164 



NATURE 



[Dec. 19, 1889 



a AurigcE. 291 lines have been measured in the spectrum of 

 this star between A 410 and A 470, all of which appear identical 

 with solar lines. 



Magnitude and Colour of i\ Argus, — Observations of 

 this variable have been made at Cordoba since 1871, and some 

 comparisons made by Mr. Thome (Asir. Nachr, No. 2922) 

 show that it steadily decrea,sed in magnitude until about the end 

 of 1886, when a minimum of 7*65 was reached, and it is now 

 about 6'6. In 1843, Maclear gave the brightness of i\ Argus as 

 - I'D, or between that of Sirius and Canopus, so that the 

 variation in magnitude is 8 '5, and not 6 as heretofore assumed, 

 this variation, extending over 44 years, gives an average yearly 

 rate of diminution of o'2. 



It is interesting to note that the change in magnitude was 

 accompanied by a change in colour ; for although before mini- 

 mum the star was of a dull scarlet the colour became lighter, 

 until in June 1889 it was a bright orange. 



Orbit of Barnard's Comet 1884 II. — From an investiga- 

 tion of all the available observations of this periodic comet. Dr. 

 Berberich has computed the following elements (^5^r. A^«c/jr. , 

 2938-39). 



Epoch 1884 August l6'5, Berlin Mean Time. 



M = 35°9 59 49-13 



w = 301 I 58-63 



ft = 58 59-12 



1= 5 27 38-40 



<?> = 35 44 50-92 

 M = 65 7" -0839 ± o"-8876 

 log a = 0-4882572 

 Perihelion passage =: 1884 August 16-516543 

 Period = 1972-35 ± 2*66 days. 



It will be seen from the foregoing period, that the comet will 

 be at perihelion again in 1890 January 9-87. 



Algol. — At the meeting of the Royal Prussian Academy of 

 Sciences, held on November 28, Prof. Vogel gave the results 

 he had obtained from photographs of the spectrum of this 

 variable. Prof. Pickering had pointed out, some years ago, that 

 if the variation in stars of the Algol class were due to the transit 

 of a dark satellite across the disk of its primary, producing a 

 partial eclipse, then since in every case yet known the two 

 bodies must be close to each other, and of not very dispropor- 

 tionate size, the primary must revolve with very considerable 

 rapidity in an orbit round the common centre of gravity of the 

 two ; and, therefore, be sometimes approaching the earth with 

 great rapidity and sometimes receding from it. Six photographs 

 of the spectrum of Algol — obtained, three during last winter, and 

 three during the November just past — have shown that before 

 the minimum the lines of the spectrum of Algol are markedly 

 ■displaced towards the red, showing a motion of recession ; but 

 that after the minimum the displacement is towards the blue, 

 showing a motion of approach. Assuming a circular orbit for 

 the star, and combining the details given by the spectroscope 

 with the known variation of the star's light. Prof. Vogel derives 

 the following elements for the system of Algol : — 



Diameter of Algol 1,074,100 English miles. 



Diameter of the dark companion 840,600 ,, ,, 



Distance of centre... ... ... 3,269,000 ,, ,, 



Speed of Algol in its orbit 27 iniles per second. 



Speed of the companion in its orbit ... 56 ,, ,, 



Mass of Algol ^ of the sun. 



Mass of the companion ... ... ... ^ ,, ,, 



Speed of translation of the entire system l ., , 



towards the earth ^ __ | 2 miles per second. 



It will be seen that the density both of Algol and its com- 

 panion is much less than that of the sun— less than a quarter, in 

 fact. This is what we might expect, for Algol and all the 

 variables of its class yet examined give spectra of Group IV., 

 and should therefore represent a less advanced stage of condensa- 

 tion than that seen in our sun. This demonstration of the truth 

 of the satellite theory of variation of the Algol type derives also 

 an especial interest from Prof. Darwin's researches on tidal 

 evolution, for assuming, as we well may, that the cause of 

 variation is the same in all members of the class, we now 

 know of nine stars in which a large companion is revolving 

 round its primary at but a very short distance from it, and in a 

 very short space of time. The companion of U Ophiuchi must, 

 indeed, be almost in contact with its parent star. 



Discovery of a New Comet. — A faint comet was dis- 

 covered by M. Borrelly at j Marseilles, on December 12, at 

 7h. 49-5m. G.M.T. R.A. i8h, 7m.; daily motion in R.A, 

 + im. I2S. N.P.D. 41° 7'; daily motion + 60'. 



