The present volume concludes the author’s ‘Lives of the Engineers.’ Its preparation was begun many years since. The favourable reception given to the ‘Life of George Stephenson,’ the principal improver and introducer of the locomotive engine, encouraged the author to follow it by a Life of James Watt, the principal inventor and introducer of the condensing engine. On making inquiries, however, he found that the subject had already been taken in hand by J. P. Muirhead, Esq., the literary executor of the late Mr. Watt, of Aston Hall, near Birmingham. As Mr. Muirhead was in all respects entitled to precedence, and was, moreover, in possession of the best sources of information, the author’s contemplated Life of Watt was abandoned, and he satisfied himself with embodying the substance of the materials he had collected in a review of Mr. Muirhead’s work, which appeared in the ‘Quarterly Review’ for July, 1858.

Having recently, however, through the kindness of M. P. W. Boulton, Esq., of Tew Park, Oxon, been enabled to examine the extensive collection of documents brought from Soho, including the original correspondence between Watt and Small, between Watt and Boulton, and between the latter and his numerous intimate friends and business correspondents, it has appeared to the author that, notwithstanding the valuable publications of Mr. Muirhead, the story of the life of Watt is one that will well bear to be told again, in connexion with the life and labours of Matthew Boulton of Soho. The two men were so intimately related during the most important period of their lives, and their biographies so closely intermingle, that it is almost impossible to separate them. They are therefore treated conjointly in the present volume, under the title of ‘Boulton and Watt,’ the name of the old Soho firm which so long enjoyed a world-wide reputation. But though the name of Boulton takes priority in the title, that of Watt will be found in many respects the most prominent in the narrative.

The MS. papers which have been consulted for the purposes of the present volume are of an unusually complete and varied character. They consist of several thousand documents selected from the tons of business books and correspondence which had accumulated at Soho. The most important were selected and arranged by the late M. Robinson Boulton, Esq., who entertained the highest regard for his father's memory; and, from the character of the collection, the author inclines to the opinion that it must have been made with a view to the preparation and publication of a Life of Matthew Boulton,—which has not, however, until now been undertaken. Thus, among sundry papers endorsed “M. Boulton—Biographical Memoirs,” is found a MS. memoir in the handwriting of James Watt, entitled “Memorandum concerning Mr. Boulton, commencing with my first acquaintance with him,” and another of a similar character, by Mr. James Keir,—both written shortly after Mr. Boulton’s death. Another collection, endorsed “Familiarum EpistolÆ et SelectÆ, 1755 to 1808,” contains letters received from various distinguished personages in the course of Mr. Boulton’s long and interesting career. The number of original documents is indeed so large, that, but for a rigid exclusion of non-essential matter, these Lives must have expanded into several volumes, instead of being compressed into one. But the author believes labour to be well bestowed in practising the art of condensation, and that the interest of biography gains much by judicious rejection. What Watt said to Murdock as to the production of a machine, holds equally true as to the production of a book,—“It is a great thing,” said Watt, “to know what to do without.”

Besides the memoirs of Boulton and Watt, which occupy the principal places in the following volume, it will also be found to contain memoirs of the other inventors who have at various times laboured at the invention and application of the steam-engine,—of the Marquis of Worcester, Dionysius Papin, Thomas Savery, and Thomas Newcomen. The author has also been enabled to gather from the Boulton papers a memoir of William Murdock, which probably contains all that is likely to be collected respecting that excellent and most ingenious mechanic.

In addition to the essential assistance received from M. P. W. Boulton, Esq., in preparing the present book, without which it would not have been undertaken, the author desires to record his acknowledgments to J. W. Gibson Watt, Esq., for information relative to James Watt;—to Charles Savery, Esq., Clifton, J. T. Savery, Esq., Modbury, Lieutenant-Colonel Yolland, R.E., and Quartermaster Connolly, R.E., for various facts as to the family history and professional career of Thomas Savery, inventor of the “Fire Engine;”—and to Thomas Pemberton, Esq., Heathfield; W. C. Aitkin, Esq., Coventry; George Williamson, Esq., Greenock; the late J. Murdock, Esq., Handsworth; and the late Mr. William Buckle, of the Royal Mint, formerly of Soho,—for various information as to the lives and labours of Boulton and Watt.

In his treatment of the subject, it will be observed that the author has endeavoured, as much as possible, to avoid introducing technical details relating to the steam-engine. Those who desire further information on such points, are referred to the works of Farey, Tredgold, Bourne, Scott Russell, Muirhead (‘Mechanical Inventions of James Watt’), and other technical treatises on the subject, where they will find detailed particulars of the various inventions which are only incidentally referred to in the following pages.

London, October, 1865.