PREFACE. xi 



The various modes of applying the power of steam are shown, with a classification 

 of engines ; and the velocity and proportions which give a maximum of effect in 

 engines, as well as the nature and office, and the power lost in working the air 

 pumps of engines, are investigated. 



The Fifth Section treats of the construction of the essentially different varieties 

 of noncondensing steam engines : these engines are all of the high pressure kind ; 

 and the causes of loss of power, and means of employing steam to the best ad- 

 vantage, and the mode of calculating the power and proportion of the parts, are 

 given in detail for each species. 



The Sixth Section treats, in like manner, of the construction, proportions, 

 power, and economy of condensing engines : in these sections, for the first time, 

 those minute causes which affect the action of steam are not only stated, but are 

 reduced to measure ; and I trust in such a manner as to be most useful, both to 

 those who wish to apply, and to those who wish to improve, the steam engine. 



In the Seventh Section the proportions and construction of the parts of steam 

 engines are considered, as of cocks, valves, slides, pistons, stuffing boxes, &c. ; 

 also the modes of opening and closing valves, and the like ; followed by a de- 

 scription of the different kinds of piston-rod guides, and an investigation of crank 

 motions, and of the combinations for producing parallel motion : also practical 

 rules for the strength of the various parts of steam engines are added, and 

 especially for boilers of different kinds. 



The Eighth Section treats, first, of the modes of equalizing the action of the 

 steam engine, as by fly wheels, or counter weights ; secondly, of regulating the 

 power of engines, as by valves, governors, regulators, &c. ; thirdly, the method of 

 ascertaining the state and intensity of the forces in engines, and the means of 

 measuring their effective power ; and, fourthly, of the mode of working a steam 

 engine. 



The Ninth Section illustrates the application of steam power to raising water, 

 to the drainage and business of mining, to impelling machinery for manufacturing 

 and for agricultural purposes, and its application to land carriage by means of 

 railways. 



The Tenth Section is on steam navigation ; and the stability of vessels, their 

 resistance to motion in fluids, the means of propelling them, and the modes of 



