294 



LIEUT.-COLONEL S. G. BUERAED ON THE 



From the results of observations taken by Austrian observers at some of the coast 

 stations, Professor HELMERT had arrived at the conclusion that BASEVI'S values 

 required a correction of +0'047.* The importance of such a correction cannot be 

 overestimated ; it would have indeed the effect of largely neutralising the negative 

 character of the values of (.(/" y tl ) and of (H D) in Tables I. and II., and it would 

 render the value of (#o" yo) f r our standard station of Kalidnpur actually positive. 

 Such a correction would lower the line of sea-level as drawn on figs. 2 and 3 of 

 Plate 1 4, but would not otherwise affect the sections in these figures. 



Major LENOX CONYNGHAM' s first station in India was Dehra Dun; his results 

 there were astonishing, for they showed that BASEVI'S value was no less than 

 0'103 centim. too small. t LKNOX CONYNGHAM then visited Calcutta, Bombay, 

 Madras, and Mussooree. At Calcutta observations were rendered impossible by the 

 ceaseless vibrations of the ground, which proved sufficient to cause the pendulums, if 

 left suspended at rest, to oscillate visibly in a few minutes ; this effect on the 

 pendulums was produced in whatever plane the latter were swung. LENOX 

 CONYNGHAM had therefore to abandon Calcutta without obtaining any results ; that 

 lie failed where BASEVI had succeeded was probably 'due to the half-seconds 

 pendulums of the new apparatus being more affected by earth-vibrations than the old 

 seconds pendulums. 



* The correction for More was indeterminate, but probably larger than 0-047, owing to the lightness of 

 the stand employed. 



t This extraordinary difference could only mean that BASEVI'S final value of N was too small by 

 4 whole seconds of time. BASEVI'S observations at Dehra Dun lasted four months, and included 234 

 independent sets of swings taken at pressures varying from half-an-inch to 28 inches, and at temperatures 

 varying from 48 to 102" Fahrenheit. 



