March 6, 1890] 



NATURE 



429 



has found that in 1 886 this comet must have approached near to 

 Jupiter, and his investigations seem to show that it is identical 

 with the lost comet of Lexeli. 



Comet e 1889. — Discovered by Mr. Davidson at Branscombe, 

 Mackay (Queensland), on July 22, and visible to the naked eye 

 at first as a star of the fourth magnitude. It moved rapidly 

 towards the north, and at the same time diminished in bright- 

 ness, remaining visible, however, up to November. 



Comet f 1889. — Discovered by Mr. Lewis Swift at Rochester, 

 U.S., on November 17. From observations extending over 

 twenty days, Dr. Zelbr was led to conclude that the comet was 

 periodic, the time of revolution being 6'9i years. 



Comet g 1889. — Discovered by M. Borrelly at Marseille, on 

 December 12. It was then feeble, but rapidly increased in 

 brightness. Although the declination of this comet on discovery 

 was + 48° 55', it moved so quickly towards the south, that it was 

 lost to our latitudes about January 10, 1890. The first observa- 

 tions fixed the perihelion passage at January 26, 1890. 



Six asteroids were discovered in 1889, viz. : — 



y^ Discovered by M. Charlois at Nice on January 28. 

 (^ ,, ,, ,, ,, February 8. 



@ ., ,, „ » May 29. 



@ „ ,, „ ,, August 3. 



^•wy ,, ,, M. J. Palisa at Vienna on August 3. 



(^ ,, ,, Dr. Peters at Clinton, U.S., October 13. 



Mass of Saturn. — The Transactions of the Astronomical 

 Observatory of Yale University, vol. i. part ii., contains some 

 researches with the heliometer by Mr. Asaph Hall, for the 

 •determination of the orbit of Titan and the mass of Saturn. 



From observations made at the oppositions of 1885-86, 18S6- 

 87, the mean value of the semi- major axis of Titan's orbit was 

 determined as — 



1 76" -570 ± o"-0243 ; 



and the mass of Saturn — 



I 



3500-5 ± Vi^ 

 the sun being unity. 



Struve showed that the value found by Bessel from Titan 

 should be 3502*5, while the values found by Struve himself from 

 lapetus and Titan are respectively 35oo'2 ± 0*82 and 34957 

 ±;i"43. Prof. Hall, with the great Washington refractor, found 

 from lapetus by means of differences of right ascension and 

 declination, the mass 3481 '2 ± 0*65, and by distances and posi- 

 tion-angles 348i'4 ± 0'97 ; from Titan the values corresponding 

 to the same methods are 3496*3 ± 1*84, and 3469*9 ± i*49, but 

 there seem to be grounds for questioning these results, so 

 discordant with those found by Struve, and at Yale College. 



THE OPENING OF THE FORTH BRIDGE. 



A/rUCH interest was excited all over the country by the open- 

 ing of the Forth Bridge onjTuesday. The ceremony was 

 simple, and all the arrangements were carried out successfully. 

 There was no rain, and although the wind blew stiffly, it was 

 " comparatively mild." The special train conveying the directors 

 and invited guests left the Waverley Station, Edinburgh, in two 

 portions, the first at 10.45, the second, to which the Royal 

 carriages were attached, ten minutes later. At the Forth Bridge 

 Station Sir John Fowler, Mr. Benjamin Baker, Mr. William 

 Arrol, Mr. Phillips, and other gentlemen connected with the 

 building of the bridge, awaited the arrival of the Royal party 

 from Dalmeny. By the special desire of the Prince of Wales, 

 who wished to have an opportunity of examining some details of 

 the structure, the Royal train steamed very slowly across the 

 bridge. As seen from the shore, the long train of large saloon 

 carriages is said to have looked like ' ' a mere toy as it passed 

 through the stupendous framework of tubes and girders at 

 Inverkeithing." From the North Queensferry Pier the steam 

 launch Dolphin conveyed the Royal party and the directors 

 over the Firth, so that the bridge might be seen from the 

 sea ; and another vessel followed, containing the rest of 

 the company. Both vessels steamed out to the middle 

 of the Firth ; and, according to the Times, the view 

 was much enjoyed "as each cantilever was passed in suc- 

 cession, the junction of the girder bridges with the cantilever 



arms being specially noted." Afterwards, the bridge was re- 

 crossed, and in the middle of the north connecting girder the 

 train stopped to allow the Prince of W'ales to perform the cere- 

 mony of driving the last rivet. " A temporary wooden staging," 

 says the Times, " had been erected there, and upon it His Royal 

 Highness stepped, along with Lord Tweeddale, Lord Rosebery, 

 and Mr. Arrol. The hydraulic rivetter was swung from one of 

 the booms, the pressure being supplied from an accumulator at 

 Inchgarvie. Two men were placed on the boom below to 

 manipulate the machine. The gilded rivet having been placed 

 in the bolt-hole, and the silver key having been handed to His 

 Royal Highness by Lord Tweeddale, the Prince, with Mr. 

