Tredgold on the Steam-Engine. 2 1 9 



ferent gradations, thus strictly aimed at, are gratuitous assump- 

 tions with which Nature has nothing to do; and which fre- 

 quently lead to the establishment of fake hypotheses. 

 [To be continued.] 



XXXVI. Notices respecting New Books. 



The Steam - Engine : comprising an Account of its Invention and Pro- 

 gressive Improvement, with an Investigation of its Principles and the 

 Proportions of its Parts for Efficiency and Strength ; detailing its 

 Application to Navigation, Mining, impelling Machinery, Sfc. with 

 20 Plates and numerous Wood-cuts. By Thomas Tredgold, 

 Civil Engineer, Member of the List, of Civ. En. fyc. Price 21. 2s. 

 4to. Jos. Taylor. 



A BRIEF analysis of the contents of this valuable work will give 

 our readers some idea of its utilitj', as well as of the immense 

 degree of labour necessary to collect, arrange, and reduce to their 

 elementary principles, the various phaenomena concerned in that 

 master-piece of human contrivance, the Steam-engine. In so doing, 

 we propose to follow, in some degree, the author's statement of its 

 contents in his Preface j with the addition of many particulars he 

 has not noticed in that short summary. 



The work is in sections. The first contains a short history of 

 the invention and improvement of the steam-engine, the inventors 

 being noticed in the order of "the dates of their first essays, com- 

 mencing with the Marquis of Worcester, and closing with Woolf 

 and Oliver Evans : a short sketch is added of the rapid progress of 

 the application of steam power ; and the section concludes with the 

 remark " that the whole tends to prove that the steam-engine, in 

 the highest state of perfection it has yet attained, is entirely of 

 British origin. The remark extends to the discovery of physical 

 principles, as well as of mechanical combinations. No new princi- 

 ple, nor no new combination of principles, has yet been derived from 

 a foreign source, the most perfect of foreign steam-engines being 

 professedly copied from British ones, and not unfrequently manu- 

 factured by British workmen." 



The second section treats of the nature and properties of steam, 

 its elastic force, expansive force, and motion ; first stating the ge- 

 neral principles of the equilibrium of heat, the phaenomena attend- 

 ing a change of state, and a comparison of the best experiments on 

 the quantity of heat required to convert bodies into vapour or steam, 

 with the necessary formula for the comparison. The elastic force 

 is next considered, with the principles which guided the author in 

 his choice of a formula for a case where empirical means are neces- 

 sarily employed: and here we remark for the first time a formula for 

 the expansion and expansive force of water, free from the objec- 

 tion of becoming negative in either high or low temperatures. The 

 connection between the boiling point of sea-water and the force of 

 its steam is treated, and a simple formula for the force of vapours 

 is shown to apply to those from various fluids, wtfh the necessary 



2F2 correction 



