54 GREAT TRIGONOMETRICAL SURVEY OF INDIA. 



on the boundary between Siam and Tenasserim. All the officers 

 suffered more or less in health after their exposure aud privation in 

 the Tenasserim jungles, and the want of a sanitarium in Burma to 

 enable men to recruit before entering the duties of a fresh season 

 was much felt. 



This series had now reached a point about 35 miles south of 

 Tavoy, from which the direct distance to Bangkok, the capital of 

 Siam, was only 90 miles, while the distance round the coasts 

 was fully 2,000 miles. As a check on the marine surveys it was 

 very desirable for a chain of triangles to be carried across into 

 Siamese territory, and to this the King of Siam readily assented. 

 Singularly enough, the tract of British territory lying up to the 

 Siamese boundary, though only 42 miles in width, proved the most 

 difficult piece of all, the hills (composed chiefly of metamorphic rocks) 

 being generally flat with no commanding points, while the dense 

 tropical vegetation and unusually long rainy season of 1878 were 

 further obstacles to speedy progress. Once across the frontier the 

 country suddenly became more favourable, and with the ready 

 co-operation of the Siamese officials good progress was made up to 

 within 25 miles of Bangkok, the remaining portion being continued 

 by Captain Hill late in the following year, and completed by 

 Mr. McCarthy at the beginning of the season 1880-81. 

 Mr. McCarthy also determined the position of the six next most 

 important towns in Siam ; one of the stations selected was part of 

 the celebrated Phra Pratom pagoda, the largest in Siam. The 

 outside circuit of its enclosure is 3,251 feet. Within this enclosure, 

 which is cloistered and turreted, are other cloisters, temples, and 

 belfries built on successive plateaux, while from the centre of the 

 highest a great bell-shaped spire springs to the height of 347 feet 

 above the ground. Besides these places the positions of several hill 

 peaks on both sides of the head of the Gulf of Siam were deter- 

 mined, compass sketches made of several of the chief rivers and 

 canals, and a plan of Bangkok prepared on the scale of four inches 

 to the mile. 



In November 1880 Mr. McCarthy was requested by the British 

 Vice-Consul, Mr. Newman, to accompany a Siamese telegraphic 

 expedition then about to start for the Natyadung pass, on the 

 British frontier, about 55 miles higher up than the Amya pass, by 

 which the survey party had crossed into Siam. The whole route up 

 to the former pass was measured with cane ropes, and Mr. McCarthy 



