40 MEASURE OF A DEGREE ON THE COROMANDEL COAST. 



t 



. From the remaining clear solution a magnesian pre* 



cipitate was produced by ammonia and phosphoric acid, 

 which, after driving off the ammonia by hes^t, weighed 0'18 

 of a grain. 



6. The solution had suffered too many alterations to allow 



me to separate, with any degree of accuracy, the muriate of 



soda ; but from a variety of* circumstances, I thought it no^ 



unlikely, that it would have been found pretty nearly in the 



same proportions, with respect to the other salts, as it exists 



in the Dead Sea. 



The Dead Sea The inference I drew from this was, th^t the River Jor*- 



Tam'Twater'' ^^^ ""^S^* possibly be the source of the salinp ingredients of 



concentrated the Dead Sea, or at least that the same spurce of impregna- 



by evaporation. ^^^^^ ^^^^^^^ ^^ common to both. This inquiry, however, 



would require a much more correct knowledge both of the 



proportions of the salts, and of local circumstances, than | 



have been able to obtain. 



VI. 



An Account of the Measurement of an Arc on the Meridian 

 of the Coast of Coromandel, and the Length of a Degree 

 ^ deduced therefrom in the Latitude of 12" 32', J5y Brigade 



Major William Lambton. 



(Concluded from Vol. XIX, p. 317.^ 



Reductions of JL HE reductions from thp hypothenuses to bring them tq 

 nusesf^^^ ^' ^^^ horizontal level were made by numbering the feet from 

 the old chain as they were measured, viz. by calling 32 

 chains 3200 feet, which would be 3200-115 feet by the new 

 chain; but this would produce no sensible errour in the 

 versed sign of a very small angle, and on that account these 

 decimals were not taken into the computation, which was 

 thought less necessary, since the whole deduction did not 

 amount to three inches. Neither was any notice taken of 

 the different heights of the hypothenuses or levels one abpve 

 another, as that differeiice was too trifling to affect a lengtl^ 

 pf thirty or forty chains. The base has therefore been con- 



9ideje4 



