Mentz is the usual place of embarkment for a voyage down the Rhine, the celebrated scenery of whose banks we determined to view, as some compensation for the loss of Switzerland. We were also glad to escape a repetition of the fatigues of travel by land, now that these were to be attended with the uncertainties occasioned by any unusual influx of travellers upon the roads. The business of supplying post-horses is here not the private undertaking of the innkeepers; so that the emulation and civility, which might be excited by their views of profit, are entirely wanting. The Prince de la Tour Taxis is the Hereditary Grand Post-master of the Empire, an office, which has raised his family from the station of private Counts, to a seat in the College of Princes. He has a monopoly of the profits arising from this concern, for which he is obliged to forward all the Imperial packets gratis. A settled number of horses and a post-master are kept at every stage; where the arms of the Prince, and some line entreating a blessing upon the post, distinguish the door of his office. The post-master determines, according to the number of travellers and the quantity of baggage, how many horses must be hired; three persons cannot be allowed to proceed with less than three horses, and he will generally endeavour to send out as many horses as there are persons. The price for each horse was established at one florin, or twenty pence per post, but, on account of the war, a florin and an half is now paid; half a florin is also due for the carriage; and the postillion is entitled to a trinkgeld, or drink-money, of another half florin; but, unless he is promised more than this at the beginning of the stage, he will proceed only at the regulated pace of four hours for each post, which may be reckoned at ten or twelve English miles. We soon learned the way of quickening him, and, in the Palatinate and the Brisgau, where the roads are good, could proceed nearly as fast as we wished, amounting to about five miles an hour.