S64j Contributions to Physical Geography. 



lagers, who conceal their effects in them during the time of war. 

 Some of them are used as temples for their sacrifices. The 

 existence of others, their beauties and singularities, are secrets 

 which are never revealed, lest the Emperor or some great 

 mandarin should have the curiosity to visit them, for such 

 visits are always very expensive to the people among whom 

 they are made. A naturaHst would find in these caverns a 

 vast field for observation. They are all filled with petrifac- 

 tions and crystallizations which have various colours, and with 

 other remarkable singularities. 



One of the most remarkable of these caverns is a quarter of 

 a league long. It traverses a mountain from one end to the 

 other, and opens at both ends into fertile and well cultivated 

 plains. The whole of the bottom of the cavern is filled with 

 pure water from six to eight feet deep. It is easily navigated, 

 but for this purpose the traveller must be furnished with 

 torches. The roof appears to be formed of stones of the na- 

 ture of chalk. In some parts the roof is only from eight to 

 -ten feet above the water, while in others it rises to a very 

 great height. 



Near this cavern there is another, whose entrance is more 

 .surprising, and its interior elevation much higher. It con- 

 tains no water. Sometimes the roof is narrow, and sometimes 

 it widens, and forms immense chambers, containing natural 

 tables, altars, thrones, and moveables of every kind. These 

 wonders are all celebrated by the Tungkinese poets. 



In the same chain of mountains, and in the canton called 

 the Great Desert, about twenty leagues from the above cavern, 

 there is a cavern of immense size, and the largest in the coun- 

 try. It contains a fetid air, and its exhalations are insalubrious. 

 It can only be reached by sailing along a canal, the waters of 

 which cannot be drunk without danger. The canal itself 

 makes a number of turns, and at every turn it is necessary to 

 place a torch in order to find one's way out of it. Nobody has 

 yet ventured far into the cave. Its extremity has never been 

 reached, and it is unknown whether or not there is any other 

 entrance to it. — Expose Statistiqiie du Tunkin, sur la rela- 

 tion de M. De la Bissachese, p. 40-43. 



