[ 745 ] 
XXIX. On the Deflection of the Phmi-lim in India, caused hj the Attraction of the 
Himmalatja Mountains and of the elemted regions iegond ; and its modification hj 
the compensating effect of a Deficieney of Matter helow the Mountain Mass. By the 
Venerable JoH», He.w PK.m, M.A., Archdeacon of Calcutta. Communicated by 
Professor Stokes, Sec. B.S. 
Eeceived October 25,— Bead November 25, 1858. 
CONTENTS. 
§ 1. Eeference to a former Paper on this subject 
§ 2. Hypothesis of Deficiency of Matter below the Mountains, adopted in tiiis Paper 
§ 3. Summai,'of data and of some of the residls of the former Paper, oeeessa.,- for the presa,t"e'ikdiuM 
§ i. Coalculation of the efiect of Deficiency of Matter, according to the assumed hypothesis 
§ 5. Discussion of the Deflections under various circumstances, and of the effect upon the Ellipticitv 
of the Indian Are 
§ 6. General conclusions regarding the defect or excess of density in any part of the mass of the earth 
§ ”■ j^^^Exnix, containing a revise of some parts of the former Paper 
Page 
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748 
751 
759 
763 
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1 Eeference to a former Paiier on this subject. 
1. Two notices* which appeared last year in the Journal of the Astronomical Society 
on my Paper on Himmalayan Attraction, written at the Cape of Good Hope in 1854, 
and published by the Royal Society the year following, have called my attention again 
to this subject. Those who read that paper will remember, that it consisted of two 
parts ; the first a calculation of the amount of deflection of the plumb-line, caused by 
the Mountain Mass in India, at the principal stations of the northern part of the Great 
Indian Arc; and the second, the effect which the application of these deflections, as 
corrections to the astronomical amplitudes, would have upon the calculated ellipticity of 
the Indian Arc. I he results I arrived at are much greater than were anticipated. The 
author of the communications to the Astronomical Society proposes to test the truth of 
India^' Jexnaxt, Bengal Engineers, and First Assistant in the Great Trigonometrical Survey of 
I am indebted to Mr. Texxaxt for having detected a numerical error in page 98 of my paper. By ^oing 
through the calcidations, in page 98, it wiU be seen that 
for a=-0-0039737-0-0051426w+0-001688H, 
we must read «= -0 0019203 + 0 0059576M-0-0014564ti. 
This Will change the value of «(1 + a) in the next line but one. These corrections have no effect, however 
upon the results of my paper. When the paper was written, I was far away from all means of employing 
a computer, as is usual in such cases, to verify the long numerical calculations, not one-tenth of which 
appears 111 what is printed. In the last section of the present communication I have given a revise of such 
parts of the former one as need correction. 
MDCCCLIX. 
5 F 
