Besides an immense volcanic cone, in part fallen in, and where the ground resounds under one's feet, each of the mounts has several lateral mouths and a number of fissures and chimneys, or passages, which bear evident traces of subterranean fires. They are entirely composed of trachytic rocks, scoria, lava, felspar, &c.
The Siamese have made temples of the largest of these caverns, which are of great depth and breadth, and extremely picturesque. One of the caverns of Samroum is quite inaccessible. Having descended to the depth of 20 feet by a chimney 2 feet wide at its mouth, and shut in between rocks, I found myself at the entrance of a deep cavern, but there all my efforts to proceed farther were defeated; a few steps from the entrance my torch suddenly went out, my breathing was checked, and I in vain fired my gun several times in order to disperse the foul air.
To you, my dear brother, I address my last letter before quitting Bangkok for my long journey to Laos. I have waited till the last moment for the steamer which ought to bring me letters from Europe, but unfortunately I am obliged to set out without receiving any answers to those which I sent in May, on my return from Cambodia. I fear that, once in the interior of the country, I shall have no means of sending letters; arm yourself, therefore, with patience, dear brother, and do not think me neglectful if you do not receive any; but be sure that I, alone in those profound solitudes, shall suffer more than you, from my ignorance of everything concerning those dear to me; and during the eighteen or twenty months which the journey will probably occupy I shall not see a European face nor hear a word which can recall to me my beloved country.
I have done everything in my power to obtain letters and passports from the French and Siamese authorities here, but all have been nearly useless. I have obtained nothing but a letter from the King's brother, who has the superintendence of the provinces north of Laos, and with that I trust to be able to get on. The good Dr. Campbell has supplied me with medicines of all kinds, and as I am nearly acclimatized, and have with me devoted followers--one particularly, Phrai, who would die for me--you may be easy on my account. Besides, and I really know not why, I have hitherto been much liked by the missionaries and natives, and I am sure it will be the same there. Fever does not kill all travellers. I have traversed many dangerous districts in my journey to Cambodia, and I am safe. Let us trust in God, my brother, that I shall be as fortunate in this expedition, and that we shall meet again. Nothing is requisite but courage, hope, and patience. I am sober, and drink nothing but tea. My food is the same as that of the natives, dried fish and rice, and sometimes a little game which I shoot, and roast on a spit after the fashion of the natives, that is, by two bamboos stuck into the ground and another laid horizontally on them, which is turned from time to time. My amusements are hunting, arranging my collections, my drawings, to which I devote a great deal of time, and of which some are not bad, as you may judge by those sent to the Geographical Society of London, and my journal; with those I pass many pleasant hours. Besides, you know how I love nature, and am only really happy in the woods with my gun, and that when there, if I know you all to be happy, I have nothing to wish for. I often think of our good old father, but as long as you are with him I feel easy about him; you will make him bear my absence patiently, repeat often to him how I love him, and how happy I shall be when I can tell him about my long journeys. And you, my brother, love and cherish your two dear children, my little nephews; inculcate in them the love of nature, and teach them to think that virtue is recompensed even here, and a good conscience ennobles more than patents of nobility, or orders in the button-hole; bring up your little ones in the love of God, and of all that is good and great. Think and talk sometimes with Jenny of the poor traveller. Adieu, my brother!