At one time he suggested going down the shaft of Brunel's tunnel at Rotherhithe, but the work was not far enough advanced to render it even commonly hazardous--that was abandoned. Going up in a balloon was suggested, but there was no utility blended with the risk. The dreadful dangers of Chelsea reach had already been encountered, and a colony established by his Lordship on the east end of Stephenson's Island, beyond Teddington--something even more daring must be tried; and, as it happened that a first cousin of my Lady Wenables had been reading to his Lordship, who was not able to read himself (from illness, not from want of learning), "Travels undertaken in order to discover the Source of the Nile," his Lordship at once resolved to signalise himself by undertaking a journey to discover, if possible, the "Source of the Thames." His Lordship was greatly excited to the undertaking upon being told that Mungo Park had been carried into Africa by a similar desire--and he observed with wonderful readiness, that if it were possible to remove a whole Park into Africa, there could be no insurmountable obstacle to transporting Lady Wenables to the source of the Thames. When Lord Wenables was first put upon the project, he was rather of opinion that the source of the Thames was at its mouth--"a part which," as his Lordship observed, "is in man the source of all pleasure;" and he suggested going by land to Gravesend, to look out for the desired object. But the Chaplain informed his Lordship that rivers began at the other end--upon which his Lordship, not having gone so far into the study of geography as to ascertain the exact course of the river beyond Stephenson's Island, hinted his intention of going with Lady Wenables by land as far as Dunstable, and then proceeding in the search. The Chaplain, it seems, although not quite sure enough of his experience to give Lord Wenables a downright negative to his suggestion, deemed it necessary forthwith to consult a map of Europe, in which the relative courses of the River Thames and the Dunstable turnpike-road are laid down in different degrees of latitude, and having ascertained that Dunstable was an inland town, proceeded to examine his charts until he discovered Oxford to be a more likely point to start from with any reasonable hopes of success; this he mentioned to Lord Wenables, and when his Lordship arose convalescent from his calipash fever, he mentioned his design to the Court of Aldermen on Midsummer Day, and the last week of July was ultimately and unanimously fixed upon for the expedition. "Instructions," says the author of the history of the expedition, "were, accordingly, agreed to be given to the Town Clerk, to secure such accommodation at an inn in Oxford, Reading, and Windsor, as might be adequate for the civic party; and to make every other necessary arrangement."