Be these surmises and explanations founded or not, our journalist’s representation of the extent of the Oasis of Siwah, is not only at variance with every other account, but with the internal evidence to be extracted from his own account, and must be rejected as erroneous. Page 23, of the Journal, to which this note refers, a further subject of inquiry and explanation occurs, where Mr. Horneman, describing the ruins of an ancient edifice in the vicinity of Siwah, gives us dimensions and proportions, in every respect differing from those before stated by Mr. Brown, in description of the same building. The length in feet. The width. The height. By Mr. Brown, 32 15 18 By Mr. Horneman, 30 to 36 24 27 Mr. Horneman informs us, that he was successively interrupted on entrance into the area of these ruins, and was altogether prevented by the jealousy of the natives, from pursuing any plan of accurate examination or admeasurement. The dimensions which he gives us, are therefore to be taken as the result of computation on mere view; and from these and other circumstances, it is further to be presumed, that such computation by view, was made _from without_; whilst Mr. Brown expressly tells us, that he took his measurements _in the clear_, or _inside_ of the building. In this case, a deduction equal to the thickness of the walls, is to be made from the length and the breadth of the building, as described by Mr. Horneman. The thickness of the _end_ walls may be supposed to be much less than that of the _side_ walls, which being constructed to support the vast and ponderous blocks of stone which formed the roof, must have been built with a proportionate strength and solidity, not necessary, and probably therefore not used, at the entrance or end of the building. Mr. Horneman, indeed, when stating the thickness of the walls to be _six feet_, makes no such discrimination; but it may be fairly presumed, that adverting particularly (as he does,) to the massive roof, he meant to note exclusively, the strength of that part of the fabric by which it was supported. Under such probable conjecture, the length and breadth of the building given by Mr. Brown _from the inside_, and by Mr. Horneman _from the outside_, may so far agree, as fully to exculpate our Journalist from any charge of inattention in his survey, or inaccuracy in his representations; making those allowances which his situation and circumstances, and (above all,) his own declarations of want of precision, fully intitle him to. The comparative height of the building is a part of the subject, which suggests matter of new and interesting investigation.