256 MAJOK A. E. OXLEY ON THE INFLUENCE OF MOLECULAE 



Naph thalene 



& = 79'95 + '036 57/>-0 -00000 180p 2 



TT= 10,100 atmospheres. 



Carbon tetra-chloride 



&= -23-0 + 0-0350JO-0-00000147P* 



TT = 11,900 atmospheres. 

 Ethylene di- bromide 



3- = 9'85 + 0'0252p-0'00000125p 2 



TT = 10,000 atmospheres. 

 Formic acid 



TT =N= 7980 atmospheres. 



Potassium 



$ = 59'5 + 0'0146 -0'0000007^ 2 



7T = 10,000 atmospheres. 



Phosphorus 



^ = 43-93 + 0-0275j9-0-00000050p 2 



TT = 27,500 atmospheres. 



Sulphur, rhombic-monoclinic* 



$ = 95-4 + 0-03725jo + 0-00000213p 3 



TT % 8700 atmospheres. 



Solid CO. 



$ = -5G'8 + 0-01999p-0-00000075?) 2 



TT = 13,300 atmospheres. 



These values, it is true, appear rather high when compared with those found from 

 other considerations, but due importance must be attached to the difficulties of 

 experimental work of this nature and to the fact that the experimental data have 

 been extrapolated over a considerable pressure interval (several thousands of 

 atmospheres). 



Comparing these results with those given on pp. 252 to 254 it is considered that a 

 mean value of the intrinsic stress in diamagnetic crystalline media, viz., 2 x 10 9 dynes 

 per square centimetre is representative of the true order of magnitude of the forcive 

 which binds the molecules in the space lattice of a crystalline medium. This implies 

 that the energy per unit volume of the diamagnetic crystalline medium, in virtue of 

 the crystalline grouping, is comparable with 2x 10 9 ergs. 



* This transition of sulphur from the rhombic to the monoclinic form is accompanied by thermal 



gajy 

 absorption. Since j-^ is positive the transition line for different pressures will be convex to the p-axis. 



