of the Plumb-line in India. 21 
trappean area, it will produce a deflexion of 3-006 away from 
the range. 
Combining these results with those previously obtained, 
the deflexion at the foot of the slope of 18-759 is now raised 
to 23-768. At 60 miles from the range, the deflexion of 
3-212 towards it will be reduced to 1/857 towards it. At 
the edge of the plain the deflexion, which was 0'"682 towards 
the range, will now be 2!"324 away from it; and at greater 
distances will still be away from the range in a decreasing 
ratio. 
Thus the hypothesis of general isostacy of the Himalayan 
area and Gang etic plain combined, gives a considerable 
deflexion northward at the foot of the range; at some distance 
beyond 60 miles the deflexion disappears, while further 
towirds the edge of the plain—towards Kalianpur—the de- 
flexion becomes southerly, and so continues till it disappears. 
The extreme difference of the deflexions at the northern 
and southern edges of the plain will thus be about 26”, and 
in the meridian 20". In the table following p. 14 of the Report 
it is, in the meridian of Kalianpur, about "BO", as observed *. 
It is obvious that the dense rock of the Deccan wiil tend 
to intensify the southerly deflexion on the southern edge of 
the plain, and that, in general, irregularities in the geological 
structure of the country buried beneath the post-eocene 
deposits will be responded to by irregularities in the deflexion 
of the plumb-line. That this must occur appears from the 
table, where, in the column of deflexions, there are irregu- 
larities over the plain which seem inexplicable in any other 
way. 
Nevertheless, on the whole the trend of the deflexions from 
* The following is taken from the above table. N signifying a 
northerii and Sa southern deflexion as referred to Kalianpur. 
| | | 


| N. lat. Deflexion. N. lat. Deflexion. 
‘Th 2 ne pre ae MES bs gd ) 
oi i ‘ ia 
(een | 3048 | 33°04.N | Woh cosccseeccconu 2751 | O26N | 
| Mussooree ...... | 3027 | 36°84.N || Agra............... 27 10), | Sen | 
| Rajpoor ......... | e024" | 47-6a N || Ubira ”’..7......... 26 57 6°03 N 
paaaaot '. 2.05088. | 3022 | 29:15 N || Kesri ............| 25 46 5458 | 
| Dehra Dun ...... 3019 | 37°82 N || Pahargarh ...... 2456 | O-76N 
| E. end ditto, be 3017 3037 N ) Daiadhari ...... 24 38 1018S | 
2 ee aE 29 53 | 13°95 N || Surantal .. ...... 24 14 0°82 S 
|Kaliana ......... | 2631 | 7-:03N || Sironj ... .....: 24 9 1698 
Pintaisw , .sc85s | 28 44 6:13 N || Bhaorass ......... | 24 8 1:17 S 
ee | 28 31 567 N || Kalianpur ....... 24 7 | 0-0. 
Chanilaos......... 25 | L16N | 
