368 ABSTRACTS OF SCIENTIFIC PAPERS 



phonograph allows the character of the sound to be determined 

 (' Nature,' vol. xvii. p. 423). 



XXXVII. Nest Gearing. ' Report of the British Association for 

 1883,' p. 387. 



Under this name Jenkin describes a number of forms of friction 

 gear of his invention, for the transmission of power by rolling con- 

 tact. The chief peculiarity of ' nest gears ' is that the rollers com- 

 posing them are so grouped that their mutual pressures are balanced, 

 to avoid producing thrust against the bearings. This invention was 

 the subject of several patents, and was employed in some of the 

 early forms of telpher locomotives, which _are illustrated in the 

 paper on ' Telpherage,' p. 262. 



XXXVIII. Gas and Caloric Engines, being one of the series of 

 Lectures on Heat and its Mechanical Applications delivered at 

 the Institution of Civil Engineers, February 21, 1884. 



The lecturer discusses the general theory of hot-air and explosive- 

 gas engines, and gives particulars of the results obtained by various 

 makers. The gas-engines of Otto and Clerk are described in some 

 detail, and experiments on efficiency and on the nature of the explo 

 sion are cited. The use of a regenerator is referred to, and the 

 original patent of Dr. Stirling is quoted in full in an appendix to 

 the lecture. Modern hot-air engines of the Stirling type are men- 

 tioned and their construction described by the aid of diagrams. 

 Attempts by Sir W. Siemens to apply the regenerator to internal- 

 combustion engines are alluded to ; and in this connection the author 

 gives a short account of an experimental engine constructed by 

 himself and Mr. A. C. Jameson, and of his own unsuccessful efforts 

 to introduce gas-engines of a novel type. The author concludes by 

 referring to the fact that Dowson gas allows the gas-engine even 

 now to compete on favourable terms, as regards economy of fuel, 

 with the steam-engine. ' Since this is the case now, and since theory 

 shows that it is possible to increase the efficiency of the actual 

 gas-engine two- or even three-fold, the conclusion seems irresistible 

 that gas-engines will ultimately supplant the steam-engine. The 

 steam-engine has been improved nearly as far as possible, but the 

 internal- combustion gas-engine can undoubtedly be greatly improved, 

 and must command a brilliant future.' The lecture is followed by a 

 number of appendices giving (1) a more extended account of the theory 

 of the subject : (2) examples of calculated theoretical indicator dia- 

 grams for air- and gas-engines of various types : (3) description of the 



