368 ACCOUNT OF TIIIGONOMETRICAL 



MuUapvnnnbctta and Yai^acoyidah, the distance of 

 whose meiidians on a parallel of latitude pissing 

 throuirh Savendroog being nearly 135 miles. The 

 experiments were attcmpced, but the weather was so 

 dull that the lights could scarcely be distinguished. 

 There is bcsMes a difficulty in fixing the precise mo- 

 ment of extinction ; and even in the most favorable 

 state of the atmosphere, when the lights may be 

 distinctly seen with the naked eye at near seventy 

 miles distance, to come within half a second of the 

 truth, would be as near as the ej-e is capable of, 

 which is equal to 7'% in an angle at the pole : but 

 the mean of a great number of successful results 

 might come very near the truth. 



Since the triangles in this survey have been carried 

 direct from the observatory at Madraa to iMangalore, 

 by whicli easy means are offered to determine the 

 lengtli of a parallel of latitude subtended by two me- 

 ridians nearly five degrees and a half distant from 

 each other, it may be further suggested, whether a 

 long course of corresponding observations made at 

 Madras observatory and at another place on the 

 Malabar coast, by the eclipses of the satellites, oc- 

 cultations of stars by the moon, &c. might not aflpord 

 another eligible method for determining the length 

 of a deq-ree of lono-itude. 



In short, the difficulty of obtaining this desidera- 

 tum, and the important advantages to geography and 

 physical science which must accrue therefrom, are 

 such poweiful incitements to a zealous prosecution of 

 the inquiry, that I may venture an assurance of leav- 

 ing nothing undone, which may come within the 

 compass of my abilities, to give every possible satis- 

 faction on the subject ; and if my endeavours to 

 throw some light on the path to future discovery be 

 successful, I shall close the period of my labours 

 with the grateful reflection, that, while employed in 

 conducting a work of national utility, I shall have 

 added my humble mite to the stock of general 

 science. 



