Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

viii PREFACE TO THE SEVENTEENTH EDITION. quirement the Author has rearranged, and incorporated under their proper heads, the several original and occasional materials; in- cluding Mr. Hurst’s valuable supplement. At the same time many useful Formulæ and Tables have been added, without divesting the Manual of its commodious size and form for pocket use. No pains have been spared to secure the utmost perfection. In correcting the proofs, not only have typographical errors been guarded against by the ordinary caution of comparison with the manuscript; but the correctness of the manuscript itself has been tested, by subjecting the proof-sheets to fresh and independent cal- culations, In short, neither has labour been stinted, nor counsel disregarded by the Author, in his endeavour to render the Seventeenth Edition worthy of the favourable reception ac- corded to its predecessors. , Guilford L. Molesworth. London, March, 1871.