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NATURE 



{JiLne 13, 1878 



other planet which the comet can approach with its actual 

 elements is Venus, which, near the ascending node, may 

 be within o'li. 



MiRA Ceti. — According to Schonfeld's calculation the 

 next miiiimnm of this variable will occur on June 23. 

 and the next maximum on October 11. There are com- 

 paratively few observations of the former phase and more 

 attention to it is desirable. At present it is assumed that 

 the perturbations of the maximum deduced from Arge- 

 lander's formula, apply also to the nearest minimum. In 

 this case the sum of the perturbations is +.29"9 days. 



GEOGRAPHICAL NOTES 

 We last week referred to the important work done by 

 Sir Andrew Scott Waugh in connection with the Great 

 Trigonometrical Survey of India, and from the recently 

 issued Report of Colonel Walker, the present Superinten- 

 dent of the Survey, it will be seen that the work is being 

 carried on with unabated energy. The Report refers to 

 1876-77, and tells us that during that year an area of 5,019 

 square miles was covered by principal triangulation; 

 under secondary triangulation 5,400 square miles have been 

 covered with points for the topographical survey, 3,100 

 miles have been operated \vi pari passu with the principal 

 triangulation, and in an area of 23,600 square miles, lying 

 mostly in portions of the Himalayas which are inaccessible 

 to Europeans, a number of points have been fixed which 

 will be valuable for geographical rectifications. The 

 topography of upwards of 5,000 square miles has been 

 completed in scales varying from half an inch to two inches, 

 while several important geodetic operations were accom- 

 plished. In these Reports there is generally some important 

 geographical work to record, accomplished by one of the 

 native officials of the Survey. During the year 1876, the 

 Mullah, one of the purvey explorers, made a survey up 

 the course of the Indus from the point where it enters the 

 plains above Attok, to the point where it is joined by the 

 river of Gilghit. This is the only portion of the Indus 

 which had remained unexplored. Here the river traverses 

 a distance of some 220 miles, descending from a height 

 of about 5,000 feet to that of 1,200 feet above sea-level. 

 Its way winds tortuously through great mountain ranges, 

 whose peaks are rarely less than 15,000 feet in height, and 

 culminate in the Nanga Parbat, the well-known mountain, 

 Avhose height, 26,620 feet, is only exceeded by a very few 

 of the great peaks of the Himalayas. The river in many 

 places is hemmed in so closely by these great ranges that 

 its valley is but a deep-cut, narrow gorge, and, as a rule, 

 there is more of open space and culturable land in the 

 lateral valleys, nestling between the spurs of the sur- 

 rounding ranges, than in the principal valley itself. No 

 European has ever penetrated this region, and the Mullah 

 only managed it by travelling as a privileged trader. 

 Very difficult of access from all quarters, it is inhabited 

 by a number of hill tribes, independent and suspicious of 

 each other, and protected from each other by natural 

 barriers and fastnesses. Each community elects its own 

 rulers, and has little intercourse with its neighbours, and 

 with the outer world only by means of privileged traders. 



The captain of a German steamer, just arrived at Hong- 

 kong, reports a singular condition of things in the island 

 of New Britain, in the South Seas. He found the whole 

 of the north-east coast enveloped in dense smoke, and he 

 experienced great difficulty in proceeding up the channel 

 between it and New Ireland, as fields of pumice-stone, 

 several feet in thickness, covered the surface of the 

 water. On Febniary 9 he reached Makada, Du'^e of 

 York group, and found that three craters had broken 

 out in the New Britain peninsula, at the foot of the so- 

 called Mother and Daughters Mountains, from which 

 dense masses of pumice-stone were continually being 

 thrown up. The passage between Duke of York Island 

 and Blanche Bay had been completely closed by a com- 



pact field of pumice-stone, about five feet in thickness, 

 according to the statement of the captain to a Hongkong 

 paper. A tidal wave swept over Blanche Bay on 

 February 10, and soon afterwards a new island appeared, 

 about three-quarters of a mile in diameter. This island 

 is situated to the south of Natopi, or Henderson Island, 

 and where it now is no bottom was previously obtained 

 at seventeen fathoms. It is probable that other altera- 

 tions have taken place which could not be observed at 

 the time, owing to the masses of floating pumice-stone. 

 The captain of the vessel mentioned further states that 

 the water in Blanche Bay was scalding hot for two days, 

 and that immense quantities of boiled fish and turtle 

 were thrown on shore, and eagerly devoured by the 

 natives, who were starving in consequence of the unusual 

 dryness of the season. 



The party which left England last month for Egypt on 

 their way to reinforce the Church Missionary Society's ex- 

 pedition to the Victoria Nyanza, will proceed by steamer 

 to Suakim, the port of Southern Egypt, accompanied pro- 

 bably by a dragoman engaged by the British Consulate 

 at Cairo. At Suakim it is proposed that they shall engage 

 camels to transport them across the desert to Berber, on 

 the Nile, whence they will travel by steamer to Khartum. 

 From that point they will journey under Col, Gordon's 

 protection, and will, doubtless, have no difficulty in reach- 

 ing Gondokoro. Thence it is arranged that they shall 

 proceed by the Egyptian military outposts to the frontiers 

 of Uganda, in which country Col. Gordon now has an 

 agent, whose presence will no doubt insure safety to 

 Europeans. 



A letter from the French Ogowd Expedition was read 

 at the last meeting of the Geographical Society of Paris. 

 It is quite a year since it was written, and some appre- 

 hensions have been entertained as to the safety of the 

 explorers. M. de Brazza states that the Ogowd is reduced 

 to small proportions and flows from the south, so that it 

 gives the impression of being really an arm detached 

 from the Congo. The expedition was to travel north- 

 wards in order to examine the sources of a powerful 

 affluent. Illness was prevailing amongst the small party, 

 and the hostility of the native tribes was growing 

 stronger. 



The forthcoming congress of the Geographical Society 

 of Paris will not be international, but national, although 

 it will be open to foreigners. The principal aim of the 

 congress will be to organise a federation, between the 

 Paris Society and similar institutions which its influence 

 has started in large provincial cities during the past five 

 years — viz., Lyons, Bordeaux, Marseilles, and Montpelier, 

 where a society for the whole of Languedoc was recently 

 established. 



A Reuter's telegram states that the schooner Eothen 

 will probably sail from New York on Monday next for the 

 Arctic regions to search for relics of the Franklin expedi- 

 tion. No doubt the purpose of this expedition is to obtain 

 the relics reported to be in the possession of some of the 

 mainland Eskimo. 



A meeting of the subscribers to the African Explora- 

 tion Fund of the Royal Geographical Society will be held 

 in the theatre of London University at 3 P.M. on Friday, 

 June 14. Sir Rutherford Alcock, K.C.B., Chairman of 

 the Committee, will preside. 



ON A NEW METHOD FOR DISCO VERING AND 

 MEASURING MOLOTROPY OF ELECTRIC 

 RESISTANCE PRODUCED BY ALOLOTROPIC 

 STRESS IN A SOLID 1 



'T^ORSION of a metal tube within its hmits of elasticity 

 -*■ produces ccolotropic stress, of which the mutually 



perpendicular lines of maximum extension and maximum 



' Abstract of a Paper read by Sir \V. Thomson at the Physical Society, 

 May 25. 



