196 



NATURE 



[April 24, 19 13 



unification of engineering and architecture as com- 

 ponent parts of one calling. Our contemporary con- 

 siders that the engineer should have a preliminary 

 training in architecture, and that the architect would 

 be the better artist if he had studied something of the 

 principles which underlie engineering, instead of 

 going through the world content to hoe his own 

 furrow irrespective of the general field. 



Engineering for April 18 contains a very full illus- 

 trated description of the new Cunard liner Aquitania, 

 which is being built and engined by Messrs. John 

 Brown and Co., Ltd., of Clydebank. This vessel is 

 the largest ship yet built for the express service to 

 New York. The following are the principal dimen- 

 sions : — Length over all, 902 ft. ; breadth, 97 ft. ; 

 depth, 64 ft.; displacement, 49,400 tons; shaft-horse- 

 power of the four-screw steam turbines, 60,000; 4230 

 passengers and crew are provided for. There are 

 forty-one watertight compartments in the double 

 bottom, and eighty-four watertight compartments in 

 the moulded structure of the ship above the double 

 bottom, formed by transverse and longitudinal bulk- 

 heads and watertight decks. The transverse bulk- 

 heads have been carried up to an unusual height. 

 The conditions are such that should the fore part of 

 the ship for the first five compartments, or the after 

 part of the ship for the six after compartments, or the 

 five centre compartments, be open to the sea, the ship 

 would still remain in a perfectly stable condition. To 

 render possible the launching and navigation of the 

 vessel to the sea, it has been necessary to widen and 

 deepen the channel of the River Clyde, a work which 

 will be of lasting benefit to navigation. The ship 

 was launched successfully on Monday last. 



In the announcement of Canadian tide tables made 

 in Nature of March 27 (p. 95), it was implied that 

 they are issued l>\ the Government Printing Bureau 

 at Ottawa, whereas, Mr. VV. Bell Dawson writes to 

 point out, they are merely printed there, and are 

 prepared and issued under his direction from the 

 office of the Tidal and Current Survey, Ottawa. It 

 may here be mentioned that the Tide Tables are 

 issued in two series, which refer to eastern Canada 

 and the Pacific respectively, the tides of two oceans 

 3000 miles apart, on opposite coasts. The work of 

 the Canadian Survey is thus very extended, and the 

 limited staff which carries it on is beginning further 

 investigation in Hudson Bay, an area much larger 

 than the North Sea, and quite as complex in its tides. 



OUR ASTRONOMICAL COLUMN. 



The Solar Union at Bonn. — The fifth meeting of 

 the International Union for Cooperation in Solar 

 Research will be held in the Physical Institute of the 

 Bonn University on July 31 next, and a preliminary 

 programme for that occasion has now been circu- 

 lated. On the evening of July 30 a reception will 

 be held in the large hall of the reading and recreation 

 society, and the mornings of July 31, August 1 and 2, 

 and afternoons of the two former dates, will be de- 

 voted l" the discussions. The afternoon and evening 

 of August 2 and the whole day of August 3 will be 

 taken up with a visit to Cologne, a reception being 

 given in the hall of the Giirzenich at the invitation of 

 the citv of Cologne, and probable alternative excur- 

 NO. 2269, VOL. 91] 



sions to (1) motor through the Eifel to the valley of 

 the Mosel, and (2) tour in the Siebengebirge. August 

 4 and 5 will see the resumption of the meetings, and 

 the afternoon of the latter date may be employed in a 

 steamer trip on the Rhine. In addition to the above, 

 Prof. Kiistner will receive the members at the 

 observatory on the afternoon or evening of August 1, 

 Prof. Karl Hausmann invites them to visit the 

 Technical High School at Aachen, and the Astro- 

 physical Observatory at Potsdam invites members for 

 August 11. 



A Case of Large Parallel Proper Motion. — Dr. 

 Ragnar Furuhjelm, of the Helsingfors Observatory, 

 communicates to the Astronomische Nachrichten 

 (No. 4642, p. 179) an instance he has found of two 

 stars fairly wide apart having the same velocity and 

 direction of proper motion. The stars in question are 

 a double star, BD + 45 4408 and No. 12740 in Burn- 

 ham's catalogue (8-3 m. and 83 m., a = oh. om. 23s., 

 8=4-45° r 5 - 5i 1900-0), the proper motion of which 

 was earlier known and measured, and a star of the 

 magnitude 9-5 m., its distance from the above binary 

 being about 5-5 minutes of arc. Dr. Furuhjelm gives 

 in detail the measures he made of both these stars on 

 several plates which he had taken at different times 

 in that region, and deduces the value of 09" for the 

 proper motion of the system, and 32758" and 254° 

 13-7' for the distance and position angle of stars. 

 Finally, he directs attention to another similar case 

 of large parallel proper motion as is exhibited in the 

 stars A Ophiuchi and 30 Scorpii, which are about 

 122' apart, and undergo a proper motion of 1-25". In 

 this instance also one of the stars is a double with 

 a distance of 4-2". Such systems form important 

 objects for study. 



The Solar Rotation in 191 i. — In the March num- 

 ber of The Astrophysical Journal (vol. xxxvii., No. 2) 

 Messrs. J. S. Plaskett and Ralph E. DeLury describe 

 and give the results of their very thorough investiga- 

 tion relating to the spectroscopic determination of the 

 solar rotation. The work was carried out at the 

 Dominion Observatory at Ottawa, the observatory 

 having undertaken this programme of work on the 

 lines determined by the International Union for 

 Cooperation in Solar Research. The instrumental 

 equipment at the Ottawa Observatory is of first-rate 

 quality, and is all that is needful for the research 

 which has been so successfully brought to an issue. 

 The communication in question is of considerable 

 length, and the authors describe and discuss the diffi- 

 culties met with as regards personalities in measure- 

 ment, instrumental errors, &c. The chief conclusions 

 to which thev ultimately reached were that the values 

 they deduced for the solar rotation could be repre- 

 sented by formulas which were in exceedingly good 

 agreement with those obtained by Duner and Adams 

 (iqo8), except for a small and nearly constant angular 

 difference. The absolute velocity of the solar rotation 

 seems to be uncertain by a small amount, amounting 

 to 2 or 3 per cent., due, as they suggest, to personal 

 differences in the habit of measurement of the rota- 

 tional displacements on the plates. No systematic 

 differences of velocity were found for different 

 elements, although they discussed 3000 residuals from 

 different lines and elements. It is of interest to 

 give here the different formulae for the rotation as 

 deduced by the authors and previous investigators : — 

 Aneular velocity. 



Duner ... 10-60° + 4-21° cos 2 <t> 



Halm 12-03° + 2-50° cos 2 



Adams (1908) 10-57° + 4-04° cos 2 



Adams (mean) 1 1-04° + 3-50° cos 2 # 



Plaskett (191 1) ... 10-32° + 405° cos 2 ^ 



DeLury (191 1) ... ... 10-04° + 4-00° cos 2 £ 



