ON THE MERIDIAN. .7 



Again ; the celestial arc between Pittchapolliam and Paughur was 

 observed to be 3 6 37.78, and the celestial arc between Punnae and 

 Pittchapolliam is 2 50 10.54, whose sum is. 5 56 48.32 for the whole 

 celestial arc. The terrestrial arc between Putchapolliam and Paughur was 

 21284.72 feet, to which add 1029100.5 feet, we have 2157572.5 feet, 

 equal 359595.4 fathoms, and. this compared with 5 5<5 48.32 gives 

 60469 fathoms nearly, for latitude 11 s 3 the middle point of the arc. 



As the two last arcs are nearly of the same length, and the results 

 differ but little, it has been thought sufficiently correct to take the mean 

 of the two decrees as the measure due to the mean latitude of the two 

 middle points, in which case we have 604663 fathoms for the length 

 of the degree in latitude 116 23.5. 



In" order to get a mean result between the observations made at 

 Dodagoontah and these two latter stations, the degree in latitude 10 34 

 49 has been taken and used with the degree in latitude 52 2 20 equal 

 60820 fathoms ; and with these the ratio of the earth's diameters has been 

 . computed, and found to be as 1 to 1.0030359 fart. 2 appendix); and 

 thence the length of the degree in latitude 116 23.5 has been found to be 

 60498 fathoms: therefore the mean between this and 60465.5 is 60486.75 

 fathoms : or, to avoid decimals, it has been called 6048.7 fathoms for lati- 

 tude 11 6 24. 



This mean measure has been used with the degree in latitude 52 2 

 20 and the ratio of the earth's diameters again computed, and the polar 

 and equatorial diameters are found to be as 1: 1.0031429, and I have 

 made use of this for determining the lengths of degrees in different lati- 

 tudes, by which the latitudes of all the great stations of observations in 



