TRIGONOMETRICAL SURVEY OF INDIA. 



197 



angle being a function of the compression, a knowledge of the figure of 

 the earth becomes here also an indispensable condition. 



Enough has perhaps already been said to warrant the conclusion 

 that this is one of the most important problems of astronomy in respect 

 to practical utility, and he who would deny the expediency of prosecut- 

 ing the researches necessary to its investigation, must be prepared to 

 pronounce the same sentence of exclusion against astronomy as con- 

 nected with navigation, against geography, against every other branch 

 of science, or else to waive all claim to consistency. But the figure of 

 the earth can only be known by a comparison of measures made in 

 parts of the globe separated from each other by a considerable difference 

 of latitude, such as two large arcs of the meridian or of longitude. 



Hence then we arrive at the absolute necessity, as far as science is 

 concerned, of establishing the exact relative value of the units which have 

 been used as standards by the various nations who have engaged in what 

 are called Geodetical operations, and first it is of all things requisite that 

 we should begin by having some decided measure of our own. 



For this purpose the Parliament of England selected the yard used by 

 Mr. Bird as the standard, and Captain Kater had the task assigned to 

 him of comparing all the other measures, such as Sir Geo. Shuckburgh's, 

 General Roy's, &c. with this ; a detail of the experiments made for this 

 purpose will be found in the Philosophical Transactions for 1821, as also 

 the comparison of the English and French standard measures with each 

 other. 



The French at the time of the Uevohilion of 17!>1, whi n the rage for 

 fraternizing and levelling was at its height, sought fur bouic means of 



c 3 



