the history of the London bills of mortality has been entered into at some length, as no place seemed more appropriate to that purpose than a reprint of the writings which first indicated the importance of the bills.
In preparing this book, the editor has received help from a number of persons, to all of whom he would express his appreciation of their kindnesses. It gives him especial pleasure to acknowledge the gracious permission of the Marquis of Lansdowne to consult the Petty papers at Bowood—though it became impossible for him to make use of that privilege—and to thank Lord Edmond Fitzmaurice for repeated suggestions. He has received valued assistance from J. Eliot Hodgkin, Esq., of Richmond-on-Thames, from the Rev. Dr William Cunningham of Trinity College, Cambridge, from Professor F. York Powell of Oxford, from Professor V. John of Innsbruck, from his colleagues H. Morse Stephens and Walter F. Willcox of Cornell, and from his sister. None of these however should be held responsible for such errors as may be found in the book.
Various officials of the British Museum, the Record Office, the Royal Society, the Bodleian Library, the libraries of Cambridge University and of Brasenose College, Oxford, of the Royal Irish Academy, the King's-Inns, and Trinity College, Dublin, of the Institute of France, the Universities of Leipzig and of Pennsylvania, and of Harvard and Cornell Universities have allowed the editor the use of sundry books and manuscripts. For privileges of this character he is under especial obligation to Professor Michael Foster, Secretary of the Royal Society, and to the Rev. Llewellyn J. M. Bebb, Librarian of Petty's college. He cannot omit to mention,
