594 



NA TURE 



[April 20, 1905 



In 1904, when the author took comparison photographs 

 from nearly the same spot, this large crater was almost 

 entirely filled up, and the slope of the Sciara was continued 

 upwards, so that the cone of ejecta overtopped and was 

 visible behind the eastern Torrella. The activity in this 

 eastern part of the crater still maintained the same quiet 

 character as in 1888. The whole area constantly emitted 

 vapour ; there was more than one bocca visible, but they 

 were quite small and only gave very feeble explosions, and 

 these with a rhythm quite independent of those at the 

 western part of the crater. 



Fig. 2, taken by the author on April 20, 1904, from a 

 point to the west of the crater, and consequently in almost 

 exactly an opposite direction to Fig. i, shows the condition 

 of the western part of the crater sixteen years later. The 

 conspicuous rock to the right of the plate is the western 

 Torrella, behind which, in 1888, wa's the great crater 

 above referred to. The bocca to the left, from which the 

 explosion is taking place, is shown in some of the earlier 

 photographs as situated on the edge of the large crater 

 at its junction with the Sciara. The great crater is now 

 seen to be filled up by ejecta which prolong the slope of 

 the Sciara upwards over what was previously its site, 

 while the bocca itself remains in all probability really in 

 its former position, though apparently on the slope of the 

 Sciara instead of on its edge. 



It will be interesting to future visitors to see whether 

 the volcano will continue to prolong the slope of the Sciara 

 much further upwards, or whether a paroxysmal explosion 

 will occur which will clear the great crater again. 



The paper in the Geographical Journal is illustrated 

 with twelve photographs and a map showing these and 

 other points more in detail. 



THE INSTITUTION OF NAVAL ARCHITECTS. 

 'T'HE annual spring meeting of the Institution of Naval 

 Architects was held last week, commencing on 

 Wednesday, April 12, and being continued over the two 

 following days. The president of the institution, the Right 

 Hon. the Earl of Glasgow, occupied the chair. A very 

 full programme had been arranged, there being no less 

 than fifteen papers set down for reading and discussion, 

 and there was also the presidential address. 



The first business after the usual formal proceedings 

 was the reading by the secretary, Mr. R. W. Dana, of 

 the report of the council. By this it appeared that the 

 institution is in a prosperous condition, both in regard to 

 finance and membership. Reference was made to the pro- 

 posed foundation of an experimental tank for the purpose 

 of scientific investigation of problems connected with ship 

 design. It will be remembered that it was proposed, at 

 the initiative of Mr. A. F. Yarrow, Dr. Elgar, Sir William 

 White, and other prominent members of the institution, 

 that an institution tank should be founded in connection 

 with the National Physical Laboratory. Such a tank, de- 

 voted to research of a scientific nature, would be of great 

 benefit to the ship-building industry, and would do much 

 to raise naval architecture to a higher plane by the 

 substitution of scientific principles for those empirical 

 methods upon which ship designers too largely have to 

 rely. It is much to be regretted, therefore, and not very 

 creditable to an important and wealthy industry, that the 

 appeal made by the council of the institution has met 

 with so poor a response. Only six thousand pounds out of 

 the fifteen thousand pounds needed has been underwritten, 

 so that the project is shelved for the present. In spite of 

 the enormous preponderance of the ship-building interests 

 of this country, there are but two experimental tanks in 

 the kingdom. One is the properly of the Government, and 

 is devoted wholly to the Royal Navy, the other being the 

 property of a private firm of ship-builders on the Clyde. 

 Both these tanks are devoted entirely to what is known 

 as " practical work," that is to say, they attack subjects 

 piecemeal, and therefore in a more or less empirical 

 fashion. They have no time for ordered investigation of 

 fundamental principles, upon a knowledge of which, alone, 

 can a useful superstructure of applied science be raised. 

 The tanks are not to blame for this. They were estab- 

 lished for a definite purpose, which they admirably fulfil. 



