Tetramorphism of Carbon, 159 



mate atoms of the square prismatic species into those of the coke 

 form, though the crystalline structure is not changed, and it must 

 therefore be considered as pseudomorphous. 



When pieces of coke are used for the electric light, that piece which 

 is attached to the anode is softened and partially converted into graph- 

 ite, whilst that at the cathode is unaltered. My attention was first 

 called to this fact by my friend Mr James Haywood. I found that the 

 specific gravity of a portion thus treated was 1*99 (correct for ashes), 

 which agrees with the supposition of its consisting of about ^ graphite. 

 Some parts were undoubtedly more perfectly converted into it than the 

 rest, and especially the points from which the electricity had passed, 

 but the appearance of the whole taken together, and its behaviour 

 when pounded, agreed very well with the above deduction. It would 

 therefore seem that this high temperature and positively electrical 

 state cause the atoms to lose their former polarity, and to take 

 others not having nearly so great an intensity of action, and thus ren- 

 dering graphite much softer than coke. 



Judging from these and other well-known facts, I am of opinion 

 that diamond has been formed at a comparatively low temperature, 

 the square prismatic species at about a low red heat, and coke at a 

 higher temperature. The fact of the portion of coke which is at- 

 tached to the anode being changed into graphite, and not that at the 

 cathode, indicates, I think, that the change is due, not so much to 

 the mere effect of heat, as to the combined action of heat and of a 

 highly positively electrical state. 



Although it may perhaps be too great a refinement, considering cir- 

 cumstances, I would remark that the fact of the specific gravity of 

 diamond being less than theory indicates, whilst those of coke and 

 graphite are greater, agrees with the above expressed view of it 

 having been formed at a lower, and them at a higher temperature 

 than the square prismatic species, with which they are compared in 

 the table. 



On the alleged evidence for a Physical Connection between Stars 

 forming Binary or Multiple Groups, deduced from the Doc- 

 trine of Chances. By James D. Forbes, F.R.S., Corr. 

 Member of the Institute of France, &c. Communicated 

 by the Author. 



An opinion has long obtained amongst astronomers that 

 the great number of cases which occur in the heavens of 

 two or more stars being apparently very close to one another 

 (constituting what have been called double, triple, or mul- 



