40 



The Trigonometrical Survey of India. 



[No. 1, 



Height 







Denominator 



of 

 vulgar frac- 



above sea 

 level. 



Names of Stations. 



ft 









tion. 



412 



Toolsipoor, T. S. 



.0763 



13.1058 



478 



Anarkali, T. S. 







.0744 



13.4432 



7732 



Jagesar, H. S. 





.. ... 



.0463 



21.5983 



6994 



Birond, H. S. 







.0652 



15.3374 



10101 



Khankra, H. S. 







.0579 



17.2652 



8526 



Soonchalia, H. S. 







.0624 



16.0256 



6946 



Ghoongti, H. S. 







.0652 



15.3374 



7079 



Ranigarh, H. S. 





.. 



.0687 



14.5624 



5675 



Mabegarh, H. S. 







.0750 



13.3333 



7371 



Ghandial, H. S. 





•• ... 



.0698 



14.3266 



1254.1 



Kiderkanta, H. S. 





• ■ ... 



.0480 



20.8377 



9946 



Nagtiba, H. S. 





.. ... 



.0521 



19.1902 



2970 



Dhoiwala, H. S. 





•• t- . 



.0628 . 



15.9363 



7454 



Banog, H. S. 





rt •■■ 



.0612 



16.3479 



3161 



Amsot, H. S. 





.. ... 



.0565 



17.6897 



11997 



Ckur, H. S. 









.0530 



18.8857 



73. 



Conclusion deduced ft 



*om 



foreqoi 



nq table. — 



Now since 



Sin ^L incidence 



•- = 1 -f- m in the mean state of atmosphere and at 



Sin ^_ refraction 



the level of the sea, and also, since the quantity m varies with the den- 

 sity of the atmosphere, so that when the density of the air is only the 

 nth part of what it is at the level of the sea, the refractive power is 



m 

 there only 1 -\ , it might have been expected from these tabulated 



results that in the first instance,/ 1 a : : r 



height of station of observation. 



No such law, however, is to be found unless the numerous exceptional 



cases be excluded to make a rule. 



74. Wherefore it appears, that the law of variation in f due to 

 variation in the density of the atmosphere, consequent on variation 

 in height, is completely absorbed and lost sight of in the irregular 

 variations, arising from local causes and also from the unavoidable 

 imperfections of observation to points so ill-defined as the apices of 

 snowy mountains. 



75. Finally it is to be noticed that the foregoing method is 

 acknowledged to be imperfect and unsatisfactory, but compared with 

 the ordinary mode of finding /from reciprocal vertical observations, 



