order, constitut- 

 ing large groups. Whiteness depends upon such extent of 

 surface of the groups of atoms as shall reflect all light, or 

 upon such number of these plates produced by pulverizing 

 transparent bodies as will reflect all the light. Blackness 

 depends upon the subdivision of groups to such minuteness 

 that they no longer reflect light, or, by producing interference, 

 destroy it. Heat, by subdivision, causes darker shades. He 

 also observed, in a note, that there seem to be successive 

 scales of colours produced by heat. 



Professor Smith, of Louisiana, did not agree with Professor 

 Horsford in some of his conclusions, and shewed that there 

 were numerous exceptions in the mineral kingdom. There 

 has recently been discovered the amorphous or black diamond. 

 The diamond is generally supposed to be a clear, transparent 

 substance ; yet here was a specimen of a black variety, which 

 was proved by the investigations of Dufresnoy to contain 

 98 per cent, of carbon. The colour of this variety of diamond 

 proceeded entirely from molecular structure. — {Proceedings 

 of the American Association for the Advancement of 

 Science.) 



Notes on the Distribution of Animals available as Food 

 in the Arctic Regions. By Augustus Pbtermann. Esq., 

 F.R.G.S., &c. 



The occurrence of animals in the Arctic regions, and its 

 bearing on the missing expedition under Sir John Franklin, 

 is a subject which has of late excited a good deal of interest, 

 and has giving rise to the most conflicting and contradictory 



