Such feelings, Sir, have encouraged me to publish the following pages, which, as an earnest of their future success, I am permitted to dedicate to yourself.

A Work of this kind, combining in the most condensed form the acknowledged principles and recent improvements in Mechanical Science, and professing to be adapted in every possible way to the use of the Mechanic and Machinist, could not well find a Patron more congenial to its Spirit than one, who, during a long series of years, has laboured with no common devotion in promoting their benefit.

I am,

SIR,

Your most obedient, and

much obliged humble Servant,

JOHN NICHOLSON.

PREFACE.

THE discoveries of WATT and ARKWRIGHT, which yielded at once such immense national as well as individual prosperity, must ever be regarded as forming a new era in the arts of life and the domestic policy of nations. The riches, extraordinary as unprecedented, inexhaustible as unexpected, thus acquired by a skilful system of mechanical arrangement for the reduction of labour, gave the impetus which has led to the numerous discoveries, inventions, and improvements, in every department of our manufactures, and raised them to their present state of perfection.

With respect to our primary and most elaborate pieces of mechanism, however intricate and incomprehensible they may appear to the inexperienced, they are in the eye of the practical man mere elegant modifications and combinations of a few simple principles. These principles, after some necessary observations on the Forces acting on Matter, on Friction, and the Centre of Gravity, are fully elucidated in the account of "THE MECHANICAL POWERS."

These are followed by what is indispensably necessary to the proper construction of Mill-work, viz. a description of BEVEL and SPUR GEER, the longitudinal connextion of Shafts, termed COUPLING, the most approved

method of DISENGAGING AND RE-ENGAGING MACHINERY, and of the EQUALIZATION OF MOTION, with some general Practical Observations, given under the article "MILL GEERING."

The reader who attentively peruses these articles will be in possession of the primary points of MILL-WORK; we have, therefore, next introduced to his notice, under ANIMAL STRENGTH, WATER, WIND, and STEAM, the best modes of applying the MOVING POWERS; and to them is annexed a short, though concise, account of Brown's Vacuum or Pneumatic Engine, which may, with improvements, be made most effective for locomotion and other light purposes.

As the reduction of wheat into flour forms so essential a part of domestic economy, and as the force which gives a rotatory motion to the upper mill-stone is almost invariably imparted either by wind or water, we have thought it no deviation from scientific arrangement, to introduce at the end of these two articles a description of a FLOUR-MILL; as, by that means, the reader will be enabled to form a tolerably correct notion of the manner of imparting motion from the water-wheel, or leader, to the other parts of machinery. And while upon this subject we have, with a view to make the Work generally useful, described the hand and foot methods of grinding corn, that those who live not in the vicinity of a mill, or who do not choose to submit to the impositions said to be practised by many millers, may, at a comparatively trifling expense, have the work performed at home.

A knowledge of the STRENGTH of MATERIALS being

at all times important in the construction of Mill-work, more particularly in those parts which have to sustain the greatest force, or put the whole of the other parts of the machinery in motion, we have, next to the Moving Powers, inserted a letter from Mr. RENNIE, jun, to Dr. YOUNG, describing a series of very satisfactory experiments made on this subject.

A description of HYDRAULIC ENGINES next follows; and these are succeeded by certain SIMPLE MACHINES acting as accessories to our manufactures. So that, by the time the reader has advanced thus far, he will have become so thoroughly intimate with machinery, as easily to comprehend and appreciate the several excellencies of our STAPLE MANUFACTURES, which are next unfolded to his view.

The whole was intended to be concluded with an examination of those arts termed MANUAL, in a Treatise on the Art of BUILDING; except, indeed, with the addition of an Appendix, containing a short and concise treatise on PRACTICAL GEOMETRY and MENSURATION, with a Collection of approved RECEIPTS, and a GLOSSARY; but the interest which has lately been excited respecting RAILWAYS and LOCOMOTIVE ENGINES has led to the extension of the Work, about thirty pages, with an article on those constructions.

Although there are several very excellent treatises on Mechanics and Mill-work now extant, yet, presuming on an arrangement widely different to that of others, by which the least erudite and most inexperienced may acquire something more than a mere Superficial Knowledge of Machinery, the Author trusts that the following pages will meet with a favourable reception.

In the course of his labours he has derived material assistance from many of his scientific friends, to whom he thus publicly expresses his acknowledgments; and more particularly to that Gentleman to whom the volume is dedicated.

In a Work of such a nature it is generally understood that extracts are justified, as the description of many things not new are requisite, and the language could not in general be improved. In such cases, however, the authority has, in general, been acknowledged, and in a way calculated to advance the honour and interest of every improver and discoverer.

The volume in its design and execution is offered as a companion to THE WORKSHOP, consequently abstract and theoretical principles have been allowed to mingle no further than has been indispensably necessary to the perfect illustration of the use and application of the object described. The Work has, therefore, no similarity to the Mathematical Illustrations of WOOD, GreGORY, OF EMERSON, each of which, and more particularly that of Dr. OLINTHUS GREGORY, deserves to be spoken of with great respect.

A Book comprehensive and practical, embracing the whole subject as living and contemporaneous, and as connected with private profit and public glory, instructive to individuals and illustrative of the genius of the age in its best direction, has been the object of the Author, and he hopes he has not laboured in vain.

LONDON,

March, 1825.