292 LIEUT.-COLONEL S. G. BURRARD ON THE 



Northern India, such as Nos. 36 and 37, are situated in a deep wide 

 valley between two ranges of mountains, one of which, the Himalayan, is 

 visible, the other, with its summit at Station 24, invisible.* 



The northern end of the section in Hg. 3 conveys the idea that the Himalayan 

 mass is pressing upon the crust and producing a dimple, such as that described in 

 Chapter VII. of Professor GKOIWSK DARWIN'S work on 'Tides and Kindred 

 Phenomena.' 



The sections given in tigs. 2 and 3 of Plate 14 are based on Professor HKLMERT'S 

 condensation theory and have been constructed by means of his formulas from the 

 data in Table II. The numbers of the stations are not continuous, because pendulum 

 observations were not taken at all the astronomical stations. 



After 1874 no pendulum observations were taken in India, but the deflection of the 

 plumb-line continued to be determined in different parts of the country. By the 

 year 1900 the astronomical latitude of 159 stations, the astronomical azimuth at 209, 

 and the amplitude of 55 arcs of longitude had been observed, and thus a large amount 

 of evidence relating to the direction of gravity had accumulated. A discussion of the 

 datal; then available showed that it would be desirable to associate determinations of 

 the intensity of the force of gravity with observations of the plumb-line, and in 1902 

 the Indian Government sanctioned the re-opening of pendulum observations and the 

 purchase of a new apparatus of VON STERNECK'S pattern. 



(2.) Tin 1 Pendulnin Observations of 1003-04. 



The new apparatus was standardised at Kew and Greenwich in the autumn of 

 1903, and was taken to India by Major LENOX CONYNGHAM in November of that 

 year. Upon its arrival he thought it advisable to commence work at some of 

 BASEVI'S stations. The accuracy of BASEVI'S results, as given in Tables I. and II., 

 had been questioned by Professor HELMERT in his report to the International 

 Geodetic Conference of 1900. It had been there pointed out that the observer had 

 had no means of measuring the flexure of the pendulum stand, that during his 

 standardisation at Kew his pendulums had not been supported on the stand 

 subsequently used in India but between a stone pillar and a wall, and that when he 

 visited the high Himalayan station of More he had substituted a light portable stand 

 for that belonging to the Royal Society's apparatus. 



* Fig. 1 of Plate 14 shows that the altitude of Station 38 above sea-level is 145 metres greater than that 

 of Station 24; fig. 3 shows that if the underlying crust were brought to a uniform density of 2-8 the 

 altitude of Station 38 would be 1430 metres less than that of Station 24. The visible fall of nearly 

 500 feet from Station 38 to Station 24 is converted by the pendulum diagrams into a rise of nearly 

 4*700 feet. 



t 'Professional Papers of the Survey of India,' No. 5 of 1902. "The Attraction of the Himalaya 

 Mountains upon the Plumb-line in India," 