GEOGRAPHICAL NOTES. 



We regret to have to record the death of Major Peter Egerton 

 Warburton, whose name will always be intimately associated with 

 the history of exploration in Australia. He died at Beaumont, 

 Adelaide, in his seventy-sixth year. His most famous achieve- 

 ment, undertaken in 1873, was the crossing of the continent from 

 a point on the overland telegraphic line to the De Grey River, 

 in Western Australia. Nothing was heard of him for about 

 twelve months, during which he and his party suffered terrible 

 privations in their march across the desert. After the expedi- 

 tion. Major Warburton visited England, and was awarded a 

 Gold Medal of the Royal Geographical Society for his efforts 

 towards increasing our knowledge of the interior of Australia, 

 He received the Companionship of the Order of St. Michael 

 and St. George in 1875. 



The death is announced of Cardinal G. Massaja in his eighty- 

 first year, at St. Georgio a Cremano, For nearly half a century 

 the name of this distinguished explorer has been intimately asso- 

 ciated with the progress of geographical discoveries in Abys- 

 sinia and the surrounding regions. It was at his suggestion that 

 the Italian Geographical Society organized the Antinori Expedi- 

 tion to Shoa, which has resulted in the occupation of a vast 

 region, and the extension of Italian influence over the whole of 

 Ethiopia. His chief work, " I miei trentacinque Anni nell' 

 alta Etiopia," abounds in valuable geographical, historical, and 

 ethnological information on the East African regions for so 

 many years explored and studied by him. The Cardinal was 

 born at Piova in 1809, and, in 1846, appointed Vicar Apostolic 

 of the Galla nation. 



From the Berlin Correspondent of the Daily News we learn 

 that a full account of the ascent of Kilimanjaro by Dr. Hans 

 Meyer and Prof, Purtscheller has been received at Berlin. It is 

 dated " Marangu Jagga, October 9." The journey from Zanzibar 

 to Uawela took exactly a fortnight. On September 25 the tra- 

 vellers reached Marangu. On October 2 they encamped, with 

 a Pangani negro, on the ridge of the plateau, at a height of 

 14,450 feet. At 2.30 a.m. they started for the lava-ribs sur- 

 rounding the valley of glaciers to the south about 1200 feet 

 above. At 7 o'clock, on the right side of the valley, at an 

 elevation of about 16,500 feet, the first snow was seen under 

 cover of the rocks. The higher they went, the more clefts and 

 fissures the field of ice had. The travellers say :— ' ' After great 

 exertions we reached, at 1.45, the snow-line, and it was seen 

 that the highest peak, which was formed of rocks jutting out of 

 the snow, was about one and a half hour's march to the left. 

 After resting a day and a half we set off, on October 5) ^^o 

 bivouac in the Lava Cave, at a height of about 15,200 feet, 

 and on the next day we repeated the ascent. The peaks were 

 gained without particular difficulty, and on the central and 

 highest one, 19,680 feet above the sea, the German flag was 

 planted." Dr. Meyer proposes to call this peak Kaiser Wilhelm 

 Peak. The view from here on to the Kibbs Crater — which is 

 6600 feet broad and 660 feet high, and the lower half of which 

 is encased in a mighty belt of ice, whilst a volcanic cone of 

 about 500 feet rises in the centre — is magnificent. The beauties 

 of the landscape in the Kilimanjaro region seem to be quite 

 extraordinary. On October 10 the Kimawensi was to be 

 ascended. The two travellers enjoy the best of health. 



The double number of the Bollettino of the Italian Geogra- 

 phical Society for October and November, which appears some 

 weeks behind time, is largely devoted to African subjects, and 

 more particularly to the north-eastern region, which is rapidly 

 becoming an " ItaHan colony," Captain D. Stasio publishes a 

 summary of Don Francesco Alvarez's "Travels in Ethiopia" 

 in the sixteenth century, enriched with valuable notes and addi- 

 tions, Alvarez, a priest attached to an embassy forwarded by 

 Portugal, in 1520, to the Emperor of Abyssinia, shows himself 

 a careful observer of men and things, and his work, which was 

 included in Ramusio's "Navigationi et Viaggi " (Venice, 1588), 

 abounds in details regarding the political, social, and economic 

 relations of that region in the sixteenth century, Giulio D. 

 Cocorda brings to a conclusion his important series of papers 



