Among the few circumstances which characterize the _Trade_ of Cashna, as distinguished from that of Bornou, the most remarkable is, that the Merchants of the _former_ kingdom are the sole carriers, to other nations, of a scarce and most valuable commodity, which is only to be obtained from the inhabitants of the _latter_. For though the salt of Bornou supplies the consumption of Cashna, and of the Negro Kingdoms to the South, yet its owners have abandoned to the commercial activity of the Merchants of Agadez, the whole of that profitable trade. The lakes, on the dreary shores of which this scarce article of African luxury is found, are separated from Agadez by a march of five and forty days, and are encompassed on all sides by the sands of the vast Desart of Bilma, where the ardent heat of a flaming sky is returned with double fierceness by the surface of the burning soil. A thousand camels, bred and maintained for the purpose, are said to compose the caravan which annually explores, in the savage wilderness, the long line of this adventurous journey. Perilous, however, and full of hardships as their labour is, the Merchants find an ample recompence in the profits of their commerce; for while the wretched villagers who inhabit the neighbourhood of the lakes, and collect the salt that congeals upon the shores, are contented to receive, or obliged to accept a scanty price, the value that the Merchants obtain in the various markets of Cashna, of Tombuctou, and of the countries to the South of the Niger, is suited to the high estimation in which the article is held. Attentive in this manner to the means of profiting by the produce of a neighbouring country, the people of Agadez are equally anxious to avail themselves of the commodities that are furnished by their own; for knowing the superior quality of the senna which grows upon their mountains, they demand and receive from the Merchants of Fezzan a proportionable price. The senna of Agadez is valued in Tripoli at fourteen or fifteen mahaboobs, or from 4l. 4s. to 4l. 10s. per hundred weight, while that of Tibesti is worth no more than from nine to ten mahaboobs, or from 2l. 14s. to 3l. sterling. From Tripoli the senna is exported to Turkey, Leghorn, and Marseilles. Of the other articles of sale which the extensive Empire of Cashna affords, the principal are— Gold Dust—the value of which appears to be estimated at a higher rate in Cashna than in Fezzan; for in the former the worth of an ounce of 640 grains (which is the weight of an ounce in Fezzan, Cashna, and probably in all the States between that kingdom and the Niger) is said to be nine mitkals, or 4l. 10s. sterling; whereas an ounce of the same weight is worth in Fezzan but 4l. In Cashna the value of an English ounce of 480 grains is consequently 3l. 7s. 6d. whereas in Fezzan it is only 3l.