on the Steam Engine. 323 



struction ; none is so likely to discover new methods of improvement. 

 Before we can control the powers of nature, we must learn their laws 

 or modes of action ; and our dominion over them can be commensu- 

 rate only with a knowledge of their properties. By studying the prop- 

 erties of flame, and especially of that which results from the combus- 

 tion of the mixed gases extricated in coal mines, Davy was led by a 

 short and easy route to the discovery of the safety lamp ; and it was 

 by learning the properties of the electric fluid, that Franklin subject- 

 ed to his control the lightning itself. 



Professor Renwick, we are happy to say, possesses in an eminent 

 degree the qualifications to which we have alluded. Well versed in 

 both mechanical and chemical philosophy, he is qualified to expound 

 the various scientific principles that are necessary to be understood, in 

 order to a complete knowledge of the construction of the Engine, or 

 of the nature of the dangers which attend it, while his situation at 

 the fountain-head of steam navigation, and his extensive intercourse 

 with manufacturers of steam engines, and the most successful build-' 

 ers of steam boats, afford him great facilities for becoming intimately 

 acquainted with the practical part of his subject. Under these fa- 

 vorable impressions of the author, we took up the work before us 

 v^ith the expectation of being highly gratified and instructed ; and 

 we are happy to add, that the perusal has not at all disappointed us. 

 We can therefore cordially recommend this Treatise, as a work which 

 contains an able and succinct account of the Steam Engine in its va- 

 rious forms, presenting a perspicuous view of this great subject in its 

 multiplied relations, as it regards its construction, the means of insur- 

 ing its safety, its applications, and its history. 



Under the head of "Mechanical and Physical Principles," with 

 which the work commences, we are presented with a concise but lu- 

 minous view of those principles of mechanics, and those laws of 

 heat, which relate to the Steam Engine. This part of the work is 

 well adapted to a numerous class of readers, embracing a large pro- 

 portion of the practical men for whom the Treatise was designed, 

 who. have not had an opportunity to acquire this knowledge in the 

 regular course of education ; and to many who had once acquired 

 the same information, it will serve as a useful review, and nothing 

 will contribute more to a clear and intelligent acquaintance with the 

 whole doctrine of the Steam Engine, and with all the discussions that 

 arise respecting the.sources of its dangers and their proper remedies, 

 than a fresh and familiar knowledge of these elementary principles. 



