Much of the interesting and valuable information we have acquired of late years in reference to Siam, Cambodia, and Laos, we owe to the indefatigable labours of Henri Mouhot, the eminent French naturalist, who penetrated into regions previously unknown to Europeans in the years 1858, 1859, and 1860, and devoted himself to the service of Science with equal ability and zeal. He finally fell a victim to his heroic ardour--being seized with fever while on his way from Na-Lê to Luang Prabang, in Laos, on the 19th of October 1861, and dying, almost alone, with the exception of two faithful native servants, on the 10th of November. ~TEMPLE OF ONGCOR.~ He spent nearly four years in exploring the interior of Siam. As his biographer tells us, he first travelled through that country, then entered Cambodia, and afterwards made his way up the Mekong as far as the frontier of Laos. There he visited one of the wild and unconquered tribes which occupy the border-land between Cambodia and Laos and Cochin-China. Crossing the great lake Touli-Sap, he extended his researches into the remote provinces of Ongcor and Battambang, discovering some immense ruins of high antiquity, and more particularly those of the Temple of Ongcor the Great, which, with its terrace, portico, galleries, and peristyles, is perhaps a monument unparalleled in the world. The bas-reliefs with which it is adorned indicate considerable artistic skill on the part of those who designed and executed them. But what impresses the observer, not less than the beauty and grandeur of the various parts of the huge pile, is the size and number of the blocks of stone of which they are constructed. In a single temple as many as fifteen hundred and thirty-two columns! What means of transport, as Mouhot remarks, what a multitude of workmen, must such an enterprise have required, seeing that the mountain whence the stone was extracted is thirty miles distant! In each block may be seen holes an inch in diameter, and an inch and a fifth in depth, varying in number with the size of the blocks; but no traces of them are found in the columns and sculptured portions of the glorious structure. According to a Cambodian legend, these are the impressions of the fingers of a giant, who, after kneading an enormous quantity of clay, cut it into blocks and carved it, and then converted it into stone by pouring over it some wonderful liquid.