ADVERTISEMENT. Vll 



The scientific and practical paper by Mr. Barlow, the ingenious 

 theoretical investigations of Mr. Mornay, together with the article con- 

 tained in this last paper, constitute a very extended, and, perhaps, 

 complete discussion of the interesting subject of paddle wheels. 



XL Practical rules for calculating the steam engine, illustrated by 

 numerous examples. To a person engaged in actual practice, even 

 though he be a first-rate mathematician, a rule and example put down 

 exactly in the order of work is much superior, in every respect, to 

 any mathematical formulae that can be set before him ; and this becomes 

 a matter of indispensable necessity and importance to such as are, 

 exclusively, practical men. It is hoped that these rules and examples, 

 and the copious index, prepared by Mr. Hann, a gentleman intimately 

 acquainted, both theoretically and practically, with the principles of 

 the steam engine, will add greatly to the utility of the edition now 

 offered to the public. 



In the explanation of the plates will be found a very lucid and 

 elaborate description, still further illustrated by the aid of numerous 

 wood-cuts in the text, of Stephensons' newest patented locomotive 

 engine ; and for this very able, complete, and popular account, we are 

 indebted to the liberality of Mr. Stephenson, engineer of the London 

 and Birmingham and other Railways : also, an account of Mr. Samuel 

 Hall's condenser, now much used in sea-bound vessels. 



To render the work of still greater utility, the Publisher has, after 

 much painful opposition, succeeded in producing examples of the 

 best sea and river vessels, practically illustrating the application of 

 steam-machinery to the purposes of navigation, in reference to the 

 principles of naval architecture ; and the Editor is indebted to Mr. 



