"The RHYN" or Rhin, is a little river, which, near its higher clearer sources, we were all once well acquainted with: considerable little moorland river, with several branches coming down from Ruppin Country, and certain lakes and plashes there, in a southwest direction, towards the Elbe valley, towards the Havel Stream; into which latter, through another plash or lake called GULPER SEE, and a few miles farther, into the Elbe itself, it conveys, after a course of say 50 English miles circuitously southwest, the black drainings of those dreary and intricate Peatbog-and-Sand countries. "LUCH," it appears, signifies LOCH (or Hole, Hollow); and "Rhyn-Luch" will mean, to Prussian ears, the Peatbog Quagmire drained by the RHYN.--New Ruppin, where this beautiful black Stream first becomes considerable, and of steadily black complexion, lies between 40 and 50 miles northwest of Berlin. Ten or twelve miles farther north is REINSBERG (properly RHYNSBERG), where Friedrich as Crown-Prince lived his happiest few years. The details of which were familiar to us long ago,--and no doubt dwell clear and soft, in their appropriate "pale moonlight," in Friedrich's memory on this occasion. Some time after his Accession, he gave the place to Prince Henri, who lived there till 1802. It is now fallen all dim; and there is nothing at New Ruppin but a remembrance. To the hither edge of this Rhyn-Luoh, from Berlin, I guess there may be five-and-twenty miles, in a northwest direction; from Potsdam, whence Friedrich starts to-day, about, the same distance north-by-west; "at Seelenhorst," where Fromme waits him, Friedrich has already had 30 miles of driving,--rate 10 miles an hour, as we chance to observe. Notable things, besides the Spade-husbandries he is intent on, solicit his remembrance in this region. Of Freisack and "Heavy-Peg" with her didactic batterings there, I suppose he, in those fixed times, knows nothing, probably has never heard: Freisack is on a branch of this same Rhyn, and he might see it, to left a mile or two, if he cared.