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at Tios: the ductus litterarum does not appear to be moredirect in one instance than in the other. In the same chaptera correction of a similar kind is made by all the commentators,although improperly; where the proportions of eustylecolumns are said to be the same as the diastyle, instead ofthe systyle; which is the reading in the manuscripts.

In th e example which we shall take to illustrate the principlesgiven by Vitruvius for porticoes with the polytriglyph interval,it will be seen that the intercolumniation is to the diametervery nearly in the ratio of 2.71 to 1; and therefore the speciesof temple is diastyle, as the text states it to be.

The propyleum, or approach to the Athenian acropolis,is one of the few instances existing in which the Greeksincreased the interval between the central columns by thewidth of one metopa and one tri glyph more; and thus far itcorresponds with the hexastyle monotriglyph of Vitruvius.But it fails in the want of equality of the other intervals,which our author insists upon as necessary when the Doricorder is to be introduced divested of its defects. Henceif we compare the Doric hexastyle front of Vitruviuswith the Grecian example, we must imagine the angularintercolumniations of the latter to be the same as the others;the central interval remaining unaltered. The distance betweenthe axes of the central columns of the propyleum is 17-10.0;and between the axes of those next to them, 1 1.10.9; the extent,therefore, between the axes of the columns placed at the anglesof the front, upon the supposition of equality in all theintercolumniations exceptingthat in the centre, wouldbe65.5 6;and the diameter of the columns being five feet, the whole