18 Rev. O. Fisher on Dejflexions 
meridian deflexions which Major Burrard has calculated that 
the actual masses of the Himalayas would produce *. 
Thus the deflexion 83!"880 at the foot of the slope, when 
multiplied by cosine 45°, gives 59-313, while Major Burrard’s 
value at Dehra Dun, which is nearly in that position, is 
72", or 13" ‘more. 
In like manner the deflexion of 50390 at sixty miles 
from the foot of the slope, when multiplied by cosine 45°, 
gives 35-626, while Major Burrard’s value at Kaliana, which 
is somewhere near sixty miles from the slope, is 36". Lastly, 
the deflexion 18925 at Kalianpur, when multiplied by 
cosine 45°, gives 13'"°379, while Major Burrard’s calculated 
value is 18”. 
In each instance the hypothesis makes the meridian de- 
flexion rather too small; but it is obvious that, by taking 
the trend of the range more nearly east and west, the results 
would be brought to agree more closely. 
The residual result so far is that the hypothesis of exact 
isostacy causes the attraction of the visible masses to be 
almost exactly compensated except at places near the foot of 
the range. This is in accordance with Airy’s prediction f. 
But it is doubtful whether this hypothesis is sufficiently near 
the truth, because the ‘Transcontinental Gravity Measures, 
U.S.A.’, seemed to show that ‘* general continental elevations 
are compensated by a deficiency of density in the matter 
below sea-level, but that local topographical irregularities 
are not compensated for, but are maintained by the partial 
rigidity of the earth’s crust”. 
Following up the suggestion made by Mr. Putnam we 
notice how Mr. Oldham tells us that “ the very close resem- 
blance between the upper Sivalik beds and the recent deposits 
of the Gangetic Plain leaves little room for doubt that the 
Sivalik beds were deposited subaerially by streams and rivers.” 
‘The thickness attained by the Sivalik series is immense. 
Mr. Wynne estimated it at 14,000 feet in the North-west 
Punjab. In the Sivalik Hills there are at least 15,000 feet 
of beds and the. series is by no means complete, and similar 
vast thicknesses may be measured in any section.” In 
Mr. Oldham’s diagram (Man. Geol. India, p. 473) (fig. 1) he 
represents the Sivalik strata as lying beneath modern alluvium 
except at the northern edge where they have been disturbed and 
elevated into the sub-Himalayan Sivalik range. Following 
the above description, we may assume a layer of rock of some- 
* Report, tab. x. p. 94. 
7 Phil. Trans. vol exlv, p. 102; 
1 G. R. Putnam. Phil. Soc. Bulletin, Washington, U.S.A., vol. xiii. 
