PREFACE.

The Observations on Vaults, published aboutten years ago by the Royal Society of Anti-quaries, are now republished by the way of in-troduction to the subjects treated of in thesetracts ; and with the impression that the appli-cation of the principles of arches, to the varietiesof figure which vaults assume, deri ved from anytheory, would be much facilitated and extendedby an apt reference to their generic forms, andto the buildings where examples of each kindmay be found. The sections of ecclesiasticalbuildings are given in order to afford a test o fthe justness of such theory, with reference topractice.

The tables of bridges, which have been con-structed with considerable labour, the authorintended for publication at a future opportunity,in the hope of finding time to re-examine them,and correct any mistakes, in the data or cal-culations, which he may have made or have

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