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density of steam hitherto received, and I hope to publish before long more reliable data, derived from direct experiment, which will modify generally accepted opinions in this branch of science, and affect some deductions from them on which dependence has previously been placed.

In a second volume of Useful Information, which is in preparation, and intended for publication before long, I hope to give some original researches, with a new series of Lectures like those in the present volume. At present there need only be added that this Volume has been revised throughout, the plates engraved anew, and an index added for the convenience of reference.

W. F.

MANCHESTER: January 1860.





THE EARLY DEMAND for a Second Edition of this volume is to me a gratifying proof of a desire on the part of the members of the Engineering profession to benefit by the experiences of successful practice. The Lectures were intended for Working Engineers; and in order to secure for the volume as wide a circulation as possible, it is now published at a price which will bring it within the reach of the humblest practitioner in the constructive arts.

The order of the Lectures has been changed to facilitate reference, and ensure greater continuity of purpose; and at the end of the volume I have placed a short notice of the results of the experiments which I have recently conducted, at the request of the Royal Society and the British Association for the Advancement of Science, on the resistance of cylindrical vessels to compression from an external and surrounding force. These experiments will be found to furnish data, which will undoubtedly modify generally received opinions as to the strength of boiler flues and other similarly situated cylindrical tubes.

W. F. MANCHESTER: December 1, 1856.




IN PRESUMING to offer useful information to the members of an important profession, I would especially guard myself against an undue assumption of personal merit, and rather rest the justification of the title given to the present Volume upon the well-grounded public opinion, that the elementary principles of science are too much neglected in the study and practice of engineering.

It is generally admitted that one of the most popular and useful forms of imparting knowledge to others is that of public and entertaining Lectures, and I may therefore state that the Lectures, which I have now the opportunity of publishing, were mostly prepared at the request of the Directors of the various educational institutions of the North of England, and delivered to the mixed assemblies of their Members. The circumstances of passing events gave to some of the addresses considerable local and temporary interest; but it does not by any means follow, that thus hastily conceived, the subjects of which they treated were wanting in permanent value and importance to the mechanical student. On the contrary, the preparation of what I had to say, constantly opened out new fields of inquiry, and laid bare more openly the deficiencies in the education and therefore in the existing intelligence-of a numerous and important class of society. My object was to impart to working engineers, in intelligible and simple terms, all I myself knew of the varied branches of practical science which their calling embraces, and hence my

main reliance was on the results of my own practice and experience. But beyond this I had necessarily much to study in the labours of others, and my acknowledgments are therefore due to those authors whose writings have been quoted in confirmation of my own views. To the writings of Robinson, Arago, Dalton, and Pambour, I am especially indebted for certain confirmatory remarks and experiments on the nature and properties of steam and other elastic fluids. There is much yet to learn in this department of scientific research. Mr. Joule's new theory of heat, and the experimental inquiries of Regnault on saturated steam, are likely to produce important changes and greatly extended improvements in the theory and construction of the steam-engine, as well as in the mechanical application of other elastic fluids. Deeply impressed with the importance of the subject and the great difficulties surrounding it, I was induced to undertake the task from the consideration, that although I am not perhaps the most competent person to elucidate many of the subjects treated of in these Lectures, yet, in the absence of higher authorities, I felt I might render some service to the practical man, by placing within his reach some of the most remarkable laws of heat connected with the theory and application of steam as a mechanical agent. In thus acknowledging my own deficiencies, I shall consider my labour to be fully remunerated if I succeed in gaining the attention of those who are deprived, by their avocations and the limited time at their disposal, of the ordinary means of instruction.

In confirmation of many of the opinions advanced in the Lectures, I have deemed it necessary to give the experiments on the strength of sheet-iron plates and their riveted joints in full; as well as the direct experiments on the strength of boilers, on the pressure of steam at different temperatures, and on the causes of boiler explosions.

To constructive science I have given special attention, and I venture to hope that the experiments and recommendations relating to the best form and construction of boilers and other vessels subjected to severe strain will be carefully considered by practical boiler-makers and engineers,

and thus lead to greater security of life and property. In treating of the economy of fuel and the prevention of smoke, I have endeavoured to show that economy in the consumption of coal fuel is attainable without smoke; and I have converted the paper read before the British Association for the Advancement of Science into the form of Lectures, in order to render the subject easier of acquirement to those who are desirous of abating a serious nuisance, and of establishing a better and more economical system of combustion.

It would appear almost superfluous to insist upon the value of a sound knowledge of practical science;

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