September 29, 1923] 



NATURE 



475 



advance came to steam locomotives by the use of 

 superheated steam. This was no new thing, for Papin 

 in 1705 seemed to have an appreciation of its v^alue. 

 As pressures and the resultant temperatures increased 

 there came difficulties with lubrication. With the 

 increased use and knowledge of mineral lubricants 

 Dr. Schmit was in 1895 able to devise methods of 

 using superheated steam which have been of the greatest 

 use to transport and to the community. 



In spite of the fact that the idea of the utilisation of 

 steam for giving rotary motion is old, its commercial 

 adaptation in the turbine is modern. Rarely, if ever, 

 has there been such a direct and instantaneous applica- 

 tion of science to practice. We are too close at present 

 to the matter to realise what a change has taken place 

 in the world owing to the introduction of the steam 

 turbine. One realises the work done by De Laval, 

 Curtiss, Rateau, and the brothers Ljungstrom, but the 

 name which will always be associated with the steam 

 turbine as firmly as that of James Watt is with the 

 inception of the steam engine is that of Sir Charles A. 

 Parsons. The success of his work is due to his applica- 

 tion of scientific principles to the many points of the 

 turbine and its accessories. Apart from its application 

 to marine work, it has made possible the economical 

 production of electrical energy, which is doing so 

 much, and will do so much more in the future, for rail 

 transport. 



The last means of propulsion that I can deal with is 

 the internal-combustion engine. This, as we almost 

 universally have it to-day, is the result of the cycle 

 adopted by N. A. Otto in his gas engine in 1876. Here 

 again the engines we have are the result of careful and 

 studied investigation, and the advance made has been 

 so much more rapid than in the case of the steam 

 engine and electrical machinery because of the more 

 advanced state of scientific knowledge. 



In relation to transport the work has proceeded on 

 two distinct lines, the Daimler and the Diesel engines. 

 In 1885 Gottlieb Daimler produced the engine associated 

 with his name, which utilises a light spirit supplying 

 a carburetted air for the explosive mixture for the 

 cylinder. The development of this engine has itself 

 proceeded in two directions. In one it has been made 

 very much more flexible and silent in its adaptation to 

 motor-car work, while in the other the great desider- 

 atum has been lightness and in association with the 

 improvements in the necessary materials has rendered 

 possible the aeroplane as we have it to-day. In both 

 cases the development to the degree reached has been 

 due to a careful study primarily of the pressures, com- 

 pression, and composition of the mixture. 



The Diesel engine was invented in 1894 by Rudolph 

 Diesel, and works by the injection of oil or pulverised 

 fuel into the engine cylinder. Its development has 

 taken place both on the four- and two-stroke cycle, 

 and although considerable progress has been made 

 with land engines, it has been used chiefly for marine 

 transport. 



The internal-combustion engine has not been largely 

 used for rail transport owing to its comparatively high 

 cost of fuel per horse-power and its lack of flexibility.- 

 The latter is particularly the case when one remembers 

 the high torque desirable, which can be attained in 

 both the steam and electric locomotives in starting. 



NO. 2813, VOL. I 12] 



The early efforts of Hulls have been mentioned, and 

 it was only natural that the work of Watt on land 

 should be followed by application of the new power 

 available to propulsion on the water. Although the 

 growth after the work of Symington, Fulton, and Bell 

 may have seemed to be slow, it was continuous, and 

 constant experiments and research were made both in 

 marine engines and in their application. Saving of 

 fuel has played a much more important part here than 

 with the locomotive, and since more space was available 

 and greater power required, the advantages of the 

 expansion of steam were rendered more imperative 

 and had greater scope than in the other long-established 

 method of mechanical transport. The great advance 

 came with the turbine, and it is interesting to notice 

 that whereas in early days engines were geared up, 

 most of them now are geared down to the screw. 

 Scientific methods have been applied to all those 

 details of measurement and experiment that have led 

 to transport by sea being carried on at increased speed 

 and with decreased cost per ton carried. The applica- 

 tion of liquid fuel and the introduction of Diesel engines, 

 both with the object of increasing the space available 

 for cargo, have been carried out on true scientific lines. 



Of transport by road it may be said that its com- 

 mercial inception came at a time when scientific know- 

 ledge was well advanced, and its progress was in 

 consequence more rapid. The development of the 

 motor-car engine is a case of the careful application 

 of the fundamental principle developed with ever- 

 increasing care until we get engines as noiseless, as 

 efTicient, as trustworthy, and as flexible as we have 

 them to-day. 



Much could be said of the indebtedness of aeronautics 

 to science, but I will only speak of the aeroplane. It 

 was not until the development of the internal-com- 

 bustion engine that the matter became really practical. 

 The War was naturally a great incentive to the advance- 

 ment of our knowledge of aeronautics. In the means 

 of propulsion, research has given an engine of such 

 size and so light in weight per horse-power that 

 what was a laboured struggle against the effects of 

 gravity has changed into the ability to rise at con- 

 siderably more than 1000 feet per minute to heights 

 where the rarefaction of the atmosphere renders it 

 necessary for oxygen for breathing to be obtained 

 artificially. The safety of flying as the result of the 

 work of Busk has rendered the machines stable even 

 in such a medium as the air. There is no greater 

 example of the indebtedness of transport to science 

 than the rapidity with which the possibilities of trans- 

 port by air have advanced. 



The other point I would deal with in some detail is 

 the question of materials. We, to-day, have no basic 

 metal or material which was not known when transport 

 first turned to mechanical methods for assistance. 

 The change which has come about has been as largely 

 due to the advances made in metallurgy as to the 

 inventions in mechanics that have led to the improve- 

 ments in means of propulsion and in machinery. The 

 early builders of steam engines were not only troubled 

 through inability to get their engines machined 

 properly, but also with the difficulties of obtaining 

 suitable material for the parts they required. Steel 

 has been known for thousands of years, but its rapid 



