In the history of the steamship during the short space of time that she has been employed, the changes in connection with her have followed with singular celerity. We have, during the previous pages, witnessed in the material of which she is built the gradual transition from wood to iron and steel; we have seen how steam pressures became greater, and the ensuing introduction of the compound system, the triple-expansion and the quadruple. We have also watched the change from paddle-wheels to a single screw, and thence to twin-screws. Each change has seemed to be so excellent in its nature, so beneficial in results, that almost on each occasion we might have thought that finality had been reached. At times our minds have been wearied with the constant reiteration of the latest wonders, and our imaginations have found some difficulty in responding to the demands which one invention after another has put forward. It has all happened within so short a time, and on a scale of such unheard-of magnitude, that scarcely have we been able to find expressions adequate to our subject. But now we enter upon what is the most wonderful of any period since the steamship came into the world, and for this we have to thank the introduction of the turbine, merely the beginnings of which we are now watching; whose influence, not merely in the engineering world generally, but in the domain of the steamship particularly, is already marking, in the most certain manner, a distinct cleavage between the things of yesterday and those of to-morrow. The turbine is only in its infancy, yet since its infantile influence has caused already so great a revolution, one hesitates to reckon what it will do before it is as old as the old-fashioned reciprocating engine, whose history we have outlined. Its modern practical invention is due to two men, one an Englishman, the other a Swede, who during the early ’eighties made their systems public. The latter is Dr. Gustav de Laval; the former the Hon. Charles Algernon Parsons, son of the Earl of Rosse, who after a distinguished career at Cambridge, where he graduated as eleventh Wrangler, brought out this new method in 1884. Five years later Dr. de Laval, working at the same problem, developed a somewhat similar engine. We have spoken of the _modern_ invention advisedly, for there is nothing new under the sun, and we shall see that the bare principle is hundreds of years old. In its simplest form, the turbine is similar to a water-wheel, a jet of steam taking the place of water. As far back as 1629, Giovanni Branca, an Italian engineer, had suggested much the same thing, and if the reader will now refer to the illustration opposite he will be able to gain some idea of the form in which his idea took shape. [Illustration: GIOVANNI BRANCA’S STEAM ENGINE (1629). The simplest form of Turbine. _From the Exhibit in the Victoria and Albert Museum._]