In the presidential address Lord Glasgow, among other 

 NO. 185 I, VOL. 71] 



subjects, referred to the spread of the steam turbine for 

 marine propulsion, alluding more particularly to the recent 

 trials of H.M.S. Amethyst. Some interesting comparisons 

 were made between the performances of this cruiser, which 

 is fitted with steam turbines, and the Topaze, a similar 

 ship in all respects, excepting that she has ordinary crank 

 and cylinder engines. As is well known, the steam turbine 

 is less " flexible," to use an expression that has come into 

 use, than the reciprocating engine ; that is to say, its 

 efficiency falls off rapidly when it is run at lower powers 

 than that for which it was designed to give maximum 

 efficiency. This point was well illustrated during the trials 

 of the Amethyst and the lopase by the coal consumption, 

 the figures being given in Lord Glasgow's address. The 

 steam turbines of the Amethyst drove her at 235 knots, 

 545 per cent, faster than her sister ships with recipro- 

 cating engines. At the higher speeds the turbine engines 

 appeared decidedly more economical ; at lower speeds the 

 reciprocating engines had the advantage. At 10 knots a 

 ton of coal would carry the .■Imethyst 742 miles, or the 

 Topaze 9-75 miles. From this speed upwards the margin 

 in favour of the reciprocating engines decreased, until the 

 consumption curves would cross at a little above 14 knots, 

 when approximately 6i miles would be steamed on a ton 

 of coal. At a speed of 20 knots the Amethyst ran 422 

 miles, and the Topaze 29 miles, per ton of coal burnt. 

 At 23-6 knots, a speed the Topaze did not reach, the 

 .imethyst w^ould steam a little more than 2 miles per ton 

 of coal. If it may be allowed that about 14 knots is the 

 lowest speed at which these cruisers could be advan- 

 tageously run in time of war, the steam turbine has a 

 marked advantage for warlike purposes ; but it might 

 lead to higher coal consumption in time of peace. 



The first paper taken was a contribution by Mr. W. E. 

 Smith, of the Admiralty, upon the design of the Antarctic 

 exploration vessel Discovery. This was a single screw 

 wooden steamer 175 feet long, 34 feet wide, and about 

 1620 tons displacement. The propeller was so arranged 

 as to be disconnected from the shaft and lifted 'into a 

 well, after the manner adopted in the old steam frigates. 

 The rudder was also arranged to be readily unshipped. 

 The scantling of the hull was massive, but in general 

 plan followed the designs adopted in the days of wooden 

 construction. The vessel was fully rigged as a barque. 

 The fitting of a magnetic observatory was one of the 

 special features of the design. The work done here w^ns 

 of great magnitude, and the observations taken are now 

 being analysed by Captain Chetwynd, the .Admiralty 

 superintendent of compasses. No magnetic metal was 

 allowed within a radius of 30 feet of the observatory. 

 Main shrouds were of hemp, the lanyards being rove 

 through wooden dead eyes. Great care was taken to lag 

 the living part of the ship so as to economise coal. Pro- 

 fessional details of the design were dealt with at some 

 length. In the discussion on this paper. Sir Clements 

 Markham gave some historical details of former Polar 

 expeditions, and dwelt upon the advantage of having a 

 ship expressly built for the purpose. Captain Scott, who 

 was in charge of the expedition. Sir William White, and 

 -Admiral Fitzgerald also spoke. 



The next paper was by Colonel Soliani, of the Royal 

 Italian Navy, and gave technical details of the Japanese 

 war vessels Kasuga and Nisshin, both built in Italy. .A 

 paper by Mr. H. Rowell giving an account of the Russian 

 Volunteer Fleet followed. 



The second day of the meeting opened with a paper by 

 Prof. J. H. Biles, who gave details of trials made 10 test 

 the strength of a torpedo-boat destroyer supplied for the 

 purpose by the Admiralty. The vessel was placed in dry 

 dock, being supported on cradles near the ends, so as to 

 produce sagging stresses, and in the middle in order to 

 induce hogging. The experiments were part of the in- 

 vestigation of the Admiralty Destroyer Committee. The 

 results w-ere set forth at considerable length in the paper 

 and in the large number of diagrams which accompanied 

 it. It will be sufficient to say here that the actual results 

 observed on these practical trials established the usual 

 methods of calculation as affording a good margin of 

 safety, the stresses in the observed results being con- 

 sistently below those calculated by the formula? commonly 

 used bv naval architects. 