 Arrol's assistance, finished the work in a few seconds, amid 

 cheers. The rivet is in the outside of the boom, and holds 

 together three plates. Around its gilded top there is an inscrip- 

 tion stating that ; it is the 'last rivet, driven in by His Royal 

 Highness the Prince of Wales, 4th March, 1890.' The train 

 stopped a second time at the south great cantilever pier, where 

 another platform had been erected, upon which several ladies 

 were standing. Here the Prince again left the train, at half-past 

 I o'clock, to make the formal declaration of the opening of the 

 bridge. As the wind was blowing a perfect gale, so that His 

 Royal Highness had difficulty in retaining a steady foothold, it 

 was impossible to make a speech. He therefore simply said i 

 * Ladies and Gentlemen, I now declare the Forth Bridge open. ' 

 Hearty cheers greeted the announcement, and, the Prince having 

 returned to his carriage, the train moved slowly along to the 

 Forth Bridge Station." 



At 2 o'clock a banquet was given in the model-room at the 

 bridge works, the chair being occupied by Mr. M. W. Thomp- 

 son. The Prince of Wales, responding to the toast of '* The 

 Prince of Wales and other members of the Royal Family," spoke 

 as follows : — 



" I feel very grateful for the kind words which have fallen from' 

 the chairman in proposing the toast, and I thank you all most 

 heartily for the cordial way in which you have received it. The 

 day has been a most interesting day to all of us, and especially 

 so to me, and I feel very grateful that I have been asked to take 

 part in so interesting and important a ceremony as the one at 

 which we have all assisted. I had the advantage, nearly five 

 and a half years ago, of seeing the Forth Bridge at its very com- 

 mencement, and I always looked forward to the day when I 

 should witness its successful accomplishment. I may perhaps 

 say that in opening bridges I am an old hand. At the request 

 of the Canadian Government I performed the opening ceremony 

 30 years ago of opening the Victoria Bridge over the St. Law- 

 rence at Montreal, putting in the last rivet, the total of rivets 

 being one million. To-day I have performed a similar ceremony 

 for the Forth Bridge, but on this occasion the rivets number 

 nearly eight millions instead of one million. The construction 

 of the bridge has been on the cantilever principle, which has 

 been known to the Chinese for ages, and specimens of it may be 

 seen likewise in Japan, Tibet, and the North-West Provinces of 

 India. .Work of this description has hitherto been carried out- 

 on small dimensions, but in this case the engineers have had to 

 construct a bridge in 30 fathoms of water, at the height of 1 50 feet 

 above high water mark, and crossing two channels, each one- 

 third of a mile in width. Had it not been for the intervening 

 island of Inchgarvie the project would have been impracticable 

 It may perhaps interest you if I mention a few figures in con- 

 nection with the construction of the bridge. Its extreme length,, 

 including the approach viaduct, is 2765 yards, one and one-fifth 

 of a mile, and the actual length of the cantilever portion of the 

 bridge is one mile and 20 yards. The weight of steel in it 

 amounts to 51,000 tons, and the extreme height of the steel 

 structure above mean water-level is over 370 feet ; above the 

 bottom of the deepest foundation 452 feet, while the rail-level 

 above high water is 156^ feet. Allowance has been made for 

 contraction and expansion and for changes of temperature to the 

 extent of one inch per 100 feet over the whole bridge. The wind- 

 pressure provided for is 56 lb. on each square foot of area, amount- 

 ing in the aggregate to about 7700 tons of lateral pressure on 

 the cantilever portion of the bridge. About 25 acres of surface 

 will have to be painted with three coats of paint. As I have 

 said, about eight millions of rivets have been used in the bridge,, 

 and 42 miles of bent plates used in the tubes, about the distance 

 between Edinburgh and Glasgow. Two million pounds have 

 been spent on the site in building the foundations and piers ; in 

 the erection of the superstructure ; on labour in the preparation 

 of steel, granite, masonry, tinber, and concrete ; on tools, cranes, 

 drills, and other machines required as plant ; while about two- 



