364 SECTIONAL TRANSACTIONS. — <i. 



now in common use. Giving reasons for the greater success 

 of one generic type, he confesses his inability to name any 

 one machine which will do all sorts of work equally efficiently, 

 mentions the poor quality of knowledge often possessed by 

 those who actually operate tractors, but proceeds to encourage 

 designers and manufacturers to give us better and better 

 tractors, especially of better material, despite the temptation 

 to turn out less serviceable machines at low prices. Road- 

 haulage is a phase of tractor-work he asks designers to bear 

 in mind, but he admits that ' one machine for one job ' is a 

 principle that designers and users may have, for some years, 

 to respect. Tracing the history of the British industry, he 

 sympathises with tractor -manufacturers in the past, he holds 

 out hope of a fine future, if they will strive to give the 

 farmer the best machines, in design, material, and workman- 

 ship alike. He expresses his belief in the future of the 

 tractor industry. 



5. Mr. H. E. EicARDO. — A High-speed Internal-combustion 



Engine for Research. 



6. Prof. W. H. Watkinson. — A Dynamical Method of Rais- 



ing Gases to High Temperatures. 



7. Dr- C- Batho. — The Partition of the Load in Riveted 



Joints. 



Excursion. 



Ill the afternoon a visit took place to the Melingriffith Tinplate 

 Works. 



Thursday, August 26. 



8. Prof. J. T. Macgregor-Moebis. — A Portable, Direct- 



reading Anemometer for Measuring Ventilation in Coal- 

 mines. 



9. Mr. H. T. TiZARD and Mr. D. E. Pye.— Specific Heat 



and Dissociation in Intemal-com,bustion Engines. 



10. !^ir J- B. Henderson and Prof. H. E. Hass6. — The 



Indicator Diagram of a Gun. 



11. Prof. A. L. Mellanby and Mr. W. Kerr. — Steam Action 



in Simple Nozzles. A Short Study of the Variants in 

 Nozzle Expansion . 



This paper gives an exposition of a simple method of 

 dealing with the latter in ' straight ' nozzle expansion. It 

 is intended as an introduction to a more detailed considera- 

 tion, from the experimental point of view, of the same 

 ■problems. The general methods of investigating steam flow 

 are analysed, and it is shown that the somewhat neglected 

 search-tube experiments are the most promising. The 

 paucity of information regarding internal effects of steam 

 expansion is noticed, and it is contended that the ordinary 

 experiments on steam flow cannot give much further informa- 

 tion upon interior happenings. A series of equations are 

 derived from which the pressure ratio curve along a nozzle 

 can be calculated, and experimental evidence is brought 

 forward to show that the underlying theory is, at least, 



