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HISTORICAL SKETCH OF VAULTS.

observed, that the word “ vault” does not always implythe present mode of construction by voussoirs; andthough Pausanias speaks of the yErarium of Minyas,as composed of stones, the highest of which securedall the others, it does not follow that they were of awedge-like form: for a vault may be composed ofstones projecting one over another (more than halftheir size), so that the upper stone shall be necessaryto the stability of the whole.

The method of vaulting by voussoirs might beknown to the Romans, and to the Greeks, before thetime of the first Punic war; but it is more derogatoryto the latter people, in a contemplation of their build-ings, to suppose them acquainted with vaults so con-structed, than to suppose them ignorant of them. Inthe substitution of arches for lintels, the Romans inthe latter ages were able to cover spacious openingswith materials which, Sir Christopher Wren observes,a labourer might carry on his back.

From the circumstances that the domes of theRomans were built of brick and stuccoed, it has beenconcluded that they were ignorant of the art “ de lacoupe des pierres.” * The fact does not warrant theconclusion: their knowledge of the voussoir in thecommon cylindric arch shews their acquaintance withthe elements; and it is reasonable to believe, thateconomy and dispatch, rather than ignorance, deter-mined their practice. It was reserved for the timeand country of Perrault, in a display of skill, to sacri-fice economy and convenience in productions where

* See Phil, de Lorme Trai. d’Arch. 1567. Mat. Jousse Secretsd’Arcli. 1642. The Jesuit P. Derand, L’Arch. des Voutes. 1643.Le P. Dechalles, de lapidum Sectione, 1672. Frezier, coupe despierres et des bois, 1737-