The aim of the Exhibition is to do honour to one whose influence on science has been singularly profound ; partly by a display of relics, partly by indicating the scope of his work, but more particularly by tracing what may be considered as the development of his great achievement. The modern mathematical laboratory may look upon Xapier as its parent. An endeavour has been made to make the Exhibition and Handbook useful to the laboratory computer, the engineer, the astronomer, the statistician, and to all who are interested in calculation.

The Editor desires to express his grateful thanks to many helpers : to Professor Whittaker and Dr Knott for help both with the general scheme and also in the details ; to the writers of the articles ; and to the lenders of the
exhibits.