On the 4th we came to Dhamoni, ten miles. The only thing remarkable here is the magnificent fortress, which is built upon a small projection of the Vindhya range, looking down on each side into two enormously deep glens, through which the two branches of the Dasan river descend over the tableland into the plains of Bundelkhand. The rays of the sun seldom penetrate to the bottom of these glens, and things are, in consequence, grown there that could not be grown in parts more exposed.
Every inch of the level ground in the bed of the streams below seems to be cultivated with care. This fortress is said to have cost more than a million of money, and to have been only one of fifty-two great works, of which a former Raja of Bundelkhand, Birsingh Deo, laid the foundation in the same happy hour which had been pointed out to him by his astrologers. The works form an acute triangle, with the base towards the tableland, and the two sides hanging perpendicularly over the glens, while the apex points to the course of the streams as they again unite, and pass out through a deep chasm into the plains of Bundelkhand.
The fortress is now entirely deserted, and the town, which the garrison supported, is occupied by only a small police-guard, stationed here to see that robbers do not take up their abode among the ruins. There is no fear of this. All old deserted fortresses in India become filled by a dense stream of carbonic acid gas, which is found so inimical to animal life that those who attempt to occupy them become ill, and, sooner or later, almost all die of the consequences. This gas, being specifically much heavier than common air, descends into the bottom of such unoccupied fortresses, and remains stagnant like water in old reservoirs. The current of pure air continually passes over, without being able to carry off the mass of stagnant air below; and the only way to render such places habitable is to make large openings in the walls on all sides, from the top to the bottom, so that the foul air may be driven out by the current of pure atmospheric air, which will then be continually rushing in. When these fortresses are thickly peopled, the continual motion within tends, I think, to mix up this gas with the air above; while the numerous fires lighted within, by rarefying that below, tend to draw down a regular supply of the atmospheric air from above for the benefit of the inhabitants. When natives enter upon the