56 



NATURE 



[July 13, 191 1 



amera having a U.V. 15 prism ; the scale of the latter 

 is such that the distance on the plat.; from 11(3 to lie is 

 3 mm. The outstanding features of the spectra are broad 

 bright hydrogen lines, and a very strong bright band which 

 Prof. Frost designates A 4640. On the Bruce spectrogram 

 (scale, 1 mm. = 26-0 A.U.) dark shadings and bright 

 maxima are suspected within these bright lines, and dark 

 lines are seen on the more refrangible edges, especially in 

 the cases of H0 and H7. The displacements of the lines, 

 if interpreted by line-of-sight motions, would indicate 

 velocities varying from —1300 to +760 km. per second. 

 Spectrograms taken on May 4 and 6 indicate a strengthen- 

 ing of the chief nebular line at K 500, thereby suggesting 

 that the change to the nebular state, apparently common to 

 all nova;, had set in. 



A number of observations of position, magnitude, and 

 colour of the nova are recorded by various observers in 

 No. 4509 of the Astronomische Nachrichten. 



The Tail of H alley's Comet. — As an extract from 

 No. 3 of del et Terre we have received a paper in which 

 Prof. Eginitis summarises the discussion concerning the 

 appearance of the tail of Halley's comet on the night of 

 May =0, iqio. Having demonstrated that an error of 

 observation, at Athens, is out of the question, he explains 

 the apparent digression between his observation and some 

 others by the suggestion that at that time the earth was 

 situated on, or very near to, the axis of the main tail. 

 Thus only the nucleus bounded by nebulosity would be 

 seen, and the form observed would be one that would 

 change rapidly as the angle under which it was seen 

 changed. The differences are thus reduced to a question 

 of perspective, and it is argued that this would change 

 quickly at that critical period. 



The Great Red Spot on Jupiter. — Mr. Stanley 

 Williams, writing to the Astronomische Nachrichten (No. 

 4507), confirms the abnormal change of longitude of the 

 Red Spot, which was observed by the Rev. T. E. R. 

 Phillips and others. In addition, he remarks upon the 

 great change in the visibility of the spot itself which has 

 recently taken place. For several years the spot has been 

 indistinct and not of its earlier characteristic red colour, 

 but lately it has been, to Mr. Williams, not only a com- 

 paratively conspicuous object, but also strongly coloured. 

 It would seem that the spot is now free from the over- 

 lying material which has for some time masked its 

 characteristic clearness and colour. Mr. Williams's transit 

 times, taken on May 10 and 17 and June 1 and 8, con- 

 firm the change of longitude, and show that the length of 

 the spot has not changed ; the difference of longitude, 

 — 7.7°, between June 1 and S, if real, is remarkable. 



Definition of the Term " Double Star." - Having for 

 some years been desirous of establishing a definite scope 

 for the term "double star," Prof. R. G. Aitken recently 

 prepared a scheme for this purpose and submitted it to 

 the chief double-star observers of the world. The majority 

 agreed that some restriction to the use of the term is 

 necessary, while others believe that the difficulties in 

 establishing a rigorous system would outweigh the 

 advantages accruing from its adoption. Prof. Aitkc n 

 publishes his scheme, and the correspondence respecting it, 

 in No. 4505 of the Astronomische Nachrichten. His 

 definition of a double star includes any two stars which 

 come within the following limits of distance: — 



t" if combined mag. of components is fail tpr th.m 1 1 v 



3" ., „ .. 9-° B-n. 



s" „ ,, lie, between 6'o and qv> 11 I >. 



10" „ ., 4-0 „ ... .. 



20" ,, .. .. 4-0 , 



40" ,, ,. it than 2 - o B.D. 



JUBILEE MEETINGS OF THE INSTITUTION 



OF NAVAL ARCHITECTS. 

