The principal mining districts are in Hainault, where those of Charleroi and Mons are not only the most productive, but exhibit the best specimens as to quality; those of Liege, which are next; and those of Huy and Namur. Some valuable coal mines at Limbourg have been ceded to Holland by the treaty of 1839, another cause of dissatisfaction to the Belgians. The prosperity of the mining trade has been affected by all the changing fortunes of the country; but its general march, though liable to great vicissitudes, has been in the ultimate result successful and improving. A few years since such was the rage for joint stock speculations, and the mania for erecting machinery in Belgium, that a panic was excited lest the veins of coal and iron should be exhausted prematurely, so rapid was the consumption of both which the force of speculation had produced. The price, in consequence, rose from 50 to 100 per cent, and an application was made and acceded to by the British Government, to permit the free exportation of coal from Newcastle to Flanders; but in the year following the alarm subsided, from very natural causes, and the price returned to its former level. The quantity produced in Belgium for some years past has not exceeded, on an average, three millions of tons; and the ordinary price has been about 10 francs at the pit’s mouth. The cost of carriage, however, and the variety of modes and distances of conveyance, render its prices at the various places of consumption extremely unequal. According to M. Briavionne,[10] the following was the scale in 1837:-- AT BRUSSELS: For large coals (droits d’octroi included), 42 francs for the ton of 1000 kilogrammes[11]. For manufacture (_gailletes_), 32 francs. AT GHENT: For domestic use 29f. 17c. For manufactures 22f. 6c. For slack 18f. 16c. AT ANTWERP: For large coals 36f. 55c. For manufacture 26f. 30c. For slack 22f. 30c. The price of coals in England, at the same period, was _twenty-two_ to _twenty-three_ shillings for what cost _thirty-five_ at Brussels; and from sixteen to twenty for the others, for which the Belgians paid from _twenty-five_ to _twenty-seven_. The cost at the pit’s mouth, at the same time, was but a shade higher at Newcastle than at Hainault or Liege,[12] so relatively imperfect are the means of communication in Belgium as contrasted with those of Great Britain; and, besides, the coal floors are much more accessible and thicker in the latter country than in the other, where the upper strata has been already pretty well exhausted by upwards of six hundred years of continued workings. We left Huy by the bridge, which here carries the road from the right to the left bank of the river; and continued its descent towards Liege.