52 OLDHAM: THE STRUCTURE OF THE HIMALAYAS, ETC. 



extent to which the attraction of the visible masses is neutralised 

 by a compensation whose centre of effect lies at these depths. 

 And finally in table No. 13 arc given the effect of the two modifica- 



Table 13.— Gravitation effect of two suppositions of departure from 

 a condition of support by simple flotation. 













Gravitation effect of Supposition. 





Distance from 









southern edge of 









supcrelevated tract. 



1 



11 





50 



+ -035 



+ -080 





40 



+ -035 



+ -07f> 





30 



+ -030 



+ -070 





20 



+ -025 



+ -060 





10 



+ -015 



+ 045 









+ -005 



+ -025 





10 



— -005 



+ -010 





20 



— -010 



— -005 





30 



— •015 



— -015 





40 



— -020 



— -020 





50 



— -020 



— -025 





60 



— -020 



— 025 





70 



— -015 



— 025 





80 



— -015 



— 025 





90 



— -010 



— -020 





100 



— -010 



- 015 





tions to the hypothesis of simple support by flotation which were 

 dealt with in table No. 10. Here again a reversal of the supposi- 

 tions and an assumption of over-compensation of the range, or part 

 of it, balanced by a corresponding under-compensation elsewhere, 

 would hardlv affect the numerical value of the correction but would 

 reverse its sign. In either case the values given in table No. 13 

 must be added, algebraically, to those given in table No. 11 for the 

 hypothesis of simple flotation. 



The tjangetic trough will be treated in a manner similar to that 

 adopted in the case of the range, and the effect calculated of an Ima- 

 ginary Trough, or rather series of troughs of different forms and 

 dimensions : but before this can bo done it is necessary to determine 

 what value will be adopted as representing the mean density of the 

 material with which they are tilled, and this can be determined 

 within narrow limits. The mean density of the superficial deposits 



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