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



Europe can no longer be upheld ;* the so-called " marked negative variation" of many 

 writers has been found to rest on erroneous data. 



The theory of the compensation of the Himalayas has been based to a large extent 

 on the old pendulum results at Mussooree and More". The sections in figs. 2 and 3 

 show that a hidden deficiency of matter underlies the station of Mussooree (41) 

 equivalent to about three-fifths of the visible excess ; LENOX CONYNGHAM'S recent 

 result reduces this hidden deficiency to one-third only of the visible excess. 



Figs. 2 and 3 might lead to the belief that the Himalayas at More' (43) are almost 

 entirely compensated. The height of the visible excess is 4696 metres, the depth of 

 the ideal deficiency 4484 metres. But LENOX CONYNGHAM has not visited More, 

 and, as BASEVI employed there a special and lighter stand, it is impossible to gauge 

 the error introduced into his result by its flexure ; we have lately gained some idea of 

 the effects of the flexure of the lloyal Society's heavy stand, and we can only suppose 

 that the light More" stand was less rigid. That the Himalayas at More are 

 compensated to a considerable extent is certain ; that the error due to flexure could 

 have affected BASEVI'S result to the extent of 22 seconds of time is out of the 

 question. On the other hand, it is more than probable that the compensation, that 

 does exist, lacks that completeness, which has hitherto been considered among its 

 most remarkable features.! 



(3.) Deflections of the Plumb-line. 



In 1895 General WALKER published an admirable classification of the deflections of 

 the plumb-line that had been observed in India.j His object was to present the data 

 in the form of arcs of meridian and parallel for the use of mathematicians investigating 

 the values of the earth's axes. 



In 1898 Great Britain joined the International Geodetic Association, and Professor 

 GEORGE DARWIN, F.ll.S., was nominated to represent her at International Conferences. 

 These steps have brought India into touch with modern European ideas, and have 

 shown vis that the aims of geodesy are no longer limited to the measurements of arcs 

 of meridian and parallel, and to the determinations of the axes of a mean spheroid. 

 At the International Conference, held at Copenhagen in 1903, the following resolution 

 was passed : 



" II est desirable qu'on fasse dans les Indes anglaises une etude approfondie de la 

 repartition de la pesanteur, tant dans les contrees montagneuses que dans 

 les plaines. 



* No standard value of g has as yet been adopted by the International Geodetic Association. When 

 the absolute values of gravity at European standard stations have been finally determined, it may be found 

 that the values at Kew and Greenwich, which we are now accepting as o'ur standards, are not themselves 

 normal. Both BASEVI'S old and LENOX CONYNGHAM'S new values will then have to be corrected by a 

 constant quantity. 



t CLARKE'S ' Geodesy,' p. 350. 



| 'Phil. Trans.,' A, vol. 186, 1895. 



