OF BOWKS.

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servation of architects. The mode of domical vault-ing by pendentives, as practised at Saint Sophia, hasbeen called by Sir Christopher Wren , the Easternway of vaulting by hemispheres, and attributed tothe architects of the Eastern empire. It is ques-tioned, whether they are entitled to the honour ofgiving a name to this invention. There are the re-mains of a vault in an ancient bath at Catana inSicily , and in one of the halls of the baths of Cara-calla, so constructed. In Class VI. of the MuseumWorsleyanum, there are views of the interior and ex-terior of Saint Sophia; these and a plan will also befound in Grelot’s account of Constantinople .

The side (Fig. 7-) of a square inscribed in a circlewhose radius is 1, is 1.4142. The radius of the semi-circular supporting vault will be . 7071 , which, de-ducted from 1, the radius of the hemi-sphericalvault leaves .2929, the height of the part of the domenot crossed, *-^§. M. Grelot states the diameter ofSaint Sophia to be 18 toises, or 115 feet English , andthe versed sine at one-sixth of the diameter; fromthe foregoing it must be rather more than one-fifth.But when he says, “ II n’est pas permis a un chretiend’y monter, sil ne veut laisser son prepuce en bas •/*we must be grateful for the lengths and breadths hehas given.

It must be regretted that there are no satisfactoryaccounts of the twenty-five churches to Christ, ofthat to the holy Apostles , and to Saint John, atEphesus , of this age. It would have been a pleasureto have compared them with the fifty churches builtby Sir Christopher Wren, in London , and to havetraced the accumulated knowledge from a practice oftwelve centuries. The comparison might have con-