June 25, 1891] 



NATURE 



181 



ward. Still, it was the Great Harry, or one of her con- 

 temporaries, by means of which this new feature in seaman- 

 ship was inaugurated ; a feature by which the great middle 

 period in the world's history of naval warfare was created, 

 and which enabled the sailors of those times to make a 

 distinct advance upon the lessons taught them by their in- 

 structors in the art of shipcraft, the Phoenicians, Romans, 

 and Scandinavians. It would have been well if we had 

 improved on our predecessors in other nautical matters as 

 well ; and we then should not have had, even in the 

 present century, our shipwrights attaching lead sheathing 

 to ships' bottoms with iron nails. The Romans used 

 copper fastenings when they lead-covered the under-water 

 part of their vessels. 



There are but three models of seventeenth-century 

 ships in the Exhibition, but one of these is a vessel that 

 forcibly illustrates, by contrast, the mutability of the 

 present age. The Royal William was designed by the 

 first great naval architect, Phineas Pett— whose name 

 might almost more appropriately have been given to the 

 Models Gallery than that of Seppings — and was built at 

 Chatham in 1670. She was originally a three-decker, 

 carrying one hundred guns, but in 1757 she was cut 

 down to a ship of 84 guns, and was finally broken up in 

 1813 — a fact duly recorded by the present Director of 

 Naval Construction, Mr. W. H. White, in his delightful 

 lecture on "Modern War Ships," delivered a few years 

 ago at the Mansion House. The Royal William must 

 not, however, be taken as an example of the endurance 

 of ancient materials so much as of the slow changes in 

 design which characterized the proceedings of our an- 

 cestors. The original material part of the Royal William 

 only lasted twenty-two years, for she was rebuilt, we are 

 told, in 1692, and again in 17 19 ; so that in this respect 

 she compares unfavourably with so modern a vessel as 

 our first ironclad, the Warrior, which has only recently 

 been taken out of the Navy after a service career of not 

 far from 30 years. Even now the Warrior has not been 

 removed from the Navy list because she has become 

 worn out, but simply because she has become obsolete. If 

 we could reach finality in design — if the inventive brain 

 would stagnate—there is no reason why the modern 

 iron-built warship should not outlast its wooden prede- 

 cessor by almost as great an extent as it exceeds it in 

 power of destruction. It is true the natural life of the old 

 ships was a long one. The Victory was forty years old 

 when she was engaged in the battle of Trafalgar, and 

 had seen much active service, having been launched at 

 Chatham in 1765 ; but then she had been laid by as worn 

 out in 1 801, and it was only after extensive repairs that 

 she was made fit for sea. A year or two ago, it will be 

 remembered, she was found to be so rotten that she 

 would have sunk at her moorings had she not been taken 

 into dock and in part rebuilt. On the other hand, there 

 is no reason why an iron ship should not last, provided 

 she were properly painted and kept up, perhaps until the 

 era when warships will have become relics of a barbarous 

 past. The expression " properly painted " must be 

 here taken in its literal sense ; and with regard to steel 

 ships due steps must be followed to remove mill-scale, a 

 precaution which has not always been taken of late, as 

 quite recent mishaps have testified. 



Passing from hulls to motive power, we find the same 

 governing principles as to durability of material and im- 

 permanence of design more strongly emphasized in the 

 practice of to-day compared with that of the naval era 

 which closed with the introduction of steam and iron 

 hulls. With comparatively small variations in detail the 

 rig of war ships has remained unchanged from the days of 

 Pett down to those within the memory of men still living. 

 The Henri Grace a Dieu shows a distinctly mediaeval rig 

 —although her fighting-tops are ridiculously like those of 

 our very latest armour-clads— but it would take almost a 

 sailor's eye to point out the dift'erences in sail plan between 

 NO. I 130, VOL. 44] 



Vandevelde's beautiful painting of the Sovereign of the 

 Seas, " built in 1637," and the ships which appear on the 

 canvases of Stanfield, Turner, and Cooke. So much for 

 permanence of design with masts and sails ; with the 

 succeeding mode of propulsion, engines and boilers, we 

 find as striking a result in the opposite direction. Steam 

 machinery was first introduced into the Royal Navy in 

 small gun boats, and later in the paddle-wheel frigates, 

 but it was not until the screw was proved to be the 

 more effective instrument that even the most sanguine 

 engineers could hope that engines and boilers would 

 successfully rival masts and sails as a means of propul- 

 sion. We pass over, therefore, the unimportant era of 

 paddle-wheels, but even taking screw engines alone we 

 find that during the last forty years far greater changes 

 have taken place in the design of steam machinery than 

 characterized the arrangement of masts and sails duringthc 

 two hundred years elapsing between the time \X\e Sovereign 

 of the Seas was built and the practical introduction of 

 steam into the Navy ; indeed we might, without any great 

 fear of contradiction, go further and say that to the eye of 

 the engineer there is no greater affinity between the screw 

 engines of forty years ago and those of the present day, 

 than existed between the rigging of the ships of the Norse 

 sea-kings and those of almost our own day, putting on 

 one side only the element of size. The collection of 

 engine models in the Exhibition is far from complete, and 

 is not to be compared with that of ship models. There 

 is a good reason for this, as engineers work to draw- 

 ings, and models are seldom made excepting as records ; 

 whilst their cost is so great as to render them available 

 only for very rich firms. The collection of models shown 

 by Messrs. Maudslay, Sons, and Field constitute the 

 greater part of the historical collection in the Exhibition. 

 Here may be seen representations of the first types of 

 steam-engine introduced into the Navy ; and we think a 

 comparison of the early engines in this collection with, say, 

 the magnificent model of the Sardegnd's engines, shown 

 by Messrs. Hawthorn, Leslie, and Co., will bear out the 

 remarks we have made. What path the progress of 

 marine engineering wiU follow in future it is difficult to 

 forecast. The inventions of to-day always seem to have 

 reached finality, but it is difficult to imagine that any 

 fundamental change can be effected so long as we retain 

 the use of steam as a vehicle for the conversion of heat 

 into work. It may be that a little engine shown in the 

 Exhibition — Priestman's oil engine— may contain the germ 

 of a principle upon which marine engines may be de- 

 signed in future, and that before we have got far into the 

 twentieth century the marine boiler, with all its costliness 

 and complication, may have become as much a relic of 

 the past as the pole masts and uncouth sails of the Great 

 Harry. Before that time arrives, however, the four-stroke 

 cycle will have to be superseded. 



It is, however, the steam boiler, rather than the engine, 

 which has governed the design of ship machinery. Forty- 

 to forty-five years ago, steam pressures were not generally 

 higher than 5 to 8 pounds per square inch. With 

 the introduction of tubes in place of flues, which took 

 place between 1840 and 1850, the working pressure rose 

 to 15 pounds per square inch. The square box boiler 

 was in use, and with that type the working pressure was 

 limited to about 30 pounds per square inch, or not much 

 beyond, unless the staying of the flat surfaces was carried 

 to an undesirable extent. With such a limit of pressure, 

 the simple expansion engine was, properly, the usual type, 

 but when the cylindrical marine boiler was introduced, 

 the average steam pressure quickly rose to 60 pounds to 

 the square inch, and the compound engine naturally fol- 

 lowed. The surface condenser formed a necessary part 

 of this step in advance, for, with the higher temperature 

 due to the increased steam pressure, it was impossible to 

 pass large quantities of salt water through the boilers 

 without rapidly scaling them up. For some time the 



