[2] Pronunciation near English "tie." GEOGRAPHY Whatever more or less final rectifications of frontiers result from the current war, the land of the Thai will still, for general purposes, fall into four geographic divisions of major importance: Northern, Central, Eastern, and Peninsular. Northern Thailand, lying between the Salwin and the Me Khong, two of the world's most majestic rivers, is, for the most part, a country of roughly parallel ranges and valleys running north and south. At the heads of the flat-floored valleys, which vary in elevations above sea level from 800 feet in the southeast to 1,200 feet in the northwest, arise important streams, the Me Nan, the Me Yom, the Me Wang, and the Me Ping, which, falling through narrow defiles to debouch in the low land of Central Siam, eventually there conflow to form the Me Nam Chao Phraya, the chief artery of that division. On the alluvia of these streams, as might be expected in a country whose civilization was originally based upon riziculture, live the great bulk of the northern Thai or Lao, in a setting of rich fields and orchards. The ranges similarly rise, southeast to northwest, from low, rounded hills to imposing peaks, many of which exceed an altitude of 5,000 feet and two of which achieve more than 8,000 feet. These mountains, rising abruptly from the valley floors and, on the whole, densely forested, are scarcely inhabited by man except for scattered groups of seminomadic hill tribes, which exist there by hunting and a primitive agriculture. The northernmost province, Chiengrai, is separated from the sister provinces by a mountain wall and belongs wholly to the Me Khong drainage; it is largely a region of marshes and grassy savannas. Central Siam, the heart of Thailand, is the vast alluvial plain of the Chao Phraya and may be described as 55,000 square miles of almost unbrokenly monotonous scenery. The level of the land is but little higher than that of the sea and, during the dry season, tidal influence is plainly evident as much as 50 miles from the river's mouth. Alluvial deposits, brought in the season of floods from the northern hills, are, however, raising this level at an astonishing rate; geological evidence shows that within comparatively recent times a great part of the plain was covered by the sea and even now the northern shores of the Gulf of Siam, at the mouth of the Chao Phraya, are advancing seaward at a rate of almost a foot a year. Its rich soil, its abundance of watercourses, both natural and artificial, and its comparatively dense population combine to make it one of the most eminently suitable areas of the world for the production of fine rice.