 '"THE jubilee meeting of the Institution of Naval Archi- 

 tects opened on Monday evening, July 3, with a 

 reception by the president, the Marquis of Bristol, which 

 was attended by members and delegates from all parts of 

 the world. H.R.II. the Duke of Connaught took the chair 

 at the meeting on the morning of July 4 as honorary 



NO. 2176, VOL. 87] 



president of the congress, and the president's address was 

 delivered at this meeting. Reference was made to the 

 death of the late president, Lord Cawdor, whose 

 personality and zeal marked him out as a leader whom 

 men would be proud to follow. The present congress had 

 a twofold purpose — lo commemorate the jubilee of the 

 institution and to bring together from all parts of the 

 world the great leaders in this sphere of industrial activity. 

 The council desired to do honour to their guests from 

 abroad, and had determined to invite the following to 

 accept honorary membership of the institution, the 

 highest honour in their power to confer : — II. M. the King 

 ..I Norway, II.M. the King ..( Spain, 11. M. the King of 

 Sweden, il.I.Il. Prince Henry of Prussia, II. I. II. Arch- 

 duke Ferdinand, U.K. 11. the Duke ..I Connaught, U.K. II. 

 the Duke of Genoa, Prince Roland Bonaparte, Lord 

 Rayleigh, Admiral Dewey, Admiral Togo, and Admiral 

 Ijuin. 



Sir William II. While gave an interesting account of the 

 history of the Institution of Naval Architects, in which he 

 referred to Sir Nathaniel Barnaby, the only survivor of 

 the little group of men whose meeting on January 16, 

 1.S60, practically secured the establishment of the institu- 

 tion. Looking back upon work which has been done by 

 the institution, it may be claimed that the intentions of its 

 promoters, on the whole, have been well fulfilled ; in some 

 respects they have been surpassed. The meetings of the 

 institution have afforded exceptional opportunities for the 

 discussion of questions affecting the science and practice of 

 naval architecture and marine engineering, the construc- 

 tion of warships and of merchant ships, the shipbuilding 

 policy of Great Britain, the safety of life and property at 

 sea, the introduction of new materials of construction and 

 structural arrangements, the development of experimental 

 methods of research, the introduction of new methods of 

 ship calculations and design, and the discussion of new 

 inventions of various kinds. Before the institution was 

 founded, naval science had no home in England ; its 

 treasures lay scattered far and wide in the form of 

 memoirs and papers contained in the Proceedings of the 

 Royal Society or in other publications. Everything worthy 

 of publication now naturally finds its way to the Trans- 

 actions, and through them to naval architects, marine 

 engineers, and others interested in these subjects through- 

 out the world. Every great movement may be said to 

 have been chronicled for fifty years. 



Fifty years' architectural expression of tactical ideas 

 formed the subject of a paper by Admiral Sir Cyprian 

 Bridge. In the year 1S60 what may be called the seven- 

 teenth-century type of man-of-war was still represented in 

 the British Navy. The gun, as the weapon without a 

 rival, conspicuously dominated tactics. The great change 

 introduced in 1S71, the virtual abolition of the broadside 

 system of arming ships, occurred at a time when the con- 

 test between the gun and armour was in full progress. 

 Tactical considerations receded into the background. In 

 1871 we adopted as a weapon of war the Whitehead loco- 

 motive torpedo. It is a remarkable fact that the adoption 

 of this weapon and the limitation of a ship's gun-arma- 

 ment to a small number of the heaviest guns that she could 

 carry occurred almost simultaneously. We made no 

 tactical provision for dealing with torpedo attacks : reliance 

 was placed on passive defence arrangements exclusively. 

 The French were the first to break away from the posi- 

 tion above indicated. They had a vivid perception of the 

 great tactical principle that concentration "i the effect of 

 weapons should be the end aimed at, and that concentra- 

 tion of the weapons themselves is merely the means. 

 They armed their ships in accordance with this principle, 

 and other nations had to follow their example. The ships 

 launched or designed for our own navy during the last 

 ars of the nineteenth century and the first two or 

 three years of the twentieth supply monumental evidence 

 I the reviving, but far from dominant, influence of 

 tactics. 



Fifty years' changes in British warship machinery were 

 deall with by Engineer-Vice-Admiral Sir Henry J. Oram. 

 In [860 the Navy List included a total of 400 ships, having 

 1 collective indicated horse-power of 540,000. In iqio the 

 number of warships was 1585, of approximately 5,000,000 

 indicated horse-power. The founding of the institution